Withdrawn - Tii · February 2012 6 Photo 2.7: Off-road cycleway with 1.0m segregation verge (N59 near Clifden, County Galway) Cycle Trail 2.14 The cycle trail is a facility which

Provisions for Cyclists andPedestrians on Type 2 and Type 3single carriageway National Roads

in rural areas

NRA IAN 03/12

February 2012

St. Martin’s House, Waterloo Road, Dublin 4. Tel:+353 1 660 2511 Fax +353 1 668 0009Email : [email protected] Web : www.nra.ie

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mailto:info:@nra.ie

http://www.nra.ie/

Summary:

This Interim Advice Note relates to the provisions for, and design of, cyclist and pedestrian facilitieson Type 2 and Type 3 single carriageway National Roads in rural areas.

NRA DESIGN MANUAL FOR ROADS AND BRIDGES

February 2012 1

NRA IAN 03/12

Provisions for Cyclists andPedestrians on Type 2 and Type 3single carriageway National Roads inrural areas

Contents

Chapter

1. Introduction

2. Overview

3. Planning

4. General Design Principles

5. Cross-sections

6. Geometric Design

7. Junctions and Crossings

8. Construction

9. Drainage

10. Signage and Road Markings

11. References

12. Enquiries

13. Appendices

National Roads AuthorityDesign Manual for Roads and Bridges NRA IAN 03/12

February 2012 2

1. INTRODUCTION

General

1.1 The purpose of this Interim Advice Note isto outline design principles and factors that shouldbe considered by Design Organisations whenproviding cyclist and pedestrian facilities on newType 2 and Type 3 single carriageway NationalRoads in rural areas.

1.2 This Interim Advice Note includes somedesign information for elements of the road cross-section. For more detailed information on roadcross-sections reference should be made to NRAstandard NRA TD 27.

Scope

1.3 This Interim Advice Note gives details onthe road cross-section, geometric design, junctiondesign, construction, drainage and signage androad markings for cyclist and pedestrian facilitieson Type 2 and Type 3 single carriageway projects.

Implementation

1.4 This Interim Advice Note shall be used asdirected by the NRA for the design of new orimproved cyclist and pedestrian facilities on Type2 and Type 3 single carriageway National Roadsin rural areas.

1.5 If this Interim Advice Note is to be used forthe design of local or regional road schemes, theDesign Organisation should agree with therelevant Road Authority the extent to which thedocument is appropriate in any particularsituation.

Definitions

1.6 For definitions of the general road termsused in this Standard such as components of theroad (central reserve, verge, hard shoulder, andhard strip, etc.) see NRA TD 27.

1.7 Particular terms used in this Standard aredefined as follows:

All-purpose road:- A road for the use of allclasses of traffic e.g. not a motorway.

Cross-section:- The road cross-sectionincorporates all elements between the boundariesincluding carriageways, the central reserve,separation zones, hard shoulders, hard strips,verges including any footway, cycle track orbridleway, cutting or embankment slopes, bermsand work space. All dimensions are measuredsquare to the line of the road.

Cycle Lane:- A separate part of the carriagewayfor use by cyclists. The cycle lane forms part ofthe roadway and it is located within thecontiguous road surface. It is not a cycleway andtherefore generally not for the exclusive use ofcyclists. These facilities do not cater forpedestrians.

Cycleway - A facility dedicated for the sole use ofcyclists and, if permitted, pedestrians locatedwithin the road corridor.

Cycle Trail:- A facility dedicated for the sole useof cyclists and, if permitted, pedestrians locatedoutside of the road corridor.

Design Organisation:– The organisationresponsible for undertaking and/or certifying thedesign.

Mainline:- The carriageway carrying the mainflow of traffic (generally traffic passing straightthrough a junction or interchange).

Non-motorised Users (NMUs):- Pedestrians,cyclists and equestrians, including mobilityimpaired users.

Road Authority:- The authority responsible forthe road construction or improvement scheme.

Roads: Urban and Rural:- An Urban Road is aroad which is in a built-up area and has either asingle carriageway with a speed limit of 60km/hor less, or has a dual carriageway (includingmotorways) with a speed limit of 80km/h or less.All other roads are Rural Roads. See also NRATD 9.


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Mandatory Sections

1.8 Sections of this document which form partof the standards the National Roads Authorityexpects in design are highlighted by beingcontained in boxes. These are the sections withwhich the Design Organisation must comply ormust have agreed a suitable Departure fromStandards with the National Roads Authority.The remainder of the document contains adviceand enlargement which is commended to DesignOrganisations for their consideration.

Relaxations within Standard and Departuresfrom Standards

1.9 In difficult circumstances, the DesignOrganisation may relax some elements of thesedesign standards, as specifically provided forwithin this document, and in accordance withNRA TD 9. The Design Organisation shallrecord the fact that a Relaxation has been used inthe design and the corresponding reasons for itsuse. The record shall be endorsed by the DesignOrganisation responsible for the scheme. TheDesign Organisation shall report all Relaxationsincorporated into the design as part of the projectreport at the end of each project managementphase

1.10 In exceptional situations, the NationalRoads Authority may be prepared to agree to aDeparture from Standards where the Standard,including permitted Relaxations, is notrealistically achievable. Design Organisationsfaced by such situations and wishing to considerpursuing this course shall discuss any such optionat an early stage in design with the NationalRoads Authority. Proposals to adopt Departuresfrom Standard must be submitted by the DesignOrganisation to the National Roads Authority andformal approval received before incorporationinto a design layout.

Road Markings

1.11 Please note that all drawings in thisstandard are diagrammatic only. No relianceshould be placed upon them for road markinglayouts for which reference should be made to theTraffic Signs Manual.


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2. OVERVIEW

General

2.1 This interim advice note has beendeveloped to give Design Organisations guidanceon the provision of cycling and pedestrianfacilities, on Type 2 and Type 3 National Roads inrural areas, so as to achieve a consistent quality oflayout and coordinated design appropriate to theanticipated usage and demand in a range ofcircumstances.

2.2 This Interim Advice Note is based oninternational design standards and best practice. Alist of these references is given in Section 11. Theadvice note also incorporates lessons learnt from anumber of trial cycleway projects undertaken inIreland.

2.3 Apart from cycle lanes, all other facilities inthis document are considered to be shared usefacilities for both pedestrians and cyclists, whichis appropriate in the context of a rural setting andexpected low number of users.

2.4 References within this document to cyclingfacilities should be generally taken to include forshared use with pedestrians.

National Cycle Policy

2.5 Current Government policy is set out in theNational Cycle Policy Framework (2008-2020)with the aim to develop “a culture of cycling inIreland to the extent that by 2020, 10% of all tripswill be by bike”. One practical measure to supportthis objective is to provide a National Cycle RouteNetwork which encourages cycling as a transportmode, leisure activity and tourist activity inIreland. The National Roads Authority publishedthe National Cycle Network Scoping Study inAugust 2010, which identified a core network ofhigh-quality routes between the larger towns andcities, and through the regions of greatest interestfor tourist and recreational cycling.

2.6 The National Cycle Network will beapproximately 2000km in length. The networkwill consist of on-road cycleways, off-roadcycleways and cycle trails which make use ofexisting dedicated cycle paths, canal tow paths

and disused railway lines. All of these routes willbe free from motorised traffic.

2.7 Other cycling and pedestrian facilitiesalong new and improved Type 2 and Type 3National Roads will complement the NationalCycle Network by providing additional links toconnect to the adjoining hinterland in each region.

2.8 It is intended that the rural cycle routenetwork will be a safe, attractive, high quality setof facilities catering for all non-motorised users.This will promote cycling and walking to thebenefit of local communities and the generalpublic as a whole.

Facilities for Cyclists and Pedestrians

2.9 For the purposes of this document thefollowing non-statutory definition of cyclist andpedestrian facilities applies:

Cycle Lane

Cycleway

Cycle Trail

2.10 Within the rural environment pedestriansand cyclists have tended to use the same facilities,including footpaths, hard shoulders andcarriageways, with minimal conflict. This ismostly due to the relatively low number ofwalkers in the rural environment. It is recognisedthat any new facilities provided would continue tobe shared and as such the facilities described inthis document will be suitable for the combineduse of both cyclists and pedestrians.

Cycle Lane

The cycle lane forms part of the roadway, it islocated within the contiguous road surface and isdelineated by a single white edge line on the rightas defined in the Traffic Signs Manual and in S.I.No. 181/1997: Road Traffic (SIGNS) Regulations,1997. These facilities do not cater for pedestrians.On all-purpose rural roads without footpaths, theprovision of a cycle lane will give rise todifficulties for pedestrians who would normally


February 2012 5

walk on the road carriageway. If a cycle lane is tobe provided, it should be only in conjunction withan adjoining footpath for pedestrians.

Photo 2.1: Cycle lane in a rural environment(Denmark)

Cycleway

2.11 The cycleway is dedicated for the use ofcyclists and pedestrians and it is an offence formotorised traffic to use it. There are two types ofcycleway:

On-road cycleway

Off-road cycleway

2.12 The on-road cycleway is located within thecontiguous road surface and is separated frommotorised traffic by a segregation strip at least0.5m wide and delineated by road markings. Insome cases other physical markers may be used toclearly define the segregation.

Photo 2.3: On-road cycleway with road makingdelineation

2.13 The off-road cycleway is physicallyseparated from the road carriageway by a verge orsome other form of physical segregation; howeverit remains within the road corridor.

Photo 2.5: Off-road cycleway with 2.0msegregation verge (Denmark)

Photo 2.6: Off-road two-way shared cycleway andfootway (Denmark)


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Photo 2.7: Off-road cycleway with 1.0m segregationverge (N59 near Clifden, County Galway)

Cycle Trail

2.14 The cycle trail is a facility which is distinctfrom the road corridor and comprised of elementssuch as canal tow paths, disused railways andother such paths. The cycle trail is primarily usedfor recreational purposes and may consist of lowerquality construction materials.

Photo 2.8: Cycle trail (Great Western Greenway,Mayo along a former railway line)

Photo 2.9: Cycle trail (New Zealand)


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3. PLANNING

General

3.1 There is a statutory requirement for all-purpose roads to cater for cyclists and pedestriansas well as for motorised vehicles. New roadprojects should therefore include provisions forcyclists and pedestrians. There a number of waysto do this ranging from shared use of thecarriageway to cycle lanes and dedicatedcycleways within the road corridor. In somecircumstances cyclists and pedestrians may bebetter accommodated away from the main trafficroute, such as where an older section of road hasbeen bypassed. In such circumstances cleardirectional signs will be required to ensure thatcyclists and pedestrians are aware of the correctroute to follow.

Photograph No.3.1 – Cycleway along a sectionof old road that has been bypassed

Photograph No.3.2 – Cycleway along animproved section of road, but not paralell

3.2 A successful cycling and walking facility isdependent on the following factors;

Segregation from high-speed motorisedtraffic

route continuity, particularly at roadcrossings;

riding surface comfort, includingmaintenance;

convenience;

route attractiveness

safety

3.3 At the earliest stage of a projectconsideration must be given to the needs andrequirements of cyclists and pedestrians. Thisconsideration should follow a design planningprocess which includes the following stages:

Objectives Definition

Constraints and Opportunities Assessment

Demand Assessment

Cycle and Walking Network Plan

Objectives Definition

3.4 The first stage of planning cycling andwalking facilities for inclusion within a roadproject is to identify the objectives for the facility.

3.5 Planning should commence with a definedset of objectives such as:


February 2012 8

Create a facility that forms part of theNational Cycle Route Network and oflocal recreational walking routes network.

Connect rural settlements which are inclose proximity to each other

Provide a cycle network which passes asclose as possible to centres of population

Provide a cycle and walking route thatconnects to local amenities such as abeach, lake, historic site, woodland,mountains, etc

Opportunities and Constraints

3.6 The next stage before developing the cycleand walking route network plan is to identify anyopportunities and constraints which may have aneffect on the demand for cycling within theproject area.

3.7 Opportunities to increase demand should beidentified and include, but not be limited to, thefollowing:

Existing cycle and pedestrian facilitieswhich could be linked to providecontiguous routes

Tourist destinations within the local areawhich can be readily accessed

Leisure facilities which can be readilyaccessed.

Residential areas which can be serviced

Commercial development areas which canbe serviced

Public transport interchanges to provideaccess to and from the cycle facilities

Areas of natural beauty through which thecycle facility can be routed to enhance theuser experience

Disused railway lines and towpaths whichcan keep costs down and give thecycleway a more natural feel.

Future planning proposals and localdevelopment plans.

3.8 Constraints which may limit demandshould be identified. These include, but are notlimited to, the following:

Steep hills which may cause excessiveexertion should be avoided

Localities within which personal safety,either perceived or real, may be an issueshould be avoided such as places hiddenfrom view or where there is a risk of anti-social activity.

Vehicle entrance crossings

Junction crossings

Demand Assessment

3.9 Demand assessment will determine therequirement for pedestrian and cycling facilitiesfor Type 2 and Type 3 single carriageway roadprojects.

3.10 Determining demand for a cycling andwalking facility within the rural environment canbe challenging. However undertaking a demandassessment will give Design Organisations abetter understanding of the local conditions andenvironment which will enable them to designfacilities that will better satisfy the objectives andultimately encourage new users to take up cyclingand walking.

3.11 Assessing demand for each project mayrequire a mixture of different techniquesincluding:

Estimate use of a facility by comparing itto usage levels of existing facilitieselsewhere with similar surroundingpopulation, land use characteristics etc.

Predict usage on a facility or in an areabased on simple calculations and rules ofthumb about trip lengths, mode shares andother aspects of travel behaviour.

Relate usage in an area to its localpopulation, land use, tourism potentialand other characteristics.


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Predict an individual’s travel decisionsbased on characteristics of the alternativesavailable to them.

3.12 The demand assessment should be used todevelop a map which shows existing and potentialdemand patterns. The mapping should includelocations of trip generators and attractors such asresidential areas, leisure facilities, recreationalareas and tourist spots.

3.13 For more information on modellingtechniques and quantitative methods refer to theNRA Project Appraisal Guidelines.

Route Network Plan

3.14 The cycling and walking route networkplan should be developed from the informationcompiled from the objectives, opportunities andconstraints, and demand assessment exercises.

3.15 The network plan may result in therequirement for facilities which are not adjacent tothe main traffic route and are in fact completelydistinct from the road.

3.16 . To have the most benefit for cyclists andpedestrians, a scheme should seek to complete asection of route in full between significantterminal destinations, which will enableincremental delivery of an overall route networkover time.


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4. GENERAL DESIGN PRINCIPLES

General

4.1 Once the cycling and walking network planhas been developed and a route has beenidentified the appropriate facility must bedetermined.

4.2 When considering the final configuration ofthe cycle facility the Design Organisation shouldalways keep in mind that a successful cyclingfacility must have the following qualities:

route continuity, particularly through roadcrossings

a high quality of ride

convenience

attractiveness

safety

4.3 The cycling and walking network maycomprise of any or all of the following:

on carriageway shared use of roadsincluding the use of hard shoulders

cycle lanes and footpaths

on-road cycleways / footways

off-road cycleways / footways

cycle & walking trails

The mix of facility will be determined byassessing the existing facilities, local road types,traffic flows on the local road network, thenumber of vehicle entrances, the number ofjunctions and other road crossings and comparingthis with the cycle network plan.

Selection of Facility Type

4.4 The appropriate cycling and walkingfacility will primarily be dependent on the speedand volume of motorised vehicles. However itwill also depend on the function of the route forcyclists and walkers and the physical

constraints/opportunities present. Otherconsiderations include the number of HeavyCommercial Vehicles, sight distances, potentialfor parked vehicles, the number and type ofjunctions, property accesses, and other localfactors.

4.5 The suitability of a road to accommodate acycling facility is assessed by quantifying vehiclespeeds and flows, both at peak and off-peak times.Figure 4.1 sets out the motor vehicle speed andflow criteria which are relevant in determining ifthe cycling facility should be a cycle lane or anoff-road or on-road cycleway.

4.6 Figure 4.1 shows that if the 85th percentiletraffic speed is greater than 65 km/h and themainline traffic volumes are over 1000 vehiclesper day then an off-road cycleway or cycle trail isappropriate. Below 65 km/h an on-roadcycleway, cycle lane or shared carriageway can beconsidered relative to the traffic flows and localconditions.

4.7 If, due to a low 85th percentile trafficspeed, an on-road cycleway or cycle lane were tobe considered then the effect of the resultingcarriageway widening on the traffic speed needsto be evaluated. The traffic speed would beexpected to rise due to the reduced traffic calmingeffect of the wider carriageway.

4.8 Off-road cycleways remove cyclists frombusy traffic conditions and provide a higherdegree of comfort when compared to on-roadcycleways. They are particularly appropriate inthe rural environment where there are fewinterruptions due to accesses and junctions.However they require slightly more land and mayrequire additional road sweeping. Howeverprovision of route continuity at side road junctionscan be problematic where turning movements arefairly high.


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Figure 4.1: Selection Chart for Cycleway Type

4.9 On-road cycleways are useful where thephysical road corridor width is restricted, such asbeside water bodies or steep slopes. They canalso be useful in situations where the current roadcross section has a sufficiently wide hard shoulderto accommodate a cycleway and segregationwidth, such as a recently downgraded nationalroad. The disadvantage for on-road cyclewaysinclude the lack security of physical separationfrom motorised traffic for the cyclist, motorisedvehicles could misuse the cycleway, and areduced traffic calming effect due to the apparentwidth of the overall road surface.

4.10 Where possible, off-road cycleways shouldbe provided due to the perceived and real safetybenefits gained by physically separating cyclistsfrom motorised vehicles, so long as junctions are

treated suitably to maintain priority for cyclists asdiscussed later in this report. The use of on-roadcycleways should be limited to especially difficultcircumstances; and in such cases a Departure fromStandards will be required for its use.

One-way Versus Two-way Cycle Facilities

4.11 The one-way cycle facility comprises acycle facility on each side of the road with thedirection of flow matching that of the adjacentcarriageway. Where space permits, this should bethe normal provision as it will meet the naturalexpectations of road users for uni-directionalcycle movements at junctions.

4.12 The two-way option has a cycle facility onone side of the road only with adequate width for


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approaching cyclists to pass each other as well asaccommodating pedestrians.

4.13 The choice of one-way versus two-waycycle facilities must be considered in terms of thelocal context, particularly the number ofjunctions, private entrances, mainline geometry,sightlines (at bends), vehicle turning movements,and track continuity.

4.14 Generally one-way cycle facilities, locatedon each side of the road, minimise the need forcyclists to cross the road. They also create a moreconventional arrangement at junctions than two-way scenarios do. In the one-way situationcyclists will be approaching junctions on the sameside of the road and in the same direction asmotorised vehicles. This places cyclists in the lineof sight of drivers approaching junctions enablingthem to give way where necessary. In certainsituations there may be natural tendency forcontra-flow cycle movements such as where acycle facility provides a convenient route betweendestinations without the need for cyclists to crossthe road. See Section 7 for more details.

4.15 One-way cycle facilities may be preferablewhere steep longitudinal gradients are expected.Cyclists travelling slowly uphill have a tendencyto wobble which increases the overall track widthrequired. Cyclists travelling downhill have anincreased speed and lose some of their ability tomanoeuvre. This combination leads to anincreased risk of conflict between cycliststravelling in opposite directions and is bestavoided by utilising one-way cycle facilities.

4.16 A two-way cycle facility, located on oneside of the road, may minimise the number ofconflicts with vehicle entrances and junctions bylocating the cycle facility on the side of the roadwith the least number of side roads and vehicleentrances. This may be particularly relevant forexample on a coastal route where the cycle trackmay be placed on the seaward side of the road. Italso provides a wider facility which gives a higherdegree of comfort to the cyclist. If widening of anexisting road corridor is required then wideningon one side will reduce the number of propertiesaffected.

4.17 A two-way cycle facility has thedisadvantage that it can increase the need forcyclists to cross the road. It also increases the riskto cyclists at junctions and entrances due to

vehicles not expecting contra-flow cyclistsapproaching from the left, but this concern maydiminish in time as drivers become more used tothe presence of such cycle tracks on the roadnetwork. Suitable signage and visibility will alsoreduce the risk of collision between vehicles andcyclists at such junctions.


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5. CROSS-SECTIONS

General

5.1 The width of each of cycle and walkingfacility elements, including the segregation hardstrip, segregation verge, and outside verge, willdefine its functionality, safety and attractiveness.

5.2 When deciding on cross-section widths fordifferent elements of cycling and walkingfacilities the following points should beconsidered:

the further a facility is from the roadcarriageway the safer the cyclists andwalkers will feel

the wider the facility the higher thecapacity

the more overall width available the moreattractive the facility becomes with thepossibility of landscaping

However these greater widths come at the expenseof land and additional construction costs, andtherefore a balance must be struck.

5.3 The following sections define desirable andabsolute minimum dimensions for the variouselements of a cycle facility under typical usagewithin the rural environment. Where possiblethese should be enlarged, particularly whereincreased usage may be expected such as close todensely populated areas or areas of particularnatural beauty where users may wish to stop toenjoy the view.

5.4 Absolute minimum dimensions should onlybe used in very limited situations such as at pinchpoints or avoiding hazards and shall be treated asa Departure from standard.

5.5 Typical cross-section arrangements areshown on Figures 5.2 through 5.4.

Cycle Facility Width

5.6 Rural cycle facilities are shared usefacilities and as such accommodate both cyclistsand pedestrians at the same time. When defining

the cross-section widths consideration needs to begiven to the likely level of pedestrian and cyclistusage, the anticipated speed of the cyclist giventhe vertical profile, and the space that each userwill occupy when using the facility.

5.7 Experience has shown that pedestrian andcycle flows can be catered for safely on sharedfacilities of restricted width. However this mayinhibit the speed of cyclists and result in somefaster cyclists choosing to remain within the roadcarriageway rather than using the dedicatedfacility. This could undermine the effectivenessof the road improvement scheme for the nonmotorised user. Care is required to ensure that afalse economy does not arise through theprovision of a minimalist facility where a widercycle facility may have succeeded in attractinggreater use.

5.8 The space needed for a cyclist to feel safeand comfortable depends on:

the cyclist’s dynamic envelope; i.e. thespace needed in motion;

the clearance when passing fixed objects;and

the distance from, and speed of othertraffic.

5.9 At low speeds, cyclists are prone to wobbleand deviate from a straight line. For most cyclistsa speed of 11km/h is required to ride comfortablyin a straight line without a conscious effort tomaintain balance. Above this speed the additionalwidth needed when moving is 0.2m. Below thisspeed it is 0.8m.

5.10 The dynamic width of a cyclist, includingdeviation, as 1.0m. The clear space for oneperson walking is 0.6m.

5.11 On two-way cycleways where cyclists needto pass each other 0.5m should ideally be allowedbetween the dynamic envelope of each cyclist.This gives a desirable minimum width of 2.5m fortwo-way cycleways as shown in Figure 5.1.


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Figure 5.1: Width Requirements for Passing Cyclists

5.12 An absolute minimum width for a two-waycycle facility is 1.75m in very limitedcircumstances over short sections. Whenapproaching such a pinch-point cyclists maymoderate their speed to allow passing to takeplace before or after the restricted section, so longas it is short enough.

5.13 The desirable minimum width for a one-way cycle facility is 2.0m. This allows clearspace for a cyclist to pass a pedestrian. It alsoallows cyclists to overtake another cyclist withoutleaving the cycleway. Compacted grass vergesshould be provided alongside the facility to enableevasive action by cyclists or walkers if necessaryduring a passing manoeuvre.

5.14 An absolute minimum of 1.5m may beappropriate for a one-way facility in situations ofvery low pedestrian and cyclist movements. Thisassumes pedestrians walking alone or in singlefile, otherwise two people walking together willblock the route for a cyclist who may beapproaching unseen from behind. Such a narrowfacility is only suitable for use in locations remotefrom housing and attractions where pedestrianswill be rarely encountered.

5.15 If vertical objects such as a wall, a fence ora safety barrier are located immediately adjacentto a cycleway the effective width of the cyclewaywill be reduced. It may therefore be necessary toincrease the overall width, relative to the height ofthe object, to avoid limiting the effective capacityof the cycle facility. Table 5.1 gives guidance onadditional widths required where vertical objectsare located adjacent to the cycle facility.

Type of Edge Constraint AdditionalWidth (m)

Flush or near flush surface Nil

Low up-stand up to 0.15m 0.20

Vertical features from 0.15m to1.2m* 0.25

Vertical feature above 1.2m 0.50* Including bridge parapets etc. over 1.2m for short distances

Table 5.1: Lateral Clearances for Cycleways


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5.16 Where the vertical and horizontalalignments allow for higher cyclist speeds,additional width may be required to give a greaterdegree of separation between the fast movingcyclist, the pedestrian, and the slow movingcyclist travelling in the opposite direction.

5.17 The required cycle facility widths are asfollows:

Facility Type DesirableMinimum (m)

AbsoluteMinimum*

(m)

One-way 2.0 1.5

Two-way 2.5 1.75* Requires Departure from Standards

Table 5.2: Cycle Facility Widths

Segregation Width from Carriageway

5.18 Adequate separation width for cyclists andwalkers from motorised vehicles is essential inproviding a safe and comfortable environment fornon-motorised road users.

5.19 As the speed differential between cyclistsand motor traffic increases, so the greater theseparation required. The separation providesprotection to the cyclist from the vacuum effect ofpassing vehicles, particularly large trucks. It alsoprovides protection from cyclists accidentallyweaving onto the carriageway due to inexperienceor during a passing manoeuvre.

5.20 A cycle lane provides no segregationbetween cyclists and motorised vehicles andshould be used infrequently within the ruralenvironment. A 0.5m wide contra-flow hard stripmust be provided where a two-way cycle lane isrequired.

5.21 Where an on-road cycleway is utilised, thesegregation width is defined by the width of thehard strip. The segregation hard strip has adesirable minimum width of 1.0m; however thiscan be reduced to 0.5m as an absolute minimum.

5.22 The hard strip will be delineated by edgemarkings and enhanced through the use of groupsof yellow hatch markings at intervals as shown onFigure 10.1 in Section10.

5.23 For an off-road cycleway the segregationwidth includes the hard strip along the edge of theroad carriageway and the unpaved verge and ismeasured between the carriageway edge markingand the edge of the cycleway as shown in FigureYY.

5.24 For maintenance purposes the absoluteminimum width of an unpaved verge is 0.5m for atwo-way cycleway, however 0.75m is the absoluteminimum for a one-way off-road due to the lesseroverall width of the one-way facility. Theabsolute minimum passing width between cyclistsand motorised vehicles is 1.25m which provides asafe passing distance.

5.25 At a sufficient width the dividing verge canbe utilised to accommodate roadside features suchas traffic signs and safety barriers (or drainage inlimited circumstances). It can also be landscapedwith suitable plants which may enhance theattractiveness of the cycleway while notcompromising visibility. Maintenance in theverge can be reduced through the use of poor soilswhich inhibit the growth of grasses or planting oflow-growth ground creepers.

5.26 Where it is likely that vehicles may crossthe segregation verge or an absolute minimumverge width is utilised, the inclusion of delineatorposts at 24m centres should be considered.

5.27 The required segregation verge widths areas follows:

Facility TypeDesirableMinimum

(m)

AbsoluteMinimum

*(m)

On-road Cycleway 1.0 0.5

One-way Off-roadCycleway 2.0 1.25

Two-way Off-roadCycleway 2.0 1.0

* Requires Departure from Standards

Table 5.3: Segregation Verge Widths


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Outside Verge Width

5.28 The outside verge width gives separationfrom the adjacent boundary treatment for thecyclist, particularly if the boundary is a highobject such as a fence or a wall. It supports theedge of the pavement and if not provided willrequire an edging kerb instead for this purpose.The outside verge will enhance the overallappearance of the cycling facility through addingto the sense of space along the cycle and walkingroute.

5.29 The required outer verge width is generallya function of the cycleway width and theboundary treatment. Where possible a vergewidth of 1.0m is desirable as it allows for ease ofmaintenance. If a sufficiently wide cycleway hasbeen provided then a verge may not be necessary.

5.30 Where the adjacent cycleway is of limitedwidth the outside verge must consist of compactedsoil with grass over the first 300mm to allowcyclists to take evasive action when passing orovertaking. Where sufficient width has beenprovided in the cycleway and it is not anticipatedthat cyclists will veer out onto the verge then theverge may be surfaced with softer materials. In allcases the verge should have poor soils that willinhibit the growth of grasses and will reduce themaintenance requirement. If a hedge forms theboundary delineation the verge width mustaccommodate expected growth betweenmaintenance periods.

5.31 The outside verge widths are as follows:

DesirableMinimum (m)

AbsoluteMinimum (m)

Outside Verge 2.0 1.5

Table 5.4: Outside Verge Widths

Safety Barriers

5.32 Safety barriers are not required to protectcyclists and pedestrians from motorised traffic onthe adjoining the road. Unless required to protecttraffic from other hazards as defined in NRATD19, safety barriers should not be providedadjacent to a shared cycleway and footway.

5.33 If a safety barrier is necessary, then carefulconsideration must be given to the positioning andconstruction. Cyclists and pedestrians need to beprotected from the hazard posed by safety barrierposts and rails. A safety barrier within asegregation verge can significantly diminish theeffective width of the cycleway if located tooclose to the edge of the facility.

5.34 Where safety barriers are required for roadtraffic they must be located within the segregationverge between the mainline carriageway and thecycleway. If a safety barrier were located on theoutside of the cycleway, the impact zone of anerrant vehicle within the cycleway would beextended from a single point to the full distance itwould take for the vehicle to come to a completestandstill, thereby amplifying the risk of cyclistsand pedestrians of being struck by the errantvehicle.

5.35 The width of the segregation verge, where asafety barrier is to be installed, must include thehard strip or hard shoulder, the set-back, thephysical width of the safety barrier, and another0.5m setback from the rear of the posts to allowfor separation between the barrier and thecycleway.

5.36 Where a cycleway is located behind asafety barrier then a system must be implementedwhich covers safety barrier posts to make themsafe if a cyclist were to fall on one. This may be inthe form of a plastic cap, check rail, or some otherdevice to protect sharp edges.


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Example of safety barrier with check rail across rear ofposts at pinch-point along a two-way cycleway inDenmark.


February 2012 18Figure 5.2: Typical cross-section arrangements


February 2012 19

Figure 5.3: Typical cross-section arrangements


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Figure 5.4: Typical cross-section arrangements


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6. GEOMETRICDESIGN

General

6.1 On-road cycleways and cycle lanes willhave a geometric design contiguous with that ofthe adjacent carriageway and as such thegeometric design criteria of the road carriagewaywill apply.

6.2 Off-road cycleways will generally begoverned by the road geometry, but in someinstances will require to deviate from the roadalignment such as at junctions, steep longitudinalsections, and areas with land constraints.

6.3 Cycle trails will generally follow thenatural features of the surrounding topography orthe alignment of any disused rail line or tow path.However the following design criteria should stillbe used as guidance where possible.

6.4 Cyclists often go out of their way to avoidclimbing a hill, especially where the gradient issteep. They may also try to avoid losing heightonce it has been gained. In some cases it may benecessary to consider an indirect alignment whichavoids steep gradients. If space permits, steepgradients may be mitigated by introducing braided(zig-zag) sections for the uphill sections.However in some situations it may be better tohave a steep route rather than none at all.

6.5 Speed differential between cyclists is likelyto be greater on uphill sections of a hilly routerather than downhill sections and should thereforebe treated in a different way. On the uphillsection cyclists are likely to be travelling slowlyor walking therefore it may be beneficial tosegregate uphill and downhill cyclists.

Design Speed

6.6 Frequent road crossings, tight corner radii,the presence of other users, restricted width andforward visibility all affect the speed with whichcyclists can travel and the effort required.Cyclists tend not to favour cycle routes thatfrequently require them to adjust their speed or tostop.

6.7 Cyclists generally travel at speeds between20km/h and 30km/h on the flat and desire tomaintain speed this speed without losingmomentum due to interruptions such as givingway at junctions. Cycle speeds will vary to agreater degree than motorised traffic according tothe vertical alignment. On steep uphill sectionsspeeds can drop as low as 7km/h, whereas ondownhill sections they can exceed 70km/h. Thesevariations need to be considered carefully duringthe cycle network design as described in Section3.

6.8 A consistent design speed of 30km/h formost off-road cycleways will provide a margin ofsafety for the majority of cyclists. However,where a cyclist would expect to slow down suchas on an approach to a road crossing, the designspeed may be reduced down to 10km/h over shortdistances. In these situations it may be useful toinclude a road marking of ‘SLOW’ if the forwardvisibility is limited.

6.9 The stopping sights distance parameters areas follows:

Design Speed (km/h)

General Provision 30

Acceptable Minimum(over short distances) 10

Table 6.1: Design Speed for Cycleways

Visibility

6.10 The distance over which the cyclist hasvisibility of potential hazards is a critical designfeature.

6.11 When assessing visibility for cyclists twoparameters must be assessed:

Dynamic Sight Distance (DSD)

Stopping Sight Distance (SSD)


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The dynamic sight distance and stopping sightdistance parameters are as follows:

Distance (m)

Minimum DynamicSight Distance (DSD) 65

Minimum StoppingSight Distance (SSD) 35

Table 6.2: Dynamic Sight Distance and StoppingSight Distance

6.12 The DSD is the distance a cyclist requiresto see ahead in order to pass slower cyclists andpedestrians whilst still feeling safe and

comfortable riding. The distance specified inTable 6.2 is the distance covered by a cyclisttravelling at 30km/h in 8 seconds. See Figure 6.1for a diagrammatic representation of DSD.

6.13 The SSD is the distance a cyclist requires toperceive, react and stop safely in adverseconditions. The distance includes a reaction timeof 2 seconds plus the braking distance(deceleration rate of 0.15g).

6.14 The minimum SSD should be increased by50% on loose surface tracks and gradients ofgreater than 5%.

Figure 6.1: Dynamic Sight Distance

Figure 6.2: Stopping Sight Distance


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6.15 Designers should ensure that an object atthe minimum SSD is visible from a range of eyeheights. For cyclists, an eye height range of 1.0mto 2.2m should be used, which accommodates arange of cyclists from children and recumbentusers to adults. The object height should be takenas a range from ground level to 2.2m, as cyclistsneed to be able to observe deformations, holes andobjects which could interfere with safe progress.See Figure 6.2 for a diagrammatic representationof SSD.

6.16 Street furniture, trees and shrubs should belocated outside of the envelope of SSD wherepractical. In particular trees can obscurepedestrians from approaching cyclists. Isolatedobjects with widths of less than 300mm areunlikely to have a significant effect on visibilityand may be ignored if removal is not practicable.For unmovable obstructions wider than 300mm itmay be necessary to provide markings to guidecyclists.

Horizontal Alignment

6.17 To achieve a comfortable ride for cyclists,horizontal radii must allow a cyclist to negotiatethem without a loss of speed.

6.18 The absolute minimum horizontal curvaturefor use on cycleways is as follows:

Design Speed (km/h) AbsoluteMinimum (m)

30 25

10 4

6.19 In situations where the speed of cyclistsneeds to be controlled, alignments with a lowradius can be used as a speed inhibitor. Anabsolute minimum is 4.0m. Any lower and thespeed will drop below 12km/hr which makes itdifficult for cyclists to keep their balance. Suchsituations may include vehicle priority junctionsand areas of anticipated high pedestrian usage. Itis important that cycling speeds do not causeinconvenience or danger to pedestrians.

Vertical Alignment

6.20 Care should be taken in designingcycleways to ensure gradients are kept to aminimum. The type of surface is important onslopes as the ability of tyres to grip the surfacewill depend upon frictional resistance of thesurface coupled with its gradient.

6.21 The speed of travel is another importantfactor to consider, as well as the length ofgradient. Steep gradients can lead to relativelyhigh speeds for descending cyclists or very lowspeeds for climbing cyclists, which cab createhazards for all users of the route. Stoppingdistances also increase significantly on gradientsin excess of 5%. Obstacles and sharp bends at thetop and bottom of steep and/or long gradientsshould be avoided.

6.22 The preferred maximum gradient is 3% forcycleways, but this can rise to 5% over distancesof up to 100m. Where steeper slopes areunavoidable, the limiting gradient is 7% over adistance of up to 30m. Steeper gradients are notrecommended except over short distances. Inmountainous terrain these gradient guidelines maynot be practicably applied and with modernbicycle gearing long steep gradients can bemanaged at low speeds with suitable widthprovision for the wobble factor. On the approachto junctions the gradient would ideally not exceed3%, which is similar to the design rules for roads.Where cyclists have to stop such as at junctions, ashort locally levelled section will be of benefit.

Crossfall and Superelevation

6.23 Crossfalls should range between 1.0% and2.5% to ensure adequate drainage.

6.24 While it is desirable that a cycleway shouldfall from its outer edge to the inside on bends,superelevation is unnecessary because of the waycyclists lean in turns and excessive superelevationshould be avoided due to the potential dangers oficy weather difficulty manoeuvring at slowspeeds.

6.25 These considerations will simplify thecross-section design in terms of level variationacross the overall reservation and associated roadgrading.


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7. JUNCTIONS AND CROSSINGS

General

7.1 A cycle network is only as good as itsweakest feature. Research has shown that aroundthree-quarters of cyclist casualties occur at or nearjunctions (London Research Centre 1994). Anybenefits of providing a cycling facility may benegated if it terminates at or before a junction,without providing safe passage through.

7.2 It is most important that drivers knowwhere to expect cyclists within a junctionarrangement. Layouts that place a cyclist outsidethe driver’s normal field of view are likely to behazardous. Designs that place cyclists in front ofand reasonably close to the driver tend to be safer.Simple layouts are preferred, complex layouts areto be avoided.

7.3 Approaches to crossings should normallybe at right angles to the carriageway. Where cycleroutes are located adjacent to the carriageway andlead to crossing points then ‘jug handle’ layoutsshould be used to place cyclists at right angles tothe traffic flows.

7.4 When designing junctions and crossingsconsideration should be given to the fact thatthese facilities are for use by both pedestrians andcyclists.

Major / Minor Priority Junctions

7.5 The treatment of a major / minor priorityjunction for cyclists is applicable to on-road andoff-road cycleways only. Cyclists on a cycle lanewill be considered as mainline traffic. A cycletrail will cross a minor road using a perpendicularvehicle priority crossing.

7.6 Familiarity to both the driver and cyclistwithin a major / minor priority junction is ofprimary importance, therefore design optionsshould be limited to the following options:

bending in – cycle priority, which shouldbe the norm for one-way cycle routes.

bending out - cycle priority, which suitstwo-way cycle routes (usually with a

raised platform to bring the cycle trackacross the road);

bending out – vehicle priority (to beavoided except where major traffic flowswarrant)

Bending In – Cycle Priority

7.7 The bending in junction treatment for major/ minor priority junctions should only be used forone-way cycle facilities. Vehicles approaching ajunction from the minor road would not beexpecting to give way to cyclists approachingfrom the left. A two-way facility using a bendingin junction treatment would result in cyclistsapproaching minor road from the left and couldlikely put cyclists in an unsafe situation.

7.8 A typical bending in junction treatment fora cycleway will reduce the segregation vergedown to 0.5m at least 30m in advance of thejunction. The cyclist is then given priority throughthe junction with appropriate road markings andtraffic signs. 30m after the junction the standardsegregation verge is restored.

7.9 The bending in junction treatment placesthe cyclist in a highly visibly location relative tothe motorist on the mainline. The left turningmotorist will be in a better position to judge if acyclist will be travelling straight through thejunction, and if so, give them priority.

7.10 Visibility requirements for vehicles atmajor / minor priority junctions shall be inaccordance with NRA TD 41-42. However wherea bending in cycle facility is provided the ‘x’distance must be measured from the outside edgeof the cycle facility.

7.11 The “dwell” area, in accordance with NRATD 41-42, shall be provided immediately adjacentto the carriageway as defined by the nearside edgeof the carriageway. However, where a bending incycle facility is provided, a dwell area behind thestop line must be at least 5m long sufficient tostore one vehicle.


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7.12 The disadvantage of the bending in layoutis that vehicles on the road, proceeding to turnleft, may do so without giving way to cyclists insituations of marginal timing. This is due to theperceived pressures of vehicles following them onthe road behind. However, over the past numberof years, bending in layouts have become morecommon in urban areas and many drivers are nowfamiliar with their operational requirements.Where traffic flows are significant a decelerationlane can be provided to enable a turning vehicle toslow down appropriately.

7.13 The bending in junction treatment is notrecommended at junctions with a large number ofleft turning vehicles from the minor road.

7.14 See drawing JC-01 for a typical example ofa bending in cycle priority junction on a singlecarriageway. The cycle and walking facilityshould be marked across the junction mouth withedge lines and symbols on the carriageway tohighlight the crossing to drivers. (Refer to theexample from Denmark in Photograph No.7.2)

Photograph No.7.1 – Bending-in of Cycleway onapproach to a Junction (Denmark)

Photograph No.7.2 – Cycle Markings at Junction(Denmark)

Bending Out

7.15 The bending out junction treatment formajor / minor priority junctions can be used foreither one-way or two-way cycle facilities.

7.16 The bending out junction treatment isutilised to develop space between the cyclistcrossing the junction and vehicles turning off themainline onto the side road. They take the formof either a cycle priority or vehicle priorityjunction.

7.17 An advantage that the bending out junctiontreatment has over the bending in junctiontreatment is that it gives space for vehicles turningleft off the major road before they encounter thecycle crossing thereby minimising any effect onthe mainline capacity. Also a single vehiclewaiting at the junction can stop closer to thecarriageway thereby reducing the visibilityrequirements.

7.18 Junction priority within a bending outscenario must be assessed in terms of thefollowing criteria:

The general objective to allow cyclists tomaintain speed without being required togive way to turning traffic

Volumes and speed of turning traffic (asdefined in Section 7.20)

Volumes of bicycle traffic

Traffic speed on the main road

any other site specific conditions whichmay affect visibility and safety

7.19 Both forms of priority junction are set backfrom the mainline carriageway allowing cycliststo pass through the junction offset from thejunction interface. It is important for safety thatthe ‘bend out’ is designed so as to provide thecyclist with a straight approach to the crossing. Itmust be introduced such that it does not give acyclist the feeling of a detour and motorists do notget the impression that the cyclist is turning left.


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Bending Out – Cycle Priority

7.20 Generally cycle priority junctions shouldonly be used where the mainline traffic flow isless than 4,000 vehicles per day and the averagevehicle speed is less than 50km/h. Considerationshould also be given to the traffic flows on theside road.

7.21 For a cycle priority junction the bend outshould be introduced gradually to minimise theinconvenience for the cyclist and to allow them tomaintain a reasonable speed through the junction.A minimum radius of 30m should be used.

7.22 Coloured surfacing should be considered toemphasise the existence of the cycle prioritycrossing. The cycle and walking facility should bemarked across the minor road with edge lines onthe carriageway to highlight the crossing todrivers.

Bending Out – Vehicle Priority

7.23 For a vehicle priority junction the bend outshould be introduced a little quicker than the cyclepriority scenario. Using a minimum 10m radius atraffic calming affect can be developed to limitthe cyclist speed approaching the cyclist give wayline.

7.24 See drawing JC-01 for a typical example ofa bending in cycle priority junction on a singlecarriageway. The cycle and walking facilityshould be marked across the minor road with edgelines and symbols on the carriageway to highlightthe crossing to drivers.


February 2012 27

Figure 7.1: Typical junction arrangements


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Grade Separated Junctions

7.25 Grade separated junctions are commonlyfound on highly trafficked all purpose dualcarriageways with traffic speeds in excess of85kph and relatively fast entry and exit speeds onslip ramps. For on-road cyclists conflicts occurover the whole length of merge and diverge areasbetween a relatively slow moving cyclist wishingto continue on the mainline and fast moving entryand exit traffic.

7.26 The Design Organisation should includeoff-road cycle facilities to manage these conflictseffectively. Careful consideration must be givento the design of appropriate crossings including‘jug handle’ crossings on the slip roads as shownin Photograph No.7.3.

Photograph No.7.3 – “Jug-Handle” Crossingfor Cycleway at Grade-Separated Junction

7.27 Consideration should be given to directingcyclists up the diverge slip road, crossing theminor road and rejoining the mainline via themerge slip road. However the vertical gradientswill determine the amount of use by cyclists. If itis likely that cyclists will continue to use themainline then a facility at grade will still bepreferable.

7.28 At major junctions with high flows on theslip ramps in excess of 1,000 vehicles per hour, itwill be preferable to provide grade-separation forcyclists through separate underpasses oroverbridges to suit the overall junction geometry.The minimum width of the cycleway at thesestructures shall be 3m to allow for adequateclearance to parapets or side walls.

Photograph No.7.4 –Bridge Crossing forCycleway at Grade-Separated Junction

Side Roads at Bridges

7.29 For the purpose of maximum permeabilitywithin the overall road network, it is desirable toprovide connections from a cycleway along a dualcarriageway to all local roads that are carried overor under the main road on a bridge.

7.30 Where a connection is provided between acycle facility on the mainline and a minor roadbridge or underpass crossing it should complywith the geometric design requirements asdescribed in Section 6. So as to limit the gradientfor cyclists, a spur link may be required betweensuitable points where both roads are close tonatural ground level. This spur will most likelyrun along the toe of an embankment or the lip of acutting as the case may require.

Roundabouts

7.31 Roundabouts on rural roads will usually bebypassed by a cycleway, with side road crossingsprovided on the arms of the junction asappropriate to provide connections for cyclistsand pedestrians. Such road crossings will typicallybe located 10m to 15m from the edge of thecirculatory carriageway so as to enable exitingtraffic to appreciate the presence of a cyclist orpedestrian crossing the road.


February 2012 31

7.32 Approaches to crossing points should belaid out to suit smooth cycling with splayedcorners and minimum 4m radius curves.

7.33 Refuge islands at roundabout crossingsshould be at least 3m wide to enable cyclists andpedestrians to make a staged crossing if necessaryand to await a gap in traffic.

7.34 Controlled crossings at roundabouts forpedestrians and cyclists, such as a zebra crossing,will rarely be appropriate in a rural area with lowfrequency usage. However, a controlled crossingmay be worth considering at locations where largenumbers of users may be expected such as at abusy amenity site.

Road Crossings for Cyclists and Pedestrians

7.35 When a cycle facility crosses a road,selection of the most appropriate location andform of crossing requires careful assessment. Theselection process depends on the interaction andresolution of site-specific factors, (such asproximity to a school), with the safety of thevulnerable road user being of paramountimportance. Depending on the relative volumes oftraffic, a crossing may be either at grade orthrough an underpass or bridge.

7.36 Approaches to at-grade road crossingsshould normally be at right angles to thecarriageway. Where cycle routes are locatedadjacent to the carriageway and lead to crossingpoints then ‘jug handle’ layouts should be used toplace cyclists at right angles to the traffic flows.

Photograph No.7.5 –At-grade Road Crossingwith Bending for Cycleway (N59 at Newport,

Co. Mayo)

Photograph No.7.6 –At-grade Road Crossingwithout Bending for Cycleway (N59 at

Derrylea, Co. Galway)

Photograph No.7.7 –Underpass Crossing forCycleway at Main Road (Denmark)

At-grade Road Crossings – All Purpose DualCarriageways

7.37 The crossing of an all purpose dualcarriageway may be used to connect two cyclefacilities on opposite sides of the road or toprovide access to an area of interest.

7.38 The crossing requires a minimum medianwidth of 5.0m for staging.

7.39 A left-right stagger within the medianshould be provided with a minimum length of10m. The left stagger ensures that users turn leftto face oncoming traffic.


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7.40 The cycleway width within the medianshould be maximised for comfort of slow-speedcycling and storage. A desirable minimum widthof 3.0m is required with additional clearances tofixed objects as necessary.

7.41 Cyclists approaching the crossing need notbe forced to dismount however they should beslowed on the approach in preparation of givingway at the crossing point.

Crossings at Direct Accesses

7.42 Cyclists should be afforded priority at allfootpath crossings and vehicle entrances so as tomaintain momentum and to respect the naturalexpectation of priority for the through movement.

7.43 Visibility requirements for vehicles atdirect accesses shall be in accordance with NRATD 41-42. The ‘x’ distance shall be measuredfrom the nearside edge of the carriageway withoutthe need to accommodate the cycle facility.

7.44 Additionally a direct access crossing acycleway will require a visibility splay setback2.0m (‘x’ distance) from the cycleway with astopping sight distance of 35.0m (‘y’ distance).

7.45 The “dwell” area, in accordance with NRATD 41-42, shall be provided immediately adjacentto the carriageway as defined by the nearside edgeof the carriageway. However, a dwell area isbetter provided behind the cycleway withsufficient space to store one vehicle.

7.46 The cycleway pavement construction mustbe carried across an access to a property so as toclearly indicate the priority for the through cycletraffic. Cycle symbol road markings should beprovided at the crossing to reinforce thearrangement.

7.47 The vertical alignment of the cyclewaymust carry across an entrance without interruptionor dishing.


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8. CONSTRUCTION DETAILS

General

8.1 The type and quality of the cyclewaysurface and construction affects the comfort andattractiveness of a route and the whole-life costsof the project. A good quality specification willminimise maintenance and repair costs over thelong term.

8.2 Cycle lanes will generally have the samepavement construction as the mainlinecarriageway.

8.3 Cycleways do not suffer from the samedegree of wear as motor vehicle routes and maybe of much lighter construction than a roadpavement. These light pavements are notspecifically covered in the general guidance forroad pavements elsewhere in the NRA DMRB.However, the materials specifications andconstruction techniques used will be consistentwith the relevant requirements of the NRADMRB and the Manual of Contract Documentsfor Road Works (NRA MCD).

8.4 This advice note provides guidance on bestpractice pavement construction for cyclewaysbased on trials in a pilot scheme. Typicalconstruction details are included in Figures 8.1and 8.2.

Pavement Construction to Formation Level

8.5 Cycleway pavements will generally beconstructed of bituminous macadam. Howeverthere may be some instances where thebituminous surface is not suitable or desirable.Some cycle trails have been constructed with anunbound grit surface, which has merit in terms oflow-energy construction and aesthetic quality in arural environment. Such grit surfaces may not suitall cyclists, especially for bicycles with narrowwheels and high pressure tyres that would bemore vulnerable to puncture on an unbound

surface. The selected pavement constructionmaterial will depend on the purpose and expectedlevel of use of the cycleway, the constructionmethods available, stability of the sub-grade,drainage, frost susceptibility, aesthetics, anddesign life required. Typical pavement options areincluded in Table 8.1.

8.6 Bicycles are more sensitive to ride qualitythan motor vehicles due to their lack ofsuspension and narrow wheels. Some oldercycleways are poor in terms of ride quality andsurface level tolerance, which is probably due tothe lack of appropriate construction details andspecified level tolerances. It is desirable toprovide a finished surface quality for a cyclewaythat meets the minimum requirements of Series700 of the Specification for Roadworks.

8.7 In the absence of specific constructiondetails for cycleways, the footway detail as shownon NRA RCD/1100/4 of the NRA MCD RoadConstruction Details has been used in the past.This form of construction is not suited to achievetolerances specified in Series 700 of theSpecification for Roadworks. The thin footwaypavement design is vulnerable to ridging of thesub-base due to the use of vibrating rollers forcompaction. The sudden transition from sub-baselevel tolerances to surface tolerances through asingle 50mm thick layer of bituminous macadamis not sufficient to compensate for ridging in thesub-base which is then reflected in the surfacelayer.

8.8 The recommended pavement constructiondetail that will limit problems of ride quality forcycleways is as follows:

20mm thin surface course macadam;

40mm to 55mm base or binder course;

150mm 804 sub-base (machine laid).


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Typical Cycleway Surfacing OptionsSurface Comment

Asphalt orBituminous

Preferred surface, suitable for high flow routesLower long term maintenance costs.

Surface dressedbase course

More suitable in rural environments.Preferred to unbound surfacing.Allows for colour variation through choice of chippings. Fibre-reinforced surfaces add strength

Unbound Not generally recommended except on very quiet routes or in mountainareas where most bikes are of a suitable type. Can be dusty when dryand can result in unpleasant spray when wet. Prone to erosion by poordrainage. Can have higher long term maintenance costs, and is proneto damage by horses and farm vehicles.

Table 8.1: Typical Cycleway Surfacing Options

Photograph No.8.1 – Cycleway with Grit Surface(Great Western Greenway, Co.Mayo)


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Construction - General

8.9 Most damage to a cycleway pavement islikely to occur during the construction process dueto the use of heavy weight machinery. It isessential that suitable lightweight equipment isused to avoid deformation of the pavement andfoundation. Such equipment is readily availableand should be specified in the ConstructionContract using current guidance from the NRA.

8.10 Direct delivery of materials, such as stoneand macadam using normal trucks travelling onthe cycleway should be avoided. It will probablybe necessary to deliver such materials from theside if adjacent to the road, or by transfer withsmaller equipment.

Photograph No.8.2 – Lightweight ConstructionEquipment on a Cycleway Scheme (Note therubber tracks to prevent damage to pavement)

Foundations for Cycleway Pavements

8.11 Many cycleways will be constructed onpoor ground. For reasons of economy it isdesirable to avoid the need to excavate softground beneath a lightweight cycleway, whichwill not give rise to significant settlement inoperation. The critical design factor will thereforebe the weight of construction plant duringconstruction, which should be as light as possible.

8.12 Trials have shown that it is possible toconstruct a floating cycleway to a high qualitystandard across very soft ground using a suitablefoundation layer with geotextile and stone fillsandwich construction as shown in PhotographsNo.8.3 to 8.6.

Photograph No.8.3 – Geotextile base forFloating Lightweight Construction

Photograph No.8.4 – Detail of TypicalGeotextile Base Layer

Photograph No.8.5 – Lightweight RollerCompacting Foundation for Cycleway


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Photograph No.8.6 – Completed FloatingLightweight Construction for Cycleway

8.13 The cycleway pavement foundation shouldbe designed to the road design standards inVolume 4 of the NRA DMRB.

8.14 Where necessary due to soft groundconditions, capping should be placed inaccordance with Series 600 of the Specificationfor Roadworks. Typically a minimum of 350mmof capping material will be required, possibly witha geotextile membrane at sub-formation.

8.15 The Designer may choose to strip thetopsoil, in which case the top of the capping layeris likely to correspond to original ground level,and the finished cycleway surface will be aboveground level to suit over-the-edge drainage.

8.16 It may be preferable not to strip the topsoillayer so as to avail of the natural load-spreadingcapacity of the “scraw” (vegetation and root layer)on soft soils such as peat. Overall settlement ofthe cycleway under its own self-weight is of littleconcern for the final vertical alignment of theroute, and therefore it would be acceptable toleave the original ground undisturbed in theconstruction.

Sub-Base Construction

8.17 A minimum of 150mm of sub-base must belaid in accordance with Series 800 of theSpecification for Roadworks.

8.18 So as to achieve the desired level toleranceand associated ride quality, trials have shown thatthe sub-base should be laid with a paver as shown

in Photograph No.8.6. Mini-pavers are availablethat can lay to the narrow widths required for acycleway.

Photograph No.8.7 – Paving machine layingsub-base for a Cycleway

Bound Pavement and Surfacing

8.19 The bituminous pavement must be laid andcompacted with suitable lightweight machinery asshown in Photograph No.8.7.

Photograph No.8.8 – Lightweight rollercompacting Cycleway pavement

8.20 The recommended thickness of thebituminous pavement is 60mm to 75mm in twolayers with a fine-aggregate surface course 20mmthick. However, trials have shown that withsuitable quality control during construction toachieve the required level tolerances and ridequality, the surface course layer may be omittedand that a single 55mm thick layer of bindercourse should suffice.


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Pavement Edge Detail

8.21 A stepped edge detail, as per NRA RCD700/1, shall be formed on the low edge ofcycleway pavement to suit over-the-edge drainageand to prevent surface water runoff from blockingback onto the paved surface due to accumulationof grass and soil in the verge.

Verge Detail

8.22 It is desirable to inhibit grass growth on thesegregation verge between the road and thecycleway so as to minimise or eliminate the needfor maintenance. Initial trials have used a thin andstony soil in the verge to restrain the rate of grassgrowth, as shown in Photograph No.8.9.

Photograph No.8.9 – Stony Soil in SegregationVerge to inhibit grass growth

8.23 Ideally the verges should be left to self-seedwith local plant types from the surroundingterrain, in line with best practice for sustainability.Some cycleways will traverse through SpecialAreas of Conservation and Natural HeritageAreas, in which case it is especially important notto introduce native grass species in the grassverges.

8.24 Trials are ongoing on a pilot scheme on theN59 at Derrylea near Clifden, Co.Galway, wherethe initial growth of grass in the verge appears tobe appropriately slow as shown in PhotographNo.8.10 taken about 5 months after construction.This trial will be monitored to confirm the successor otherwise of the verge construction details. Ifnecessary, the construction detail will be adaptedfurther on other planned cycleway schemes in

Donegal, Mayo and Kerry from which additionallessons may be learnt

Photograph No.8.10 – Pilot scheme with TrialGrass Verge Detail (N59 at Derrylea)


February 2012 39Figure 8.1: Typical cycleway construction detail (Part 1)


February 2012 40Figure 8.2: Typical cycleway construction detail (Part 2)


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9. DRAINAGE

Surface Crossfall

9.1 Cycle facility surfaces need to beadequately drained to avoid the difficulties thatstanding water and ice can create for cyclists. Acycle facility should be constructed with acrossfall generally between 1.0% and 3.0%, witha maximum of 5.0% over short sections.

9.2 Where a cycle facility forms part of thecontiguous road surface then the road crossfallshould be continued across its extent. Howeverwithin superelevated curves the crossfall can bereduced across the width of the cycle facility so asnot to exceed 5%.

Surface Water Collection

9.3 Surface water runoff from rural all purposeroads is preferably collected from over-the-edgeby drainage ditches or by direct runoff intocombined surface water and ground water filterdrains. In some limited areas runoff may becollected by a kerb and gully system, but thisshould be avoided if possible as it is not reallysuitable in a rural area.

9.4 Where a cycle lane or on-road cycleway isproposed, as either a new construction or animprovement to an existing road, a surface watercollection system should be provided inaccordance with Standard HD 33 of the NRADMRB.

9.5 Where an off-road cycleway is proposedrunning parallel to the mainline, surface waterrunoff can be collected either within thesegregation verge or may be allowed to flowacross the cycleway and over-the-edge into adrainage ditch.

9.6 Cycle trails should, where possible, usenatural drainage or small drainage ditchesconnected into existing watercourses as shown inPhotograph No.9.1.

Over-the-edge Drainage

9.7 Section 3.18 of NRA DMRB Standard HD33 states that over the edge drainage is

‘inappropriate for usage in locations wherefootways or segregated cycleways abutcarriageways’. However a recent trial projectwhich has utilised over-the-edge drainage across acycleway, in both cutting and fill situations, hasproved successful, which indicates that HD33should be revised to remove the above limitationon the drainage system. On all but very widemulti-lane roads, the transverse surface water flowon the pavement will be very shallow in normalrainfall events when cyclists and pedestriansmight be present on the route. Such water on thecycleway surface will not be of concern in termsof safety or comfort. In addition, with asegregation grass verge there should be a degreeof infiltration of surface water to diminish theresidual surface flow that could cross onto thecycleway.

Photograph No.9.1 – Small Drainage Ditch fora Cycle Trail

9.8 Over-the-edge drainage is the preferredarrangement for a rural road with a cyclewayadjoining, as this will greatly simplify theconstruction detailing and scheme cost as well asadding to the overall sustainability andenvironmental fit of the new or improved road.

9.9 Where over-the-edge drainage is used it isimportant to ensure that the surface water runoff


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flows off the cycleway towards the drainage ditchand does not pond. Suitable crossfall of minimum1% and maximum 3% should be provided on thecycleway pavement.

9.10 The separator verge must be constructedwith a crossfall of no more than 10% so as not todestabilise an errant cyclist. No minimumcrossfall is specified for the verge as waterinfiltration is desirable to limit and attenuate theoverall runoff to the receiving watercourse.

9.11 The outside pavement edge detail(RCD/700/1) of both the carriageway andcycleway should be higher than the proposedground level by the depth of the pavementwearing course to stop back flow of the surfacewater runoff from a flat verge.

9.12 The typical construction details shown inFigures 8.1 and 8.2 assume a road formationprofiled with a 2.5% camber which provides adrainage path to the road edge underneath theverge and cycleway through extension of thecapping layer or sub-base laterally. This alsoprovides a drainage path for any surface waterthat permeates through the separator verge intothe sub-base.

9.13 The separator verge should constructedfrom suitable fill material with a 50mm thickstony topsoil layer at the surface.

Open Drainage Systems

9.14 Drainage ditches, grassed surface waterchannels and swales have an advantage over afilter drain in that they better satisfy sustainabledrainage principles including flood attenuationand pollution control by slowing water flow andallowing settlement of suspended solids andabsorption of pollutants by vegetation. Opendrainage systems are therefore preferable to pipedsystems on both an environmental and a costbasis.

Drainage Ditch

9.15 The details for a suitable drainage ditch areshown in Figures 8.1 and 8.2. It has 45 degreeside-slopes and a 300mm base width. The depthwill be determined by the road sub-formationlevel, but will typically be 0.6m so as to reach a

depth of 100mm below the capping layer ifpresent. On this basis the typical width of theditch will be 1.5m at the ground surface.

9.16 A drainage ditch should be located outsideof the outer verge along the cycleway so as toprotect an errant cyclist from toppling into theditch.

Photo 9.3: Off-road cycleway with over-the-edgedrainage and ditch

9.17 Normally the longitudinal profile of adrainage ditch will generally follow the roadvertical alignment, which will limit the gradientand lower risk of erosion due to fast water flow.This is desirable to slow the water runoff speedfor attenuation reasons and to allow for settlementof any water borne pollutants from the road. Trialshave indicated that ditches do not normallyrequire to be lined with topsoil. The subsoil (andpossibly rock) in the excavation will usuallybecome vegetated in a short time with suitablelocal plant varieties as shown in Photograph 9.4.

9.18 Where there is a risk of high velocity flowin a ditch that would lead to erosion, such as onthe final link to an outlet, it may be necessary toplace small rocks in the ditch to absorb the flowenergy and reduce the risk of erosion of clay.

9.19 Where a drainage ditch is less than 1.2mdeep and has no more than 600mm of standingwater, in accordance with NRA Standard TD19 itis not considered a hazard for traffic that mightstray off the road. Therefore a safety barrier willnot be necessary due to the inclusion of a drainageditch within the clear zone from the road edge.

9.20 See NRA TD 19 and Section 5 for all othersafety barrier requirements.


February 2012 43

Photograph No.9.4 – Natural vegetation in adrainage ditch: self-seeded

Grassed Surface Water Channel

9.21 Within the segregation verge a grassedsurface water channel can be used to collectsurface water runoff from both the carriagewayand the cycleway when located within a cutting orat grade. See Figure 8.2 for details.

9.22 This channel would be located within asuitably wide segregation verge. The channelshould be a rounded dished shape that isapproximately ¾ of the segregation verge widthand has a depth of approximately ¼ of the widthof the dish.

9.23 The channel should be constructed fromsuitable fill material which will allow for somegrowth of local vegetation but be robust enough toresist being eroded prior to growth taking hold.

9.24 The grassed channel surface water flow canbe collected within catch-pits that sit in concretesurrounds. These in turn can either connect intoexisting road drainage or discharge into existingwatercourses.

9.25 Where a shallow grassed surface waterchannel is used due to limitations of space it canbe complemented by a fin drain for sub-surfacedrainage as necessary.

Photo 9.5: Off-road cycleway with grassed drainagechannel in segregation verge

Swales

9.26 A Swale is similar in function to a grassedsurface water channel but has very shallow sideslopes of about 1 vertical to 3 or 4 horizontal. Thewide shallow shape provides greater delay tosurface water flow and increases the degree ofboth attenuation and pollution control. It shouldbe used in preference where there is sufficientspace available. However, the acquisition ofadditional land would not usually be justified toaccommodate swales in all locations as theadditional benefits are only marginal compared toother open drainage systems.

9.27 A typical example of a swale is shown inPhotograph No.9.6 at the construction stage andbefore vegetation has grown.

Photograph No.9.6 – Swale before grassgrowth


February 2012 44

9.28 The same swale is shown in PhotographNo.9.7 about a year later when it is fullyvegetated.

Photograph No.9.7 – Swale after grass growth

Filter Drains

9.29 Filter drains involve the use of costlyartificial materials such as pipes, graded stonetrench fill, geotextiles and Blockwork catchpits.Open drainage systems are much cheaper bycomparison.

9.30 Filter drains are also poorly suited tosustainable design principles for a scheme in anatural environment. They should be avoided asmuch as possible, with the preference for opendrainage ditches.

9.31 Where space is tight, filter drains may beused on off-road cycleways can be used to collectsurface water runoff within the segregation vergebefore it crosses onto the cycleway surface.

9.32 When using filter drains considerationneeds to be given to stone scatter and the locationof safety barriers.


February 2012 45

10. SIGNAGE AND ROAD MARKINGS

General

10.1 All signage and road marking used on apublic road must comply with the current TrafficSigns Manual. Where a cycle trail is providedoutside of a road corridor it may contain othertypes of signs and markings that are not includedin the Traffic Signs Manual.

Signage

10.2 The basic shared facility traffic sign (RUS058), as shown in Photograph No.10.2, should beused at all intersection points where cyclists orpedestrians may gain access to the cycleway. Thissign will give legal definition to the facility as forthe exclusive use of cyclists and pedestrians.Other variant signs may be used where there issegregation between the cycle lane and footpath.

10.3 A coherent route direction signage strategymust be developed which gives users cleardirection when using the facility. For a cyclingfacility to be successful, users should be madeaware of the facility so that they can avail of it.The signage strategy is not limited to the routeitself but must also advise potential users withinthe wider area of the presence of the route.

Photo 10.1: Sign indicating the presence of agreenway

Photo 10.2: Direction Signs at a junction ofgreenways

10.4 Signs should not be too intrusive in therural environment. Rather they should be inkeeping with the surroundings as much aspossible by for instance using natural materialssuch as timber rather than steel posts as shown inthe example in Photograph No.10.3.

Photo 10.3: Cycleway sign using a wooden post


February 2012 46

Cycleway Road Markings

10.5 Minimal road markings are required for acycleway. The upright sign will normally sufficeto define the starts and ends of sections betweenaccess points. Shared surfaces need no delineationas both pedestrians and cyclists naturally avoideach other within a shared facility.

10.6 Off-road cycleways may be identified bypainting a combined cycle and pedestrian symbolon the surface at the beginning and end as well asmajor road crossings.

10.7 Cycle symbols (M116 TSM) and Pedestriansymbols (M111 TSM) may be used intermittentlyto identify the cycleway as shown in PhotographNo. 10.4. These symbols are most useful at accesspoints and junctions as highlighted in Section 7and as shown in Photograph No.10.5

Photograph No.10.4 – Intermittent Roadmarkings on a Greenway

Photograph No.10.5 – Cycleway Roadmarkings at a Junction

Cycle Lane Road Marking

10.8 Road markings are essential to delineatecycle lanes that are on the road. These markingsdefine the cycle lane in both legal and physicalterms.

10.9 In accordance with the relevant Regulationsand Chapter 7 of the Traffic Signs Manual theedge of the cycle lane on the side nearest roadtraffic should be indicated by a continuous100mm or 150mm white line. A broken 150mmwhite line should be used where general trafficmay cross the boundary of the cycle lane forexample at a junction. Access to a property ispermitted across a continuous cycle lane edge lineand so breaks in the line are not necessary atentrances.

10.10 Where a contra-flow cycle lane is providedadditional hatched separation is required.

10.11 The nearside edge of the cycle lane shouldbe indicated by a broken 150mm yellow line.

10.12 Cycle symbols (M116 TSM) should beused intermittently at typically 100m intervals toidentify the cycle lane.

On-road Cycleway

10.13 A typical one-way on-road cyclewayshould be delineated as shown in Figure RM-01.

10.14 The nearside edge of the carriagewayshould be indicated by a broken 150mm yellowline as normal for any all-purpose road. The edgeof the cycle lane nearest the road should beindicated by a continuous 150mm white line.

10.15 The separation strip should be identified bydiagonal yellow hatching. This hatching shouldconsist of a group of 4 hatch markings at 45degrees repeated at least every 96m down to every24 metres as necessary.

10.16 Each hatch line may include a raised profilerib in running longitudinally along each hatch to aheight of 8mm above the hatch paint. Thisprovides a tactile feedback to motorised vehiclesthat may cross into the hatched area.Alternatively the hatch painting may be laid to athickness of 11mm.


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Photo 10.3:

Cycle Trail Signs and Markings

10.17 Cycle trails require no road markings andshould be identified solely by signs.

Delineator Posts in Segregation Verges

10.18 Delineator posts may be provided at 24mcentres to discourage vehicles crossing thesegregation grass verge and to highlight theseparation between the road and the cyclewaywhere they are closely aligned.

Photo 10.3: Delineator Posts in Verge

Bollards

10.19 Bollards may be useful to restrict access toa cycleway by motorised vehicles. Such bollardscan also support suitable signs.

Photograph No.10.6 – Bollard at Access Pointto Greenway


February 2012 48Figure 10.1: On-road cycleway road marking

National Roads Authority NRA 03/12Design Manual for Roads and Bridges

February 2012 49

11. REFERENCES

Design manual for Roads and Bridges (DMRB)

11.1 NRA TD 19 (NRA DMRB 2.2.8A) –Safety Barriers.

11.2 HD 33 (NRA DMRB 4.2.3) – Surface andSub-surface Drainage Systems for Highways.

11.3 NRA TD 9 (NRA DMRB 6.1.1) – RoadLink Design.

11.4 NRA TD 10 (NRA DMRB 6.1.1B) – RoadLink Design for Type 2 and Type 3 DualCarriageways.

11.5 NRA TD 27 (NRA DMRB 6.1.2) – CrossSections and Headroom.

11.6 TD 22 (DMRB 6.2.1) – Layout of GradeSeparated Junctions.

11.7 TD 16 (DMRB 6.2.3) – Geometric Designof Roundabouts.

11.8 TD 40 (DMRB 6.2.5) – Layout of CompactGrade Separated Junctions.

11.9 NRA TD 41-42 (DMRB 6.2.6) – GeometricDesign of Major/Minor Priority Junctions andVehicle Access to National Roads.

11.10 TA 90 (DMRB 6.3.5) – The GeometricDesign of Pedestrian, Cycle and EquestrianRoutes.

Other References

11.11 Classification and Grading for RecreationalTrails (ISC, Dublin, 2008).

11.12 Connect2 and Greenway Design Guide(SUSTRANS, Bristol, 2009).

11.13 Cycle by Design 2010 (TS, Scotland,2010).

11.14 Cycle Infrastructure Design – LocalTransport Note 2/08 (TSO, Norwich, 2008).

11.15 Cycle-friendly Infrastructure – Guidelinesfor Planning and Design (CTC, Godalming,1996).

11.16 Design Manual for Bicycle Traffic(CROW, Netherlands, 2006).

11.17 Ireland’s First National Cycle PolicyFramework (DTTAS, Dublin, 2009).

11.18 Making Way for the Bicycle (SUSTRANS,Bristol, 1994).

11.19 Provision of Cycling Facilities – NationalManual for Urban Areas (DoELG, Dublin, 2006).

11.20 The National Cycle Network – Guidelinesand Practical Details (SUSTRANS, Bristol,1997).

11.21 Traffic Signs Manual (DTTAS, Dublin,2010)

11.22 National Cycle Manual (NTA June 2011)

National Roads Authority Volume 6 Section 3Design Manual for Roads and Bridges Part 3 NRA TD 69/10

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12. ENQUIRIES

12.1 All technical enquiries or comments on these guidelines should be sent in writing to:

Head of EngineeringNational Roads AuthoritySt Martin’s HouseWaterloo RoadDublin 4

……………………………………………………...Tim AhernHead of Engineering