Superseded - Transportation | Alberta.ca...Superseded Alberta Infrastructure AUGUST 1999 HIGHWAY GEOMETRIC DESIGN GUIDE F-14 ROADSIDE FACILITIES ˛ ˝˚˚ ˜˘˝1’˙ˇ ˚-˙ˇ˝˚

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Alberta InfrastructureHIGHWAY GEOMETRIC DESIGN GUIDE AUGUST 1999

ROADSIDE FACILITIES F-1

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Section SubjectPage

Number Page Date

F.1 VEHICLE INSPECTION STATIONS.................................................................... F-3 April 1995F.1.1 Introduction .................................................................................................... F-3 April 1995F.1.2 Class A VIS...................................................................................................... F-3 April 1995F.1.3 Class B VIS ...................................................................................................... F-4 August 1999F.1.4 Class C Mobile VIS......................................................................................... F-4 August 1999

F.2 HIGHWAY SAFETY REST AREAS ....................................................................... F-13 August 1999F.2.1 Introduction .................................................................................................... F-13 August 1999F.2.2 Class I - Major Rest Areas ............................................................................. F-14 August 1999F.2.3 Class II - Smaller Rest Areas ......................................................................... F-14 August 1999F.2.4 Class III - Rest Areas (Turnouts) .................................................................. F-14 August 1999

F.3 MAJOR DEVELOPMENT ACCESS (HIGHWAY COMMERCIAL) ............... F-16 April 1995

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Alberta InfrastructureAUGUST 1999 HIGHWAY GEOMETRIC DESIGN GUIDE

F-2 ROADSIDE FACILITIES

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Figure DescriptionPage

Number

F-1.2 Class A Vehicle Inspection Station (Standard Layout and Access onDivided Highways)...................................................................................................................................... F-5

F-1.3 Class B Vehicle Inspection Station (Standard Layout and Access onUndivided Highways) ................................................................................................................................. F-7

F-1.4a Class C Mobile Vehicle Inspection Station (Standard Layout and Access onUndivided Highways) ................................................................................................................................. F-9

F-1.4b Class C Mobile Vehicle Inspection Station (Standard Layout and Access on UndividedHighways with AADT Less than 1000.) .................................................................................................. F-11

F-2.2 Class I Major Rest Area (Typical Layout and Access)........................................................................... F-17F-2.3 Class II Rest Areas (Typical Access) ........................................................................................................ F-19F-2.4a Class III Rest Area (Roadside Turnouts) ................................................................................................. F-21F-2.4b Class III Rest Area (Roadside Turnout for High Traffic Volume, AADT >3000, Log Haul

Routes) ......................................................................................................................................................... F-23F-2.4c Class III Rest Area (Roadside Turnouts on Recreational Roads) ......................................................... F-25F-2.4d Typical Class III(b) (Staged) Roadside Turnout on Divided Highways <12,000 AADT .................. F-27F-2.4e Typical Class III(b) (Staged) Roadside Turnout on Divided Highways >12,000 AADT .................. F-29F-2.4f Typical Class III(b) (Staged) Roadside Turnout on Undivided Highways

Future Twinning on Opposite Side.......................................................................................................... F-31F-2.4g Typical Class III(b) (Staged) Roadside Turnout on Undivided Highways

Future Twinning on Same Side ................................................................................................................ F-33F-3 Major Development Access Requirements for Divided Highways..................................................... F-35

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Alberta InfrastructureHIGHWAY GEOMETRIC DESIGN GUIDE APRIL 1995


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Vehicle inspection stations are checkpoints establishedat locations throughout the highway system. Theirprimary purpose is to facilitate enforcement ofregulations governing the trucking industry. Thestations located near provincial boundaries are initialcontact points for incoming vehicles. Those near majorurban centres provide service to the trucking industryby issuing permits, and checking weights prior tovehicle departure from point of origin.

The vehicle inspection station (VIS) standards used inthe province can be divided into three general classes:A, B and C. Standard site layout plans for class A, Band C, including details of access geometrics, areprovided in Figures F-1.2, F-1.3, F-1.4a and F-1.4b.Although these plans show a standard, details of avehicle inspection station, such as scales, buildingsand parking areas, are designed to suit each location.Although the on-site details are customized, theacceleration/deceleration lanes, tapers and turningroadways will have an impact on the level of serviceon the adjacent highway. They should be designedbased on standard highway geometric designconsiderations (functional classification, design speed,divided/undivided, gradient, traffic volume, etc.).Vehicle inspections are also sometimes undertaken attruck turnouts which serve as spot check sites. Theseare described in Section F.2.4.

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Class A is the standard vehicle inspection station fordivided highways. This layout provides a high speedoff-ramp and on-ramp, which ensures minimal impact

on through traffic operations under normalconditions. The standard treatment also includes 600mof acceleration distance, including ramp and parallellane. Depending on the level of service on thehighway and highway grades, the designer mayextend or shorten the parallel lane.

The standard treatment includes a satellite site on theopposite side of the highway, which may allowvehicles travelling in the opposite direction to bechecked also. A median cross-over is generally notprovided, due to the operational problems that canoccur where large vehicles have to cross a busydivided highway.

Generally, if the level of service on the dividedhighway is A, or in the lower half of B (that is, up to21,000 AADT on a typical rural four-lane dividedhighway), the standard acceleration and decelerationlanes are adequate. For higher volumes and/or uphillgradients, longer acceleration lanes may be used. A setof performance curves for the Alberta design truck 180g/w (which is about the 85th percentile mass:powerratio for loaded trucks in the province) is provided. Itenables the designer to gauge the impact of gradientsand estimate the approximate merge speed for heavytrucks. Although 80 km/h is considered a desirablemerge speed, it is frequently not practical to provide asufficiently long acceleration lane to achieve thatspeed, considering that 1200m would be needed on alevel grade. A merge speed of 70 km/h is consideredadequate in general for this type of facility.

Bearing in mind the advantages for truck decelerationand acceleration, it is preferable to locate major VISsnear the top of smooth crest curves, where possible,especially on busy divided highways. The location ofthe access and egress should have good sight distance(decision sight distance is desirable) to facilitate safemerge and diverge manoeuvres.

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Class B is the standard vehicle inspection station forpermanent, manned stations on two-lane undividedhighways. This layout provides for some decelerationand acceleration of vehicles using the station, and italso provides a bypass lane for through traffic. Thelength of the parallel acceleration lane may be varied,depending on the level of service on the highway, anda range of lengths is suggested on the figure. Thetruck performance curves are also included for thedesigner’s use.

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The Class C VIS is the standard layout for portable ormobile vehicle inspection stations. In recent years,some of these sites have been equipped withautomatic weigh scales, which are normallyunmanned and may be used by the public.

The layout includes acceleration, deceleration and bypasslanes, the length of which depend on the traffic volumeon the highway. Notes are included on Figures F-1.4a andF-1.4b as a guideline for provision of auxiliary lanes.

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Highway safety rest areas are considered an integralpart of modern highway systems. They providedrivers with a greater measure of safety, comfort andconvenience. The concept of building acomprehensive network of highway safety rest areasthroughout the primary highway system is expectedto provide benefits to society.

Safety rest areas serve three primary purposes:

• Improve safety by providing places for travellersto rest periodically

• Provide suitable places for emergency stops and

access to toilet facilities, telephones, etc. • Provide tourist and interpretive information for

travellers, create a positive image of the provinceand thus promote tourism.

Although it is difficult to calculate the benefits ofsafety rest areas in economic terms, the U.S.Transportation Research Board has developed apreliminary methodology for calculating the benefits.It is based on the rest area’s role in reducing shoulderstop and fatigue caused collisions. The board has alsosuggested a procedure for estimating the comfort andconvenience value of rest areas. There are otherbenefits such as the beneficial impact on tourism.However, there is not sufficient data available tocalculate these in economic terms.

The safety rest areas currently in use in Alberta can bedivided into four categories:

Class I Major rest areas accommodating cars,recreational vehicles and trucks, andlocated along existing or proposedexpressways and freeways

Class II Smaller rest areas accommodating cars andrecreational vehicles, and usually locatedalong two-lane highways (typical highwaycampground or day-use area)

Class III(a) Basic car, recreational vehicle, and truckturnouts located along all primaryhighways. Class III(a) rest areas are

essentially a shoulder widening withvehicles stopping on the pavementadjacent to the shoulder.

Class III(b) Roadside turnouts for divided highways.This type of turnout is intended toaccommodate all vehicle types and providean offset between the turnouts and thetravel lanes to enhance safety. TheClass III(b) typical design was adopted byAlberta Infrastructure in 1999 for use onthe North-South Trade Corridor and theYellowhead Highway. This type oftreatment is preferred (over the Class III(a)type) for use on all divided highways orhighways that are identified for futuretwinning.

Rest area spacing has been the subject of considerablestudy in the U.S. At present, the average spacing onthe entire U.S. interstate system is approximately 80km. Based on that study and experience in Alberta, ithas been concluded that it is desirable to makeprovision for vehicles to stop on every 90 km length ofhighway. The provision of rest areas on higher volumeroutes, especially divided highways, is most beneficialas this will serve the greatest need.

The optimum spacing for Class III rest areas isaffected by volume and particularly type of traffic.Spacing in this class may vary widely. Turnoutswould normally be quite close together on highlyscenic recreational highways and more widely spacedon low volume non-recreational roads. In general, anaverage spacing of 30 to 40 km throughout thehighway system is considered desirable.

The three classes of rest areas are described in moredetail in the following sections. These descriptions aretypical and actual designs may be different due to siteor traffic demands. It should be noted that only Class Iand III rest areas provide for large truck access andparking. Class II rest areas are generally suitable forpassenger vehicles and recreational vehicles only.When calculating the existing or desired spacingbetween rest areas both Class I and Class III facilitiesshould be considered as they both serve all designvehicles.

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Class I rest areas are recommended only on theexisting and proposed freeway system. Developmentof these rest areas may be staged over a period of timeby developing lower class facilities initially andupgrading to the full Class I standards when trafficwarrants.

Class I rest areas vary in size and services provided,but generally have flush toilets, water and sewersystems, dump stations, picnic areas, wastereceptacles, pet exercise areas, telephone, lighting andlandscaping, and surfaced parking for cars,recreational vehicles and trucks. Travel information isnormally provided. All facilities of the rest area aredesigned to be fully accessible and special designfeatures such as special phones may be provided forthe visually and hearing impaired.

The desirable spacing between Class I rest areas on thedivided highway system is 90 km. For practicalreasons Class III(b) roadside turnouts may be built inlieu of Class I rest areas where there is insufficienttraffic to justify a full Class I facility. The number ofparking spaces is dependent on the anticipateddemand, which is estimated based on traffic volume,traffic composition, functional classification andestimated length of stay. Rest areas should not belocated in or adjacent to urban areas because of thecompetition with commercial facilities and thepotential for increased vandalism.

The typical access/egress to the Class I rest area isshown in Figure F-2.2. Class I rest areas are designedto serve one direction of traffic only, and no mediancrossovers are permitted. The length of decelerationtaper and off-ramp as shown is generally more thanadequate to eliminate interference with the throughtraffic flow on Alberta’s four-lane divided highwaysin a rural setting.

Generally, if the level of service on the dividedhighway is A or in the lower volume half of B, (that is,up to 21,000 AADT on a typical four-lane dividedfacility), the standard acceleration distance as shown isadequate. For higher volumes and/or uphillgradients, longer acceleration lanes may be used. Thegeneral guideline for provision of an additionalacceleration lane for Class A VISs, as outlined inSection F.1.1, may be applied to Class I rest areas also.That guideline is shown on Figure F-1.2.

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Class II rest areas are usually located along two-lanearterial highways and have toilets, picnic facilities,waste receptacles and surfaced or unsurfaced parkingfor cars and recreational vehicles. These areas mayalso include telephone, lighting, well or cistern, andbulletin boards. These rest areas are intended to beday-use only. However, this may be interpreted asallowing overnight stops, especially where campingfacilities are not available within a reasonabledistance.

Class II rest areas are generally accessible only to carsand recreational vehicles. They are usually locatedalong two-lane highways with lower traffic volumes,and should have a 90 km spacing (similar to Class I),dependent on the availability of commercial facilitiesin the area. These rest areas are accessible from bothdirections of travel.

The typical access to a Class II rest area is shown onFigure F-2.3. The typical layout includes a generousprovision for acceleration/deceleration and bypass,which is generally adequate for the volumes that arefound on two-lane undivided highways in Alberta. Incases where the volume on the highway is relativelylow, that is, less than 1800 AADT, a lower standardtreatment may be used. Designers should use theintersection treatment design guidelines as outlined inSection D.6 to design the access to Class II rest areaswhere the highway AADT is less than 1800.

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Class III rest areas, also known as turnouts, arefunctional and desirable elements on heavily travelledroads and on those carrying recreational traffic. Ingeneral, turnouts are paved areas outside the normalcontinuous paved shoulder, where parking space isprovided at a safe distance away from the throughtravel lanes. On undivided highways, turnouts aregenerally adjacent to the shoulder. In 1999 AlbertaInfrastructure adopted a policy of constructingdivided highway roadside turnouts at an offset fromthe highway. The separation is in the range of 50 m.This is intended to enhance safety for road users andprovide a more comfortable facility for weary driversto take a break. This initiative is expected to reducethe prevalence of driver fatigue which can contributeto collisions especially on routes that carrypredominantly long distance traffic.

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Planning studies have been undertaken to identifydesired locations of Class III(b) roadside turnoutsbased on spacing, traffic volumes, proximity to urbancentres etc. Studies have been completed for theNorth-South Trade Corridor and the YellowheadHighway. Studies for other divided highways andfuture divided highway corridors are ongoing.

Construction of the planned facilities will generally beundertaken in conjunction with other major roadworkin the vicinity.

When the location of a highway is in an area ofparticular beauty and where a large percentage of thetraffic volume is recreational, many turnouts may beprovided. Such turnouts provide drivers theopportunity to pull off the through travel lanes, safelystop, and take in the scenery. Litter containers andpossibly washroom and telephone facilities may beincluded in this type of turnout.

Class III rest areas (turnouts) provide the onlyopportunity outside of the Class I rest areas andcommercial sites for large trucks to pull off thehighway.

The maximum desirable spacing for turnouts is 50 to60 km on highways carrying substantial truck traffic.Since turnouts are generally required on both sides ofthe highway, they should be offset by a minimum ofone km. The near side turnout should be located inadvance of the far side turnout. On divided highwaysroadside turnouts are only accessible for one directionof travel and therefore the 50 to 60 km spacing shouldbe used for each direction.

Class III rest areas are required on divided andundivided highways. The typical layouts shown inFigures F-2.4a, b and c are intended for undividedhighways. Figures F-2.4d, e, f and g show typicallayouts for existing or future divided highway routes.The typical turnouts in Figure F-2.4c are intended forrecreational or scenic routes only (generally lowervolume). Figure F-2.4b is used on high volume(AADT>3000) log haul routes, and Figure F-2.4a isused in all other cases.

Figure F-2.4c illustrates two types of roadside turnoutsused on low volume recreational roads. The deep pull-off, usually located at a viewpoint, provides a largepavement area that accommodates angle parking,while the standard pull-off provides a smaller pavedarea for parallel parking.

All of the turnouts (except those on recreationalroutes) include a two metre shoulder adjacent to theparking area. This is provided to facilitate vehicleinspections.

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Generally, it is desirable to provide parallelacceleration and deceleration lanes and tapers withturnouts to ensure safe merging and divergingoperations.

However, because of the high cost of providingadditional lanes and because of the variety of trafficconditions that may exist, a design guideline has beendeveloped to promote greater cost effectiveness. Theguideline is as follows:

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1. If AADT<1000, parallel lanes are not required.

2. If 1000<AADT<3000, standard acceleration anddeceleration lanes as shown on Type A or B ofFigure F-2.4a should be used. The type is chosenbased on highway design designation.

3. If AADT>3000. On log haul routes Figure F-2.4b isused; on all other routes Figure F-2.4a is used. Thedesigner should consider the accelerationcharacteristics of the design truck (180 g/wmass/power ratio) and gradient and provide for asuitable merge speed. The desirable minimummerge speed is 80 km/h; however, 60 km/h isconsidered adequate. The length of parallel laneshould not exceed 600m for practical reasons.

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On rural divided arterial highways, the typical designlayouts shown in Figures F-2.4d and e, may be used.

Ideally, truck turnouts should be located near the topof smooth crest curves, provided that sight distancerestrictions do not occur. This will aid the decelerationand acceleration of trucks using the facility and mayallow the designer to reduce the length of parallellane.

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Figure F-3 illustrates a typical frontage road layout forservice centres along divided highways. For major

commercial developments along undivided highwaysdevelopers should comply with the AccessManagement Guidelines (Chapter I of this document)and the guidelines for design of at-grade intersectionsshown in Chapter D.

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Superseded - Transportation | Alberta.ca...Superseded Alberta Infrastructure AUGUST 1999 HIGHWAY GEOMETRIC DESIGN GUIDE F-14 ROADSIDE FACILITIES ˛ ˝˚˚ ˜˘˝1’˙ˇ ˚-˙ˇ˝˚