Chap 4 Cross Section Elements (pp.4-1 – 4-66 )

Chap 4 Cross Section Chap 4 Cross Section ElementsElements(pp.4-1 – 4-66 )(pp.4-1 – 4-66 )

The following topics (pages) are The following topics (pages) are covered in this lecture:covered in this lecture:

Pavement (p.4-1 – 4-7)Pavement (p.4-1 – 4-7) Lane width (p.4-7 – 4-8)Lane width (p.4-7 – 4-8) Shoulders (p.4-8 – 4-14)Shoulders (p.4-8 – 4-14) Drainage Channels (p.4-20 – 4-27)Drainage Channels (p.4-20 – 4-27) Pedestrian Facilities (p.4-56 – 4-66)Pedestrian Facilities (p.4-56 – 4-66)

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4.2 Cross Section4.2 Cross Section

2www.Visual Dictionary On-line.com

Roadway vs. Traveled Roadway vs. Traveled WayWay

Roadway: The portion of a highway, including shoulders, for vehicular use. A divided highway has two or more roadways.

Traveled Way: The portion of the roadway for the movement of vehicles, exclusive of shoulders. 3

Roadway Assembly in Roadway Assembly in Civil 3DCivil 3D

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Roadway Assembly (2)Roadway Assembly (2)

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Typical Cross Section Typical Cross Section Normal CrownNormal Crown

High-type surface: 1.5 to 2.0%

Low-type surface: 2 to 6%

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Fig. 4-1

Typical Cross Section Typical Cross Section SuperelevatedSuperelevated

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Fig. 4-2

Roadway Sections for Divided Roadway Sections for Divided HighwayHighway

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Fig. 4-3

4.3 Lane Width4.3 Lane Width 9 to12 ft, 12 ft predominant9 to12 ft, 12 ft predominant 11 ft acceptable11 ft acceptable 9 ft acceptable for low-9 ft acceptable for low-

volume roads in rural & volume roads in rural & suburban areassuburban areas

Narrow inside lanes may be Narrow inside lanes may be OK, like 10 to 11 ft inside OK, like 10 to 11 ft inside lanes and 12 to 13 ft outside lanes and 12 to 13 ft outside lanes to accommodate bikeslanes to accommodate bikes

Auxiliary lanes (like left Auxiliary lanes (like left turn lanes) can be 10 ft, but turn lanes) can be 10 ft, but TWLTL should have 10- to TWLTL should have 10- to 16-ft16-ft

9These values remain the same in HCM 2010.

4.4 Shoulders4.4 Shoulders

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Fig. 4-4

Importance of ShouldersImportance of Shoulders Space for vehicles with problems to parkSpace for vehicles with problems to park Space for drivers to stop and check maps, etcSpace for drivers to stop and check maps, etc Space for evasive maneuvers to avoid collisionsSpace for evasive maneuvers to avoid collisions The sense of opennessThe sense of openness Help providing required sight distanceHelp providing required sight distance Increased aestheticsIncreased aesthetics Improved capacityImproved capacity Space for maintenance operations (snow & Space for maintenance operations (snow &

storage)storage) Lateral clearance for signs and guardrailsLateral clearance for signs and guardrails Discharge storm water away from the edge of Discharge storm water away from the edge of

pavement (reduce pavement breakup)pavement (reduce pavement breakup) Structural support for the pavementStructural support for the pavement Space for pedestrians and bicyclesSpace for pedestrians and bicycles

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4.4.2 Shoulder Width4.4.2 Shoulder Width Desirably, a vehicle stopped on the Desirably, a vehicle stopped on the

shoulder should clear the edge of the shoulder should clear the edge of the traveled way by traveled way by at least 1 ftat least 1 ft, and , and preferably 2 ftpreferably 2 ft. . 10 ft min 10 ft min width (Semi-width (Semi-trailer width is about 8 ft.)trailer width is about 8 ft.)

A minimum of 2 ft for the lowest-type A minimum of 2 ft for the lowest-type highway, and highway, and 6 to 8 ft preferred6 to 8 ft preferred

A minimum of 10 ftA minimum of 10 ft, , preferably 12 ft preferably 12 ft for for high-type high-volume roadshigh-type high-volume roads

A min clearance of 4 ft A min clearance of 4 ft to barriersto barriers A shoulder should be continuousA shoulder should be continuous

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4.4.3 Shoulder Cross 4.4.3 Shoulder Cross SectionSection

Depends on the type of shoulder Depends on the type of shoulder constructionconstruction Bitumen/concrete-surfaced: 2 to 6%Bitumen/concrete-surfaced: 2 to 6% Gravel/crushed-rock: 4 to 6%Gravel/crushed-rock: 4 to 6% Turf: 6 to 8%Turf: 6 to 8%

The max algebraic difference in the The max algebraic difference in the traveled way and shoulder grades traveled way and shoulder grades should be fromshould be from6 to 7% (be careful especially at the higher side of the segments with superelevation (i.e., grade break) And , which values should be used at the

Moark Junction?13

4.4.4 Shoulder Stability4.4.4 Shoulder Stability Paved or stabilized shoulders offer Paved or stabilized shoulders offer

numerous advantagesnumerous advantages1)1) Provision of refuge for vehicles during Provision of refuge for vehicles during

emergencyemergency2)2) Elimination of rutting and drop-off adjacent Elimination of rutting and drop-off adjacent

to the edge of the traveled wayto the edge of the traveled way3)3) Provision of adequate cross slope for Provision of adequate cross slope for

drainage of roadwaydrainage of roadway4)4) Reduction of maintenance, andReduction of maintenance, and5)5) Provision of lateral support for roadway base Provision of lateral support for roadway base

and surface courseand surface course

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4.8 Drainage Channels and 4.8 Drainage Channels and SideslopesSideslopes

Drainage channels should have adequate capacity for the Drainage channels should have adequate capacity for the design runoff, provide for unusual storm water with design runoff, provide for unusual storm water with minimum damage to the highway, and be located and minimum damage to the highway, and be located and shaped to provide a safe transition from the roadway to shaped to provide a safe transition from the roadway to the back slope.the back slope.

Drainage channels include (1) roadside channels in cut Drainage channels include (1) roadside channels in cut sections, (2) toe-of-slope channels to convey the water sections, (2) toe-of-slope channels to convey the water from any cut section to the natural watercourse, (3) from any cut section to the natural watercourse, (3) intercepting channels placed back of the top of cut slopes intercepting channels placed back of the top of cut slopes to intercept surface water, and (4) flumes to carry to intercept surface water, and (4) flumes to carry collected water down steep cut or fill slopes.collected water down steep cut or fill slopes.

(2) Foreslope: 1V:4H or flatter recommended

(5) Backslope: 1V:3H or flatter recommended

(if steeper than 1V:2H, consider retaining walls)15

Fig. 4-6

4.17.1 Sidewalks4.17.1 Sidewalks 8 ft considered an appropriate minimum.8 ft considered an appropriate minimum. In residential areas, 4 to 8 ft.In residential areas, 4 to 8 ft. A planted strip between the traveled-way curb and A planted strip between the traveled-way curb and

sidewalk should be min 2 ft wide for maintenance sidewalk should be min 2 ft wide for maintenance purpose.purpose.

Where sidewalks are placed adjacent to the curb, Where sidewalks are placed adjacent to the curb, make it 2 ft wider than the minimum required when make it 2 ft wider than the minimum required when they are placed with a planted strip.they are placed with a planted strip.

In general, wherever roadside and land development In general, wherever roadside and land development conditions affect regular pedestrian movement along a conditions affect regular pedestrian movement along a highway, a sidewalk or path area, as suitable to the highway, a sidewalk or path area, as suitable to the conditions, should be furnished.conditions, should be furnished.

As a general practice, sidewalks should be constructed As a general practice, sidewalks should be constructed along any street or highway not provided with along any street or highway not provided with shoulders, even though pedestrian traffic may be light.shoulders, even though pedestrian traffic may be light.

Sidewalks should have all-weather surface to ensure Sidewalks should have all-weather surface to ensure their intended use.their intended use. 16

US 89 Cross SectionUS 89 Cross Section

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Google Earth: Street Google Earth: Street ViewView

18South of Moark Junction US6, Looking west

North of Moark JunctionUS89, Looking north

North of Moark JunctionUS6, Looking east

North of Moark Junction, near 2nd SouthUS89, Looking north

4.17 Pedestrian Facilities4.17 Pedestrian Facilities

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Complete Street DesignComplete Street Design

http://www.completestreets.org/complete-streets-fundamentals/

Complete Streets are streets for everyone. They are designed and operated to enable safe access for all users. Pedestrians, bicyclists, motorists, and public transportation users of all ages and abilities are able to safely move along and across a complete street. Complete Streets make it easy to cross the street, walk to shops, and bicycle to work. They allow buses to run on time and make it safe for people to walk to and from train stations.

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Urban Milwaukee Urban Milwaukee MakeoverMakeover

(South 2(South 2ndnd Street) Street)

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Daybreak, UtahDaybreak, Utah

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