clear passage.
GEOMETRIC DESIGN
Advisory Shoulder Recommendations
Figure 2-9. Advisory shoulders clarify positioning and yield priority on roads too narrow to provide exclusive travel space. When pedestrians or bicyclists are present, motorists may need to yield to users present in the advisory shoulder before passing. Note - Advisory shoulders are not specifically identified in the comprehensive network recommendations. Both yield roadways and advisory shoulders can be helpful treatments in situations where there may be major constraints (physically or financially) in implementing a better facility (ie: sidewalk). Yield roadways and advisory shoulders, in the appropriate context, can be utilized as nearer-term treatments to tilt a particular roadway toward a more pedestrian friendly environment. ADVISORY SHOULDER The advisory shoulder space is a Advisory shoulder designs work best on road segments without frequent stop or signal controlled intersections that require vehicles to stop within the roadway. The designer should strive to maintain the visual definition of the advisory shoulder through all driveways and street crossings, and provide a conventional shoulder at controlled intersections. An approved Request to Experiment is required to implement Advisory Shoulders, called “dashed bicycle lanes” in the FHWA experimentation process. For more information on the experimentation process, visit http://mutcd.fhwa.dot.gov/. Unlike a conventional shoulder, an advisory shoulder is a part of the traveled way, and it is expected that vehicles will regularly encounter meeting or passing situations where driving in the advisory shoulder is necessary and safe, as illustrated in Figure 2-9 . visually distinct area on the edge of the roadway, offering a prioritized space for people to bicycle and walk. • The preferred width of the advisory shoulder space is 6 ft (2.0 m). Absolute minimum width is 4 ft (1.2 m) when no curb and gutter is present. TWO-WAY CENTER TRAVEL LANE The two-way center travel lane is created from the remaining paved roadway space after the advisory shoulder has been accounted for. • Preferred two-way center travel lane width is 13.5–16 ft (4.1–4.9 m) although may function with widths of 10–18 ft (3.0–5.5 m). Table 2-2 describes the impacts of various center lane widths on roadway operations. Advisory Shoulder 6 ft (1.8 m) preferred Center Two-Way Travel Lane 10–18 ft (3.0–5.5 m) • Consider using contrasting paving materials between the advisory shoulder and center travel lane to differentiate the advisory shoulder from the center two-way travel lane in order to minimize unnecessary encroachment and reduce regular straddling of the advisory shoulder striping.
Advisory shoulders clarify positioning and yield priority on roads too narrow to provide exclusive travel space. When pedestrians or bicyclists are present, motorists may need to yield to users present in the advisory shoulder before passing.
Application Speed and Volume
preferred potential
12k
10k
8k
6k
4k
2k
A
10
20 30 40 50
MOTOR VEHICLE OPERATING SPEED (MI/H)
ADVISORY SHOULDER The advisory shoulder space is a visually distinct area on the edge of the roadway, offering a prioritized space for people to walk (and bike). • The preferred width of the advisory shoulder space is 6 ft (2.0 m). Absolute minimum width is 4 ft (1.2 m) when no curb and gutter is present. • Consider using contrasting paving materials between the advisory shoulder and center travel lane to differentiate the advisory shoulder from the center two-way travel lane in order to minimize unnecessary encroachment and reduce regular straddling of the advisory shoulder striping. TWO-WAY CENTER TRAVEL LANE The two-way center travel lane is created from the remaining paved roadway space after the advisory shoulder has been accounted for. • Preferred two-way center travel lane width is 13.5–16 ft (4.1–4.9 m) although may function with widths of 10–18 ft (3.0–5.5 m). See the table on the following page that describes the impacts of various center lane widths on roadway operations.
Network Applies to constrained connections between built up areas.
Figure 2-10. Motorists travel in the center two-way travel lane. When passing a bicyclist, no lane change is necessary. Advisory Shoulder
Figure 2-11. When two motor vehicles meet, motorists may need to encroach into the advisory shoulder space.
2-19
Table 2-2. Interactions when vehicles traveling in opposite directions meet by two-way center turn lane width. Interactions when vehicles traveling in opposite directions meet by two-way center turn lane width.
HIGHWAY LOCAL COLLECTOR
Two-Way Center Travel Lane Width
Impact on Advisory Shoulder Encroachment When Vehicles Traveling in Opposite Directions Meet Requires vehicle encroachment into the advisory shoulder space when vehicles traveling in opposite directions meet. Two passenger cars are physically able to meet each other within the center lane at very low speed. In practice, vehicles will encroach into the advisory shoulder.
10 ft (3.0 m)
B Practical minimum width
For use outside, between, and within built up areas with bicycle and pedestrian demand and limited available paved roadway surfaces. Land Use
13.5 ft (4.5 m)
C Preferred minimum width
Preferred maximum width
16 ft (4.9 m)
Permits two passenger cars to pass within the center lane at modest speeds without encroaching into the advisory shoulder.
18 ft (5.5 m)
This width is equivalent to two 9 ft (2.7 m) travel lanes and regular encroachment into the advisory shoulder space may not be necessary.
D Absolute maximum width
10 ft (3.0 m) Center Travel Lane Further information on Advisory Shoulders can be found in the FHWA Small Town and Rural Multimodal Networks guide: http://ruraldesignguide.com/ 13.5 ft (4.5 m) Center Travel Lane Implementing agencies should be advised that the above dimensional guidance is intended to facilitate implementation on common roadway widths in the U.S. As with most treatments, more overall width is preferable to constrained circumstances. 18 ft (15.5 m) Center Travel Lane
B
C
D
96
97
APPENDIX A: DESIGN GUIDANCE
FUQUAY-VARINA PEDESTRIAN PLAN
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