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Revision to the AASHTO Guide for the Development of Bicycle Facilities

Revision to the AASHTO Guide for the Development of Bicycle Facilities

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Revision to the AASHTO Guide for the Development of Bicycle Facilities

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  1. Revision to the AASHTO Guide for the Development of Bicycle Facilities Presentation by: Jennifer Toole Principal Investigator July 21st, 2009

  2. NCHRP Project 15-37 • Some history • This will be the 4th edition of the Guide • Last Guide – 1999, largely written in 96-98 • John LaPlante and Jennifer Toole – co-authors • Survey to update Guide – 2004 • Chair of NCHRP Panel – Dwight Kingsbury, Florida DOT • Panel includes: • 7 members from State DOTs • 2 FHWA representatives • 3 members from local agencies • 1 consultant

  3. Team and Panel Project Team • Jennifer Toole, Principal Investigator • Eric Mongelli, P.E. • William Schultheiss, P.E. • Nick Jackson • Subject Matter Experts: • John LaPlante, P.E., PTOE • Michael Moule, P.E. • Michael Ronkin • Mia Birk • Matthew Ridgeway • Shawn Turner, P.E. • Srinivasa Sunkari, P.E. • Bill Hunter Panel • Dwight Kingsbury, Chair • Denise Chaplick • David Church, P.E. • Ann Do • Eric Glick • Fred Glick, RLA • Thomas Huber • Mary Meletiou • Richard Moeur, P.E. • William Prosser, P.E. • William Riccio, Jr., P.E. • Cara Seiderman • Richard Pain

  4. Project Timeline • NCHRP Project Completion – Fall 2009

  5. Basis for Content Changes • Reviewed findings of scoping study (survey) • Reviewed a significant body of research and literature • Drew upon our own experience using the Guide on a daily basis • Drew upon the experience of our Team and Panel • This presentation will cover the highlights of new and revised content of design chapters.

  6. Issues NOT addressed by this Guide • Contrasting colored pavements • Bike boxes • Cycle tracks • Raised bike lanes • Bicycle signal heads

  7. Important source for design chaps

  8. New ChapterBicycle Operation and Safety • Sets the stage for Design Chapters • Organizes info on design vehicle • Overview of traffic principles for bicycles • Positioning on the roadway in different situations • Causes of bicycle crashes • Urban vs. rural • Young vs. adult riders • Etc.

  9. Key Dimensions Chart

  10. Chapter 4Design of On-Road Facilities • More guidance on shared lanes, general roadway compatibility • New sections on shared lane markings, bicycle boulevards and wayfinding signage • More context and detail for bike lane guidance • More info on bike lanes with various roadway configurations • More info on bike lanes at intersections • New section on retrofitting existing roadways to accommodate bicycles

  11. Shared Lanes • Roads do not need a special bicycle facility to be compatible • Design guidance for wide outside lanes is same (14’) • Guidance on selecting appropriate type of bikeway given traffic volumes and speeds (Bicycle LOS)

  12. Shared Lane Markings • Coordinated with MUTCD

  13. Locations to use SLM’s • Adjacent to on-street parking to position cyclist outside of door zone • In wide lanes to position away from curb • Narrow lanes • Multi-lane roads where there is no room for bike lane • Climbing lanes (on downgrade) paired with bike lane

  14. Climbing Lanes

  15. Where NOT to use SLM’s • On paved shoulders or bike lanes • Where the speed limit exceeds 35 mph

  16. Paved Shoulders • Shoulder width: • 4 ft. min, 5 ft against vertical face • Wider if there are higher speeds/volumes (per BLOS) • At shoulder bypass lanes – carry shoulder space through T-intersections

  17. Bicycle Lanes • Markings are required, but signs are optional • More guidance for markings at bus stops • Both symbols still allowed

  18. Left-Side Bicycle Lanes • Discussion of when left side bike lanes can be beneficial on one-way streets: • When there are a lot of left-turning bicyclists • If the left-side lane would decrease conflicts, i.e. with buses or heavy right turn volumes

  19. Bicycle Lane Widths – DRAFT • Same as last Guide – 5 ft standard width (4 ft with no curb and gutter) • Some caveats: • 5 ft bike lane is sufficient assuming a 1 ft wide gutter • In states that use a 2 ft wide gutter, a 6 ft wide bike lane is preferred, with 5 ft as a minimum width in locations with lower speeds • In extremely constrained, urban low speed environments where 5 ft cannot be achieved and there is no gutter, a 4 ft wide bike lane is acceptable (assumes adjacent travel lane has been narrowed to the minimum acceptable width)

  20. Angled Parking • Bike lanes not recommended at front-in angled parking • Bike lanes are OK with back-in angled parking if parking bays are sufficient length

  21. Typical bike lane markings

  22. Bicycle Guide Signs • Deemphasizes bike routes, they are not a facility type • Guidance on all sign types • Signs are not a substitute for good geometric design • D-Series are below

  23. Bicycle Guide Signs

  24. M1-8 and M1-9 Series

  25. Traffic Signals • Significantly expanded guidance • Formulas and diagrams based on new data • Assumes one speed – 10 mph – rather than different speeds for A, B and C bicyclists • Appropriate to modify the minimum green interval, all-red interval, and extension time for bicyclist speeds.

  26. Bicycle Minimum Green • Bicyclists require more time to clear intersection than motorists • More important where minor streets cross major roads (may be a long distance with a short cycle length) • Two choices: • Program controller to provide BMG with a detector • Increase minimum green for all vehicles

  27. Detection for Bikes at Signals • Provides more guidance on: • Loop configurations that best detect bicycles • Sensitivity settings • Use of upstream detectors • Detector markings

  28. Roadway Bridges • Bridges should accommodate bicycles • “Absence of bicycle accommodations on the approach should not prevent the accommodation of bicycles on the bridge.”

  29. Bridge Railings • In locations where bicyclists will operate in close proximity to railings, should be a minimum of 42” high. • On bridges where bicycle speeds are likely to be high and where a bicyclist could impact a barrier at a 25 degree angle or greater, use 48” railing.

  30. Bicycles on Freeways • Addresses considerations if bicycles are allowed to operate on the freeway • Addresses freeway interchange design • Design junctions as right-angle intersections if possible

  31. Single Point Urban Interchange

  32. Merge Ramp Options

  33. Merge Ramp Options

  34. Bicycles at Roundabouts • Terminate bike lanes in advance (at least 100 ft) • General design issues • Low speed roundabouts are best (15-20 mph) • Discourages use of multi-lane roundabouts unless absolutely necessary • For multi-lane roundabouts, provide opportunity for bicyclist to exit roadway and use sidewalk

  35. Multi-lane Roundabouts

  36. Chapter 5Design of Shared Use Paths • New stand-alone chapter • Reflects several significant studies: • Characteristics of Emerging Trail and Roadway Users • Shared Use Path Level of Service • Architectural Barriers Act Accessibility Guidelines for Outdoor Developed Areas • Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled Locations • Fills missing gaps in the old Guide

  37. Sidepath Guidance • Consolidates discussion of SUP’s adjacent to roadways – Clearly defines “sidepath” • Expands discussion of operational problems • Acknowledges reasons for building paths adjacent to roadways • Provides guidance on when and where these facilities are appropriate • Provides design guidance for those locations

  38. Sidepaths may be considered: • Adjacent road has high speeds and volumes and no practical alternatives for improving on-road conditions or adjacent routes • Sidepath is used for a short distance to connect: • Pathway segments • Local streets used as bicycle routes • Sidepath can be built with few roadway and driveway crossings • Sidepath can be terminated in a bicycle compatible location

  39. Shoulders/clearances • Graded shoulder of 3-5 ft recommended, max cross slope of 1:6 • Minimum clearance of 2 ft to lateral obstructions • Except at smooth features such as railings or fences, 1 ft is acceptable • Adjacent to hazards, 5 ft separation is desired • Water hazards • Downward slopes greater than 3:1 • Depending on height of embankment and condition at bottom, railing may be needed

  40. Safety rail guidelines

  41. Design Speed • Old Guide: 20 mph min design speed • New Guide: “No single design speed” for all paths • Consider types of users, terrain, path surface • Guidelines: • Generally should not be lower than 85th percentile speed: 14 mph • For longer segments in flat areas: 18 mph • Higher design speeds in hilly terrain, up to 30 mph

  42. Horizontal Alignment • Horizontal curve formula is now based on lean angle rather than superelevation • By revising formulas and using new design speeds, min. curve radius can be lower: • Old Guide: 90-100 ft min • New Guide: 60 ft (18 mph design speed)

  43. Speed Control on Paths • Introduces concept of using geometric design and traffic control to reduce user speeds, such as curvature • Recommends centerline stripe to reduce speeds and address conflicts • Depends on site specific context

  44. Stopping Sight Distance • New braking friction factor for bikes (0.16) • Longer stopping distances but reduced design speed offsets this • Gives values for other users

  45. Path-Roadway Intersections • Significantly expanded guidance • Explains the complexities of path-roadway intersections: • Fastest user must be considered on the approach • Slowest user must be considered at the crossing • Three intersection types: • Midblock • Sidepath • Grade-separated