Revision to the AASHTO Guide for the Development of Bicycle Facilities - PowerPoint PPT Presentation

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Revision to the AASHTO Guide for the Development of Bicycle Facilities

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Title: Revision to the AASHTO Guide for the Development of Bicycle Facilities


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 SLMs
  • 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 SLMs
  • 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
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18
Bicycle Lanes
  • Markings are required, but signs are optional
  • More guidance for markings
    at bus stops
  • Both symbols still allowed

19
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

20
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)

21
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

22
Typical bike lane markings
23
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

24
Bicycle Guide Signs
25
M1-8 and M1-9 Series
26
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.

27
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

28
Detection for Bikes at Signals
  • Provides more guidance on
  • Loop configurations that
    best detect bicycles
  • Sensitivity settings
  • Use of upstream detectors
  • Detector markings

29
Roadway Bridges
  • Bridges should accommodate bicycles
  • Absence of bicycle accommodations on the
    approach should not prevent the accommodation of
    bicycles on the bridge.

30
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.

31
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

32
Single Point Urban Interchange
33
Merge Ramp Options
34
Merge Ramp Options
35
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

36
Multi-lane Roundabouts
37
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

38
Sidepath Guidance
  • Consolidates discussion of SUPs 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

39
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40
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

41
Shoulders/clearances
  • Graded shoulder of 3-5 ft recommended, max cross
    slope of 16
  • 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 31
  • Depending on height of embankment and condition
    at bottom, railing may be needed

42
Safety rail guidelines
43
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

44
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)

45
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

46
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47
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48
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49
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

50
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

51
Mid-Block Intersections
  • Geometric design issues
  • Special issues with assignment of right-of-way
  • Determining appropriate crossing measures
  • Determining priority assignment
  • Routine use of stop signs
  • Evaluating sight distance and selecting type of
    control
  • Midblock signalized intersections
  • Examples

52
Example Yield Control for Path
53
Example Stop Control for Path
54
Design at Sidepath Intersections
  • Based on Florida DOT research
  • Reduce turning speeds at driveways and
    intersections tighter corner radii, avoid
    free-flowing movements, provide median refuge
    islands, carry path surface across driveway, etc.
  • Reduce frequency of driveways
  • Consider design to reduce path user speeds
  • Employ measures on adjacent road to reduce speeds

55
Design at Sidepath Intersections
  • Facilitate bicycle movements to/from road to
    pathway
  • Keep crossings clear of obstructions
  • Add stop or yield bars to instruct drivers
    crossing pathway
  • Design path termini to ensure proper operation of
    bicyclists entering roadway

56
New ChapterBicycle Parking
  • Planning for bicycle parking
  • Short-term bicycle parking
  • Location
  • Design
  • Special types of racks
  • Long-term bicycle parking

57
Next up AASHTO Ped Guide!
  • NCHRP 20-7, Task 263
  • Opinion Survey OPEN TILL JULY 31
  • http//tinyurl.com/AASHTO-Ped-Guide
  • Includes a literature review
  • Project concludes in October
  • Will provide an annotated outline for the next
    Guide

58
Thank you!
  • Contact information
  • Jennifer Toole
  • Toole Design Group
  • jtoole_at_tooledesign.com
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