Title: Revision to the AASHTO Guide for the Development of Bicycle Facilities
1Revision to the AASHTO Guide for the Development
of Bicycle Facilities
- Presentation by
- Jennifer Toole
- Principal Investigator
- July 21st, 2009
2NCHRP 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
3Team 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
4Project Timeline
- NCHRP Project Completion Fall 2009
5Basis 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.
6Issues NOT addressed by this Guide
- Contrasting colored pavements
- Bike boxes
- Cycle tracks
- Raised bike lanes
- Bicycle signal heads
7Important source for design chaps
8New 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.
9Key Dimensions Chart
10Chapter 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
11Shared 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)
12Shared Lane Markings
13Locations 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
14Climbing Lanes
15Where NOT to use SLMs
- On paved shoulders or bike lanes
- Where the speed limit exceeds 35 mph
16Paved 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(No Transcript)
18Bicycle Lanes
- Markings are required, but signs are optional
- More guidance for markings
at bus stops - Both symbols still allowed
19Left-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
20Bicycle 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)
21Angled 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
22Typical bike lane markings
23Bicycle 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
24Bicycle Guide Signs
25M1-8 and M1-9 Series
26Traffic 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.
27Bicycle 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
28Detection for Bikes at Signals
- Provides more guidance on
- Loop configurations that
best detect bicycles - Sensitivity settings
- Use of upstream detectors
- Detector markings
29Roadway Bridges
- Bridges should accommodate bicycles
- Absence of bicycle accommodations on the
approach should not prevent the accommodation of
bicycles on the bridge.
30Bridge 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.
31Bicycles 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
32Single Point Urban Interchange
33Merge Ramp Options
34Merge Ramp Options
35Bicycles 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
36Multi-lane Roundabouts
37Chapter 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
38Sidepath 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(No Transcript)
40Sidepaths 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
41Shoulders/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
42Safety rail guidelines
43Design 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
44Horizontal 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)
45Speed 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(No Transcript)
47(No Transcript)
48(No Transcript)
49Stopping Sight Distance
- New braking friction factor for bikes (0.16)
- Longer stopping distances but reduced design
speed offsets this - Gives values for other users
50Path-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
51Mid-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
52Example Yield Control for Path
53Example Stop Control for Path
54Design 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
55Design 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
56New ChapterBicycle Parking
- Planning for bicycle parking
- Short-term bicycle parking
- Location
- Design
- Special types of racks
- Long-term bicycle parking
57Next 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
58Thank you!
- Contact information
- Jennifer Toole
- Toole Design Group
- jtoole_at_tooledesign.com