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

Revision to the AASHTO Guide for the Development of Bicycle Facilities

Presentation by:

Jennifer ToolePrincipal Investigator

July 21st, 2009

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

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

Project Timeline

NCHRP Project Completion – Fall 2009

• 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.

Basis for Content Changes

Issues NOT addressed by this Guide

• Contrasting colored pavements• Bike boxes• Cycle tracks• Raised bike lanes• Bicycle signal heads

Important source for design chaps

New Chapter

Bicycle 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.

Key Dimensions Chart

User Type FeatureUS Cust Metric

Typical upright adult bicyclist Physical Width (95th percentile) 30 in 0.75 mPhysical length 70 in 1.8 mPhysical height of handlebars (typ dimension) 44 in 1.1 mEye height 60 in 1.4 mCenter of Gravity (approximate) 33-40 in 0.8-1.0 mOperating width (minimum) 48 in 1.2 mOperating width (preferred) 60 in 1.5 mOperating height (minimum) 100 in 2.5 mOperating height (preferred) 120 in 3.0 m

Recumbent bicyclist Physical length 82 in 2.2 mEye height 46 in 1.2 m

Tandem bicyclists Physical length (typical dimension) 96 in 2.4 mBicyclist with child trailer Physical width 30 in 0.75 m

Physical length 117 in 3.0 mHand bicyclist Eye height 34 in 0.9 mInline skater Sweep width 60 in 1.5 m

Dimension

Chapter 4

Design 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

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)

Shared Lane Markings

• Coordinated with MUTCD

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

Climbing Lanes

Where NOT to use SLM’s

• On paved shoulders or bike lanes• Where the speed limit exceeds 35 mph

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

Bicycle Lanes

• Markings are required, but signs are optional

• More guidance for markings at bus stops

• Both symbols still allowed

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

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)

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

Typical bike lane markings

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

Bicycle Guide Signs

M1-8 and M1-9 Series

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.

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

Detection for Bikes at Signals

• Provides more guidance on:– Loop configurations that

best detect bicycles– Sensitivity settings– Use of upstream detectors– Detector markings

Roadway Bridges

• Bridges should accommodate bicycles• “Absence of bicycle accommodations on the

approach should not prevent the accommodation of bicycles on the bridge.”

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.

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

Single Point Urban Interchange

Merge Ramp Options

Merge Ramp Options

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

Multi-lane Roundabouts

Chapter 5

Design 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

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

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

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

Safety rail

guidelines

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

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)

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

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

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

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

Example Yield Control for Path

Example Stop Control for Path

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

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

New Chapter

Bicycle Parking

• Planning for bicycle parking• Short-term bicycle parking

– Location– Design– Special types of racks

• Long-term bicycle parking

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

Thank you!

Contact information:

Jennifer TooleToole Design Group

[email protected]