Accessible Pedestrian Signals

Presented by:

Joe Couples, P.E.

Valerie Lee, P.E.

Legacy devices remain...but mostly new technology.

Seattle APS

Accessible Pedestrian Signals(APS)

MUTCD 4E.06• Both audible and vibro-tactile modes

identified for walk indication.• Locator tone identified in support section.• Provides guidance for factors that should

be considered in study of when to install an Accessible Pedestrian Signal.

• APS cannot be by TOD operation.

Study Factors to Consider

• Potential demand (needs) for APS.• Requests.• Traffic Volumes, and turning movements.• Signal complexity.• Intersection complexity

Potential Demand

• High Volume Transit facilities such as Streetcar and LRT stations.

• Transit hubs and transfer points.• Libraries or other facilities for the blind.• Recreation facilities.

Requests

In Seattle:• Until LINK Light Rail and the South Lake

Union Streetcar, almost all of the APS installations were based upon requests.

• Almost all requests were to meet transit, shopping, and employment needs of individual(s).

Traffic Volumes

• Pedestrians may be present at any time.• Low Volumes.• High turning volume percentage.

Traffic Signal Complexity

• Split-Phasing.• Protected Left or Right-Turns.• Leading Pedestrian Intervals (LPI).• Exclusive pedestrian phase.• Other complicated signal operation.

Split Phasing

Intersection Complexity

• Skewed intersection geometry.• Median islands.• Free right-turn islands.• Signal complexity.• Intersection complexity

Intersection Skew

Traffic island

APS Design Best Practice

Design Complications

• Underground utilities, MH & JB's.• Curb ramps.• Decorative poles.• Light and heavy rail adjacent or in ROW.

Design Complications

Median Island APS

Over-Engineering?

Errors or Design Standards?

Which is Correct?

Office Engineering?

APS in Operation

• Actuated operation.• Pre-timed/recall operation.• APS Controller Unit.

Actuated Operation

• Pedestrian pushes button to activate.• Audible and vibro-tactile activate with

“Walk” indication.• Returns to holding mode with “ Flashing

Don't Walk”.

Pre-timed Operation in Seattle

• “Walk” interval comes on automatically without the audible & vibro-tactile.

• Some devices able to activate audible & vibro-tactile if adequate clearance time.

• Returns to holding mode with “ Flashing Don't Walk”, PBS indicator light goes on.

APS Settings

• Locator tone is used.• Audible and locator tone volume settings

are independently adjustable.• Volume adjusts to ambient noise so as to

be quieter at night and other periods.

Noise Complaints

• Few complaints regarding audible indications.

• Complaints regarding audible mostly by multi-story condo or apartment dwellings.

• Many complaints regarding locator tone in residential areas.

APS Prioritization

Post InstallationCheck List

APS Sign Message

Web Resources

• NCHRP Web Document 117A, Accessible Pedestrian Signals: A Guide to Best Practices. June 2007

• MUTCD 2009

Questions?