PUFFIN Crossing

Tucson, Arizona
Source: Pedestrian and Bicycle Information Center (PBIC)


Pedestrians crossing multilane roadways face a number of serious challenges, especially those pedestrians who have difficulty walking. Even at locations where a crosswalk signaling device is available, the crossing time might not last long enough to allow the pedestrian to complete the crossing during the standard allotted time.


Example of an automated pedestrian sensor used in Bristol, United Kingdom. Image source: http://www.international.fhwa.dot.gov/pubs/pl10010/pl10010.pdf

Transportation engineers in Great Britain were the first to tackle this problem and created the PUFFIN signal as a way to accommodate slower pedestrians at crosswalks. PUFFIN stands for Pedestrian User-Friendly Intelligent Intersection, and it uses active detection and passive presence of pedestrians in crosswalks to determine whether the pedestrian phase of a traffic signal or beacon should be extended or canceled. PUFFIN signals in Great Britain reduce waiting times for both pedestrians and motorists while making sure that slower pedestrians can safely cross the street. PUFFIN signal indications are often placed on the near side of an intersection so that pedestrians can view oncoming traffic and look at the signal simultaneously. This positioning of the signals so crossing pedestrians can no longer see their signal has caused some concern in Great Britain and is currently under study. Tucson has attempted to take the best from the British design and overcome the position of the pedestrian signal indication issues with the Tucson PUFFIN. The pedestrian indications are placed so they are visible throughout the crossing maneuver in Tucson.

Tucson, Arizona, has a large percentage of residents over 65 years of age. Many of these mature residents still desire to be mobile but they can no longer drive. The City of Tucson has provided a modern transit system to facilitate their travel needs. Further, the City was concerned about enabling residents to safely cross its streets, especially at transit stops. One crosswalk at 8200 East Broadway Boulevard in Tucson was located adjacent to a retirement community. Broadway is a six-lane divided arterial with priority transit lanes and a posted speed limit of 40 mi/h, which increased the likelihood that some pedestrians would need more than the normal allotted time for crossing a roadway of its width.


Driver’s view of a HAWK beacon at the University of Arizona in Tucson.

The crosswalk markings and median island at 8200 East Broadway Boulevard were not considered satisfactory enough to assist crossing pedestrians, and the location was not appropriate for a traffic signal. To fix the problem, the City installed a HAWK beacon with PUFFIN detector logic at the mid-block crossing. HAWK stands for High Intensity Activated Crosswalk, and it consists of two red lights situated above a yellow light. HAWK beacons are now known as Pedestrian Hybrid Beacons.

The HAWK beacon is normally dark, like a railroad signal. When a pedestrian activates a HAWK beacon, the signal flashes yellow, displays a solid yellow, and then changes to a solid red for the motorists, at which time a WALK indication is displayed to the pedestrian. The solid red indication is followed by a flashing red indication. At the solid red indication, pedestrians can start crossing the roadway. During the alternating flashing red indication, motorists must stop, but they may proceed through the crosswalk after stopping if the pedestrians are out of harm's way. HAWK beacons have been very successful at getting motorists to yield to pedestrians in crosswalks. FHWA studies of HAWK beacons have reported a 97 percent driver yielding compliance.

PUFFIN crossings with the pedestrian sensor circled in red.

The City installed a modified HAWK signal equipped with PUFFIN logic at 8200 East Broadway Boulevard in 2003. The PUFFIN and HAWK beacons in Tucson look identical to the driver and the pedestrian with the only difference being the change in the pedestrian detection logic. With the PUFFIN beacon, if the pedestrian needed more time to cross East Broadway Boulevard, the signal sensed it and lengthened the HAWK's red indication. The normal crossing time was set in accordance with the Manual on Uniform Traffic Control Devices (MUTCD). The upper limit for the extended crossing time was set using a rate of approximately 3 ft per second. This upper limit was determined to assist 95 to 98% of all crossing pedestrians.

Tucson funded the HAWK and PUFFIN beacons with a Regional Transportation Authority ½ cent sales tax. Voters passed the sales tax in 2006 under category #37 - Elderly and Pedestrian Safety Improvements. The cost of the beacons varied depending on location, but it ranged from 80,000 to 150,000 dollars.


Effectiveness of Crossing Devices, FHWA Study (TTI)

The HAWK signals increased yielding compliance rates and improved pedestrian safety. At crosswalks using the standard HAWK beacon, FHWA studies showed a 70 percent reduction potential in pedestrian crossing crashes and a 29 percent reduction potential for all crashes. Overall, the reception of the crosswalk at East Broadway Boulevard has been very positive. The AARP and the ITE recognized the crossing for its pedestrian safety improvements. As of June 2012, the City has installed 114 HAWK beacons and 2 PUFFIN beacons, and approximately two to three dozen more beacons are scheduled to be installed in the future.


Richard Nassi, P.E., Ph.D.
Traffic Engineering (CA0344)
City-County Public Works, 3rd Floor
201 N. Stone
Tucson, AZ 85701
Phone: (520) 791-4259
Email: Richard.Nassi@tucsonaz.gov

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