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Traffic Light Yellow Times Not Long Enough

Date: 2014-07-13
Tags: pittsburgh traffic-lights transportation walkability

I went back to school for Transportation Engineering because I feel that by making places more accessible, I can help improve people’s lives. One such way I feel that I can help, is by advocating for safe conditions for pedestrians. In one of my first attempts to use what I’ve learned, I’ve written a letter to my city council representetive:

On my walks to work, I’ve noticed that a bunch of intersections on Centre Ave and Baum Blvd do not have clear-times (the sum of the Yellow and All-Red phases at a traffic signal) that are sufficent to allow pedestrians to cross safely. Numerous times I’ve been caught in the middle of one of these roads, and I’m a quick walk — doubly so when comparied to an elderly or disabled person.

The Manual of Uniform Traffic Control Devices &sec; 4E.06.07 provides guidance to use 3.5 feet per second as the walking speed of a pedestrian.

The MUTCD &sec; 4D.04.04.A.3 states that “Pedestrians facing a CIRCULAR GREEN signal indication, unless otherwise directed by a pedestrian signal indication or other traffic control device, are permitted to proceed across the roadway within any marked or unmarked associated crosswalk.”

The MUTCD &sec; 4D.04.03.B.3 states that “Pedestrians facing a steady CIRCULAR YELLOW or YELLOW ARROW signal indication, unless otherwise directed by a pedestrian signal indication or other traffic control device shall not start to cross the roadway.”

My measurements are as follows

Intersection Clearance Time Crosswalk length Suggested Safe Crossing Time
Centre @ Liberty 6 s 55ft 16s
Liberty @ Center 6 s 57ft 17s
Centre @ Graham 6 s 30ft 9s
Graham @ Centre 6 s 30ft 9s
Baum @ Graham 6 s 60ft 18s
Graham @ Baum 6 s 80ft 22s
Baum @ Aiken 6 s 55ft 16s
Aiken @ Baum 6 s 60ft 18s
Baum @ Liberty 6 s 70ft 20s
Liberty @ Baum 6 s 86ft 25s

None of these intersections are anywhere near the amount of time required to cross them by a healthy adult, let alone an elderly or disabled person. Especially given that efforts are being done on Baum Blvd to install microwave sensors to aid traffic flow, steps should be taken to ensure that pedestrians are given the proper amount of time when crossing.

Installing Pedestrian Signals (PedHeads), would provide feedback to pedestrians as to the amount of time remaining for them to begin safely crossing. This option has no affect on traffic or intersection geometry and doesn’t require retiring the signaling system. I would strongly urge you to have Public Works audit this corridor in order to determine the exact need and configuration of pedestrian signals.

This corridor is also home to a hospital and two hotels which attract many non-locals, who are not familiar with the configuration of these intersection. Even as a local, I find myself many times a week caught in the middle of the road needing to sprint to exit the roadway after opposing traffic is given a green light.

Additionally, Liberty at Baum has a leg of the intersection closed to pedestrian crossings. I believe that this is a terrible thing to do, not the least of which is because pedestrians have a habit of crossing at intersections regardless of being told not to. Additionally, to legally cross this intersection now requires waiting through 2 additional phases of the traffic signal — adding a noticeable amount of time to someone just wanting to stroll to a diner or restaurant a little further down the block. Moreover, it is extremely rude and unfriendly to pedestrians, who may be visitors to our city, to tell them that an intersection that is visibly clear and poses no immediate threat, is closed — it reflects very poorly on city trying to build a pedestrian and bike friendly image. I would also urge you to have Public Works consider removing this closure, especially if PedHeads are to be installed as it will provide reliable feedback to pedestrians on how long they have left to cross this intersection.

Thank you for your time regarding this issue. I believe that little things such as providing pedestrians reliable information on how long they have to cross an intersection go a very long way in increasing the safety, usability, and pleasantness of walking around.


Jim Keener