Today we're featuring R. Moses' answers to two questions about pedestrian crossings:

RRFB signal (Photo by PJ R)

RRFB signal (Photo by PJ R)

Question #1:

Dear Mr. Moses,

In my area, crosswalks with rectangular rapid flashing beacons (RRFBs) are showing up on neighborhood arterial roads. These signals are pretty much ignored by drivers. On the rare occasion that a driver stops, oncoming traffic often doesn't, making the crossing more hazardous than just having paint on the ground. I've even seen comments on a neighborhood Facebook page that pedestrians are legally obligated to wait for a gap in traffic to hit the button and cross, even with these signals. 

What evidence would it take to convince the engineers to put in HAWK signals instead?

R. Moses Answers:

There are not very clear guidelines on use of RRFBs vs HAWKs, but no matter the type of crossing signals, any measures to reduce the speeds and change the expectations and behavior of drivers so that they expect pedestrians would be helpful. Can the number of travel lanes be reduced? Can turning lanes be eliminated to reduce the crossing distances? Can lanes be narrowed to reduce speeds? Can on-street parking be allowed to change the character of the corridor and reduce speeds? Both RRFB’s and HAWKs are imperfect substitutes for creating a context in which drivers proceed with due caution and respect for pedestrians.

Unfortunately, on the typical road, drivers are used to no signal so they don’t slow down. They didn’t have to yesterday so why should they today? Pedestrians then don’t use the signal because drivers don’t slow down. Regular, signaled crossings are too far away to be used comfortably, so people don’t walk at all. Yes, the community medical center may be on one side of the street and apartments on the other, but the perception is rightfully true that it is safer and quicker to drive than it is to walk...

I think that mid-block crossings, HAWK signals, and other such add-ons are attempts to fix a bad design. The bottom line is the street/stroad was designed wrong and flashing lights are not going to fix it, nor will a plethora of pedestrian crossing signs. One solution that I like, although it may be a bit dangerous, is to have everyone use the unsignaled mid-block crossing and not use the signaled intersection/crossing. The cars stop at red lights. If you get enough people in the crossings, drivers will learn to stop, or take another route. Take back the streets.

HAWK signal (Image by KJ Burns)

HAWK signal (Image by KJ Burns)

Question #2

Dear Mr. Moses,

In my town, there is a modest two-lane arterial street I use frequently. Near an elementary school, there is a crosswalk to help kids cross this street. It has an overhead crosswalk sign and yellow flashing lights to warn motorists and help pedestrians cross safely.  The yellow lights are activated at the side of the road, but rather than a button for pedestrians to push, it's activated by a key. The crossing guards are equipped with a key so they can use it during the start and end of the school day.

Why would the city go to the expense to install the overhead warning lights and then go to greater expense to actively prevent pedestrians from using it?


Unfortunately, the initial and faulty assumption was probably that this intersection was only for school use and only for guided school activities.  Most schools are built in residential areas, so a crossing—any crossing—should be useable by everyone in the neighborhood whenever needed. A second problem with the arrangement as presented is that most of the time there is probably no hindrance to normal vehicular traffic speed and flow at this intersection—I’m guessing a speed limit of between 25 to perhaps 45 mph—so drivers are not expecting or planning to slow down and often won’t, even if the yellow lights are flashing.  

There are several types of flashing lights that are designed for use by all pedestrians (and not just during school hours). These include RRFBs (rectangular rapidly flashing beacons), which are activated by a pedestrian wanting to cross and advise oncoming motorists to stop or yield to a pedestrian crossing; and HAWK signals (High-intensity Activated crossWalK), which are actually red signals that require a motorist to stop. To allow pedestrians to activate the existing school crossing signals would probably violate either the MUTCD or other roadway standards. However, it is worth noting that all of these means to highlight crossings should be considered band-aids, and the best approach to promoting safety while crossing the streets is to design streets meant for walking.

This could include narrowed area, trees and other traffic calming measures that would distinguish the area as a place to slow down and be cautious, with or without flashing lights.  If this is, for some reason, not feasible, at least the standard button that starts the signal so that everyone has the opportunity to cross at any time, although I do hate those buttons with a passion. Why isn’t it a people-crossing with buttons for drivers to push when they want to cross the people road?

Comic by Dhiru Thadani. Used with permission.

Comic by Dhiru Thadani. Used with permission.

How would you respond to this question? Jump in with your answers in the comments!

Note: R. Moses is not meant to be professional engineering advice nor should be relied upon as such. Consult your own technical professional before proceeding with your own project.


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