Column: Waiting Too Long for the Go
Looking east, crossing Ashley on the south side of Liberty Street.
The city of Ann Arbor has been installing some new traffic lights around town. Traditional signals display a “Walk” light for as long as 25 seconds. This new type of signal displays a “Walk” light for only four seconds, out of a total cycle of up to 90 seconds. One example of such a signal is the crossing of State Street at Liberty Street downtown.
The cars at these signals get up to a minute of green light. The rationale for the short “Walk” signal is that it includes a staggered timing that allows pedestrians to get into the crosswalk and be more visible to turning motor traffic, thus making their crossing safer. But this staggered timing could also be achieved even while giving pedestrians far more than 4 seconds to start crossing. The extra time would come from the green time for cars. So the four-second “Walk” timing represents a choice to move cars more quickly through the intersection by imposing a waiting penalty on pedestrians.
I became curious as to how much of a penalty this really is. What if we accepted as a matter of course these short “Walk” lights at all of our street crossings? Rather than make many walking trips with a stopwatch, I wrote a simple pedestrian simulator computer program, and sent it on hundreds of simulated walking trips across town on Liberty Street, between the State Theater at State and the Fleetwood Diner at Ashley. This is a distance of 2,500 feet with seven traffic lights.
I used five feet per second as my walking speed. That’s the average for men under 60 in the U.S., according to a Portland State University study, and agrees closely with my own walking speed. At this speed, if there were no cars or signals, it would take a little over 8 minutes to cross town.
Note that the amount of time it takes to cross town depends only on the “Walk” light timing, and not on the flashing “Don’t Walk” timing. Legally and practically, there is no difference between flashing and continuous “Don’t Walk.” Both indicate that the pedestrian should continue crossing if already in the crosswalk, and to stay on the curb if not.
Other than the walking speed, I had to make one important assumption. I assume the timing of the different lights is uncorrelated, that is, the phase of any one light at the time a pedestrian arrives is random. This is in fact not the case. Many of the lights are timed for the benefit of cars, so that someone driving at a constant speed through town will only have to wait for the first light, then will be able to breeze through the rest of them without stopping as each light turns green. I don’t know how this timing affects pedestrians, but since it’s done for the benefit of motor vehicles, I doubt that it helps people on foot.
There are two questions about the new signals I wanted to answer. One is how long it takes to get across town. From a practical point of view this is the question that matters. The other question is how many lights I have to wait for. Waiting for lights is often strictly a nuisance factor, but an important one when considering the walkability of a place. Waiting for lights in the wintertime probably qualifies as more than a nuisance.
Armed with my pedestrian simulator, I made 700 simulated trips across town for each of two scenarios, first with the old, longer “Walk” timing (25 seconds), then with the new (4 seconds). With the old signal timing I made it across town in an average of 10.5 minutes and waited for 4.8 red lights. With the new timings, it took an extra 2 minutes for a total of 12.5 minutes, and I had to wait for 6.6 lights.
This may not seem like a huge penalty. Two minutes isn’t all that long – less time than most of you will take to read this column. What if drivers had to pay a similar penalty? Ann Arbor has recently announced plans to make Fifth and Division streets more pedestrian friendly by adding bumpouts and other calming measures that could delay drivers by up to 20 seconds. This prompted several angry letters to the local newspaper from drivers who felt this was an unreasonable penalty. Yet the new signals impose a pedestrian penalty six times greater.
Looking east, crossing State on the south side of Liberty Street. Two minutes elapsed from the time The Chronicle set up on the corner and the time this photograph was taken – of a group of pedestrians who all failed to notice the "Walk" sign when it was displayed, grew impatient waiting, and finally crossed against the light.
And what about having to wait for an average of 6.6 red lights, on a trip that only has seven lights? This means that on most trips, pedestrians will have to wait at every light. They will go all the way from Ashley to State, a distance of almost half a mile, without encountering a single green light. My guess is that if people on foot have to start waiting up to a minute and and fifteen seconds at each intersection while the cars go right through, they may be tempted to start crossing against the light.
As far as I can tell, these new signals are being deployed without any public notice or hearings. At a time of increased road congestion, high fuel costs, and global warming, I’m not convinced it’s good public policy to sacrifice pedestrian convenience for the benefit of motorists, especially in the downtown area. Changes in public policy deserve public debate.
Note: Jim Rees is a staff research programmer at the University of Michigan.
Jim -
I have downtown pedestrian timing on my mind as well, since there’s some probabilistic modeling involved in getting from wherever I am to the bus stop in enough time to catch the bus without running.
My usual rule of thumb is that it should take about a minute per block, with some allowances for lights.
What I’ve noticed, at least casually, is that walk lights around th downtown differ wildly in their pedestrian friendliness. Liberty St. is never noticably a problem except at Liberty and Thompson, where everyone complains about that crossing (cars, bus drivers and pedestrians alike). State Street, on the other hand, is a complete mess; at State and North U you will be hard pressed to find a pedestrian actually crossing with the light since pedestrians never have any amount of continuous walk light.
The innovation from other cities I’ve seen which addresses this neatly is in Pittsburgh, where some intersections have a cycle where pedestrians have right of way on both sides, and where diagonal crossings are OK during that part of the pedestrian cycle.
This article and the comments so far should be forwarded to City Council. It is the aim of this community to be pedestrian friendly, according to public policy, and it appears that, once again, they have allowed the traffic engineers to go wild. I remember that when the changes to “two way” in the State Street area were made, the engineers said it would “slow traffic down” – well, duh! That was the whole point. Maybe these traffic crossing times were their revenge. In any case, it is the City Council that makes public policy, not the engineers.
I’m a 50+ woman who has multiple sclerosis, so I definitely have speed and gait problems when walking. However “use it or lose it” is definitely true in my case. While I appreciate your efforts to make pedestrian travel more practical, I question your standard of using under 60 males as a criterion. Isn’t it more important to make sure our senior citizens, who may no longer be able to drive, young citizens encumbered with young children, etc., be able to walk safely and with a minimum of discomfort as well?
Mary Ann Baclawski wrote: “Isn’t it more important to make sure our senior citizens, who may no longer be able to drive, young citizens encumbered with young children, etc., be able to walk safely and with a minimum of discomfort as well?”
I think the choice that Jim Rees made in selecting five feet per second (average for males younger than 60) as a walking speed for his computer simulation, was guided mostly by a need to pick some walking speed or other for the model, to get an idea of the waiting penalty. That is, I don’t think he’s arguing for optimization of the signal timings across town to increase the chances of a 5-foot-per-second pedestrian of encountering a “Walk” signal with no waiting.
I think Rees is arguing simply for longer “Walk” signals — which would benefit all pedestrians, including senior citizens and those who are accompanying children.
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Because my talents lie in walking and recording times more so than computer programming, I took a couple of actual walks across town along the route Rees simulated with his program. Here’s what I got:
Ashley to State along north side of Liberty
1:01 Ashley to Main
0:33 Wait at Main
1:01 Main to Fourth
0:12 Wait at Fourth
1:02 Fourth to Fifth
0:42 Wait at Fifth
1:44 Fifth to Division
0:00 Wait at Division
2:45 Division to State
1:08 Wait at State
0:05 crossing State
Total 10:19
Return Trip along south side of Liberty
2:06 State to Thompson
0:12 Wait at Thompson
0:43 Thompson to Division
0:39 Wait at Division
1:44 Division to Fifth
0:00 Wait at Fifth
1:01 Fifth to Fourth
0:47 Wait at Fourth
1:03 Fourth to Main
0:23 Wait at Main
1:01 Main to Ashley
0:04 Wait at Ashley
0:05 crossing Ashley
Total 9:53
When I am crossing streets downtown or anywhere with a stoplight, I wait in my stodgy way for the walk light. However, I often see people walk across against the light. Usually they have made a good decision based on the lack of any traffic coming. Sometimes, though, they are simply trying to beat the traffic. This has the potential of causing an accident or of requiring traffic to slow down so as not to hit the pedestrians.
If we bias walk lights against pedestrians, I believe that we will see more and more of this running against the light. If it appears that lights are unfair or prejudicial to pedestrians, more people will try to circumvent them. This is not a good outcome for anyone.
Bad laws make scofflaws.
This short pedestrian-crossing time is something I have been complaining about since the “pedestrian” upgrades were made on State Street. Not only did they make the streets two-way, but they created the crazy 3-second walk sign (I’ve always counted three seconds on the State Street and William crossing, but maybe it is four). The combination made it so much harder for pedestrians to navigate in that area. It is especially discouraging because these changes were billed as pedestrian enhancements. I’m not sure if the traffic engineers ever walk anywhere, but none of the pedestrians I know who use those intersections daily thought the changes were upgrades! It seems like if you just state that traffic changes are pedestrian enhancements, people who don’t walk believe you, even though they are actually traffic upgrades and not pedestrian-oriented at all. It used to be that pedestrians waited more for the lights on State, but now everyone just goes when they can because the light so rarely is with the pedestrian.
My favorite is the crossing at Packard on the east side of Main St. Hit the button to indicate your desire to cross and the signal switches to “Walk” immediately in many circumstances. The challenge is to cover the ten feet between the pole the button is on and the crosswalk before the signal changes to a flashing “Don’t Walk”. I can almost do it if I’m in full stride and just hit the button as I pass. Poor “stodgy” Vivienne might never get across.
Proposal: minimum 6-second “Walk” signal. That’s 50%-100% longer than the current minimum. (Like Julie’s assessment of the crossing at State, I think the one at Packard is only 3 seconds.) That should be sufficient for the vast majority of pedestrians to (notice the change–see Dave’s caption to the second photo–and) at least enter the crosswalk before the signal changes. Please note that I’m suggesting this as a quick, reasonable fix for a specific problem, not as part of a larger improvement to the system.
First just a quick word of thanks to traffic engineer, Les Sipowski, who works for the city of Ann Arbor, who took the time to confirm for us much of the factual basis for Rees’ piece, as well as to explain the various kinds of traffic signals, which are documented in a previous Chronicle piece with a headline something like “Time for Transportation.”
Second, I think the the intersection of State and Liberty has a history of unsatisfactory solutions for traffic and pedestrian flow, and this one continues the tradition. Here’s my question: why does anybody need to drive on Liberty Street between Division and State? I mean, if you’re on State headed either direction, and you decide to turn west on Liberty, why couldn’t you get to where you’re going by turning on Washington or William? And if you’re on Liberty headed east waiting for the light at State, then you must have come from somewhere west of there that would have let you get to where you’re going more efficiently than to head into the mess that is that T-intersection.
Even thought it’s Main Street that people typcally talk whimsically about turning into a pedestrian mall, I think Liberty between Maynard and State is a better candidate.
Great article Jim.
You wrote…
“Legally and practically, there is no difference between flashing and continuous “Don’t Walk.” Both indicate that the pedestrian should continue crossing if already in the crosswalk, and to stay on the curb if not.”
I’m not questioning the method of your experiment, but just want to make the tangential point that sometimes a countdown timer tells me there is more than adequate time to cross even though it is blinking DON’T WALK and I haven’t stepped into the street yet. The countdown timers are very useful in this regard, especially since the WALK signals are so darn short and the continuous DON’T WALK signals are so darn long.
Not all crossing situations in town bug me, but trying to cross State at William a couple of times a day like I do is bothersome. As others have mentioned, State and North University, and State and Liberty are particularly problematic in my mind.
A related concern I have is that buses cross William going north on State very fast and close to the pedestrians waiting on the curb to cross. It doesn’t leave much room for error.
I want to thank all of you for your thoughtful comments. I sometimes feel like I’m tilting at windmills when I complain about this, so it’s good to know others have noticed this problem too.
Ed – I used to like State and North U, because there was no light so I never had to wait for it.
Leah – I wrote to my council members but got no response. Policy should be set by Council, not by traffic engineers, so it would be nice to engage them on this issue.
Mary Ann – I used 5 fps because that’s how fast I walk. Guidelines range from 2.5 fps by the Institute for Transportation Engineers for “areas with high senior concentrations” to 4 fps by the Manual on Uniform Traffic Control Devices. These are intended to be lower limits used to set the minimum walk times for signals. But no matter how fast you walk, you will get a two minute delay and have to wait at every light if all downtown signals are changed to four second timing.
Dave is right, I’m arguing for longer walk lights, and that will benefit all of us no matter how fast we walk.
Vivienne – It would be interesting to spend ten minutes or so at a four second light and at a 25 second light to see which has the better pedestrian walk light compliance. I’m pretty sure the four second light encourages illegal and dangerous behavior. I’d like to see the same logic applied to pedestrian light timing as is applied to setting vehicle speed limits. That is, lengthen the walk light timing until 85% of pedestrians are in compliance. (I’m just kidding here, I think it’s a terrible idea to “solve” the speeding problem by legalizing reckless driving).
Julie – I couldn’t agree more.
Steve – I hadn’t thought of that. At the ITE 2.5 fps speed it would take 4 seconds just to get from the pole to the curb, longer really because you need some time to start up. There is no way you’re going to make it. I’ve had the same problem at the southwest corner of Plymouth and Green.
John – The countdown timers bother me. They seem to be intended to encourage pedestrians to break the law by starting to cross during the flashing don’t-walk. They also have an element of “hurry up and get out of the way” to them, when pedestrians are legally entitled to take as much time as they need to cross.
One thing that really bugs me about the crosswalks at North University and South State is that the cross-time is VERY short, for such a well-traveled area. On top of that — drivers feel that they must turn right on red, and I have seen several instances of drivers almost hitting people who were crossing properly. I think that at that intersection there should be NO RIGHT ON RED from 8 am to 6 pm.
I was amazed to read an article attached to my utility bill from the City of Ann Arbor ( water matters fall 2008 vol. 7 no.1) titled PEDESTRIANS RULE ! I suggest that who ever wrote this try crossing any of our downtown intersections during weekly rush hour traffic, The no-look, cell phone, stressed out, parking spot hunter considers you fair game, after a decade of living in down town I have witnessed a number of pedestrians being hit by cars and advise anyone to never assume the driver of that car coming at you has read the insert in his water bill.