The Problem With Fixed Signal Timings

By Jacklee. (Own work.) [CC-BY-SA-3.0 (], via Wikimedia Commons

On Saturday, my wife and I, along with a friend, headed for the Downtown Farmers Market, and since my wife is less than mobile right now, the result of foot surgery a couple of weeks ago, we opted to drive. Living just outside of what most consider to be downtown in Rossdale we usually prefer to walk but that just wasn’t an option on this day, not unless I wanted to carry Emily up the hill, and the be totally honest that didn’t much interest me. Because we happened to be driving and not walking as we normally would I noticed how little sense the traffic signals in and around downtown make on the weekend.

On the trip to the market and again on the way back we stopped at a red light at the intersection of 99 Street and 101A Avenue. Even if I ignore for a minute that 99 Street is ridiculously overbuilt in this area with two travel lanes for north and south bound traffic plus on-street parking in both directions I really can’t get my head around why the signals would be on a fixed timing pattern when there is next to no traffic on either street. The purpose of a traffic signal is assign right-of-way to vehicles and pedestrians. When used properly they promote orderly traffic movement and to prevent excessive delays. In this case though the signals are the only thing delaying traffic. And that’s a problem; one that, luckily, can be easily fixed.

Most of our transportation infrastructure is designed to handle large traffic volumes for a few hours a day, five times a week. In Edmonton the peak hours account for, if we’re being generous, 20 hours a week, obviously that’s a small percentage of the week. The problem is that if everything is designed for the few peak hours, the transportation system may be inefficient for the remainder of the day. If four lanes are required to accommodate the morning and afternoon rush hour traffic volumes there isn’t much we can do about that the rest of the time, but if a signal needs to be timed in a certain way during the peaks, well that is something we can adjust for other times of the day.

Ideally the city would have a network of traffic signals with different timing plans for the morning rush hour, mid-day, the afternoon rush, and evenings and weekends. Each signal would also include detection (I prefer camera) that would allow for additional green time to be added to the phases that need it when traffic volumes are at their highest, or trigger a green phase when no other cars are present at the intersection. This would provide the city with a traffic signal network that would be as efficient as we could hope for. Those early mornings when you get stuck sitting at a red light for 40 seconds, while no other cars drive through the intersection, would be a thing of the past.

So why don’t we have that system? Cost.

Like most other cities, Edmonton has a large number of signals that can’t accommodate what I described above. Look at the phone in your pocket and compare it to the computer you had 15 or 20 years ago, traffic signal technology has changed in much the same way. Everything has gotten smaller. So we can do more know, but we’ll always be limited by older technology until it gets replaced. We could start replacing everything tomorrow (I know a consultant who would be happy to help) but the realities of budgets likely make that a nonstarter.

This doesn’t mean we should give up though. We can all agree that a one-size-fits-all approach to traffic signals doesn’t make sense. It unnecessarily delays drivers and I suspect (I know that I do it) it encourages jaywalking as well since pedestrians know that there are no vehicles in the area. So what’s the answer? Well, if the purpose of a traffic signal is assign right-of-way to vehicles and pedestrians then you need to ask, what would happen if the signal wasn’t there? Would the intersection be able to operate under a two-way or four-way stop condition?

If the answer to this is yes, then the signal should default to flash mode during periods when traffic volumes are lower – yellow/red or red/red depending on traffic volumes and road types. In the downtown core this would be, at a minimum, from 7:00PM – 7:00AM during the week and all day during the weekends, for all but the busiest arterial roads; roads like Jasper Avenue, 109 Street, and 104 Avenue. Everything else could be in flash mode. The result would be that more vehicles might have to slow down or even stop, but the time spent waiting for the signal to change would be reduced. A simple solution that’ll keep everyone moving, seems like a win-win to me.

3 thoughts on “The Problem With Fixed Signal Timings

  1. DuncanKinney

    Why not just have flashing reds/flashing ambers during non-peak hours for these signalized intersections that are doing more harm than good.

    1. ryanbatty

      As opposed to just at night and on the the weekends, there isn’t really a good reason. Traffic signals are still seen by a lot of people as a safety improvement though, so I would imagine that kind of change would get more push back from the public than changing evenings and weekends would.

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