Friday, 26 February 2016

Efficient traffic lights for cyclists and pedestrians

Many people don't like traffic lights. I am among them. However they are someone required to have safe crossings. It is preferable to avoid them if you can, a roundabout with not too much volume on your arm means that even while yielding to the cars still isn't too bad, and you can often have non stop journeys anyway. An underpass and sometimes overpass can also be used in some places. And having your route to avoid the main routes for motor traffic means that very often you can avoid traffic lights, and in many cases even roundabouts. And cycling away from motor traffic is more pleasant anyway. But at some point in Edmonton and almost everywhere else there is at least some place where there simply must be a traffic light in your path. Let's see how to make them as efficient, convenient and safe as possible.

First, let's make the lights themselves easier to use. I propose that the lights be on the nearside. But in order to see the traffic lights when you are first in the queue means that the stopping line either must be set back, or eye level lights must be used. I prefer the latter as more stacking room exists for other cyclists. The lights can have a countdown timer on them, to let you know how short the wait will be. Inductive loops in the surface makes it so that you don't have to press a button, but even there, there will be a backup button just in case the loop doesn't detect you. The waiting time indicator should begin counting down to let you know that you have been detected. Having a set of inductive loops as far away from the crossing as possible so that once no other path can be chosen by bicycle, it will know that you intend to cross, and will thus inform the traffic controller that you wish to cross.

But of course if the light cycles are too long, the waiting times are insensible or otherwise they are too inconvenient, people won't care if there is a button to press or not. So getting the waiting times right is essential.

First, have detection for the motor traffic as well. This means that if no motor traffic is detected, then why would there be a need of waiting for traffic that doesn't exist? Already this greatly improves the light sequencing. Most lights in Edmonton have a fixed time basis, meaning that once programmed the light cycles cannot be changed. This is just dumb. Also, we should have separate signals and separate detection systems for the different directions of motor traffic. Maybe I am coming from a side road and want to go straight on, but from my left there is traffic that is going to make a left turn. If that is the only traffic that wants to cross, and neither would be crossing each other's paths, why not let them go at the same time?

Next, when possible, make it so that all of the movements that you could want to do on a bicycle that don't cross the paths of motor traffic aren't controlled by traffic lights. Many right turns don't cross motor traffic, so no need to wait. Same with T intersections. Same with signalized pedestrian crossings. There is only a need of controlling interactions between motor traffic and other types of traffic when other control options fail, so there is no need of signalizing a conflict between cycle and pedestrian.

Thirdly, let's use simultaneous green for most crossroad intersections, probably with the exception of where in the suburbs major arterial roads cross, and the design of the paths makes it so that there is no need of cycling on both sides of the roads. This makes it much easier to have a left turn, it can be done in one go, and even for straight through cyclists, it is more pleasant to be cycling when motor traffic isn't going, and having separate light phases is safer when well designed.

For crossings that do not involve all arms of the intersection needing to be crossed by cyclists, then often having a default green to cyclists makes it more convenient to them. Motor traffic itself must trigger their own green. More efficient that way.

For intersections that do not have default to green for cyclists, then the lights should all default to don't move or red. This makes it so that you don't need to worry about the amber light runners, and you don't need the amber or red light clearance interval at all if the lights for everyone are red when you arrive but nobody else has just before you. The green light can be given to you immediately.

Crossings should be on the desire lines as much as possible. For some reason the city of Edmonton often doesn't do this at LRT crossings. Why are pedestrian crossings often in need of going 3/4 of the way around rather than a direct path for paths coming from side roads? And this applies more generally. I can't figure out why, but Edmonton consistently makes the wheelchair ramps angled at around 45 degrees so that it almost feels like a scramble crossing for pedestrians except there is never a desire of having that in most places around the city. Why not have them parallel with the routes, rather than a funny 45 degree angle?

And finally, retime the signal programming. It's less tempting to want to cross on red if you know that you have 2 20 second green lights rather than 1 40 second green. I know it involves more yellow lights, but we must take actual behavior into account. We can also give cyclists twice as much green light time as motorists with simultaneous green, or actually whenever cyclists and motor vehicles both have their own independent traffic signals.


We have many ways of making traffic lights more convenient. Why do we so often fail to make cycle and pedestrian journeys just as efficient and safe as motor vehicle journeys?

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