Tuesday, 22 March 2016

Sustainable Safety: A thorough look into each of the 5 principles. Part 4: Forgiveness


That news article inspired me to write this blog post so soon. It made me want to state that accidents on the roads are in fact mostly accidents, nobody wanted to commit the road crash. Very few times is anyone ever trying to cause a crash, and of those who do, often times it's for things like insurance fraud or something like hat.

However, the big difference is acknowledging that we make mistakes, frequently, regardless of what mode of travel we use, pretty much involuntarily, and that we design our roads and as much as possible, the vehicles we use, to account for those mistakes, and make them less dangerous, and not lethal, as the crash last weekend shows how bad a mistake can be.

The Dutch call this principle "forgiveness", well, obviously they would normally use the Dutch word for it, vergiffenis, and it's made a huge reduction in the number of crashes, injuries and fatalities on their roads on roads which have been redesigned or originally built to the Sustainable Safety standards.

As much as I and many others would want people to be always able to make the right choices on the roads, cycleways and walkways, if we can walk into lamposts or stub toes by accident, what hope do we have that driving a car at something like 50 km/h being incapable of error? It's a given that unfortunately we don't have the ability to remove.

Let's see what can be done to make our roads forgiving of errors and not relying on perfect behavior, and when crashes do happen, making them as non lethal non injurious as possible.

You'd be surprised how often cars manage to veer off the road and while in some cases you're lucky and all you'll encounter is grass, in a lot of cases you will hit something like a pole or tree, or other cars. This often happens on main interregional through roads, designed like motorways or divided highway. This is because then driving becomes boring, and especially here we design them to be quite straight and with little in the way of scenery. That makes a direct line, but it makes highway hypnosis a real danger, one that kills thousands each year in the US. It makes you nod off, or go to autopilot, that is pretty much only capable of holding the streering wheel in roughly a straight line and hold the gas pedal down. The other part of your mind is in la la land, dreaming about something else.

This can be less of a danger by using tactile feedback between lanes and especially on the shoulders, rumble strips have saved a lot of lives, by creating clear zones, wide shoulders on autowegen and motorways with a stabilized non paved shoulder, and if the thing that you might crash into is more dangerous than hitting a guardrail, then installing a guardrail. Extra campaigns to take breaks at regular intervals, and rest stops to take those breaks safely, as opposed to stopping on the shoulder for example, at regular intervals, around every 50 km, couldn't hurt either. However I should make it clear that these extra wide clear zones greatly increase speed and lower's drivers attention on the roads that don't need to be high speed roads, like on the 50 km/h urban arterial roads and especially the low speed low volume access roads.

Cyclists hit the curb more often than you might think. Having a splay curb, angled at between 30 and 45 degrees, or more preferably, having a flat curb (this would be used when the asphalt of the cycle path needs to be contained), and having wide clear zones as well, preferably grass and soil ones rather than concrete and metal ones, helps as well. The curbs must be low, between 5 and 7.5 cm for an angled curb, and there must never be an upstand, always flush. Even a few millimetres can grab a tire and through you off.

Intersection design as well can really help contribute. When you provide wide areas between the things you need to do, it also simultaneously increases reaction times. When you have as few things as possible that a road user is capable of doing, you have less ambiguity about what they will do next, and if it becomes apparent that they are making a mistake, you have a lot more room to slow or stop or maneuver to avoid the problem if need be. Roundabouts are perfect for this, provided you have the non annular cycle path design, as they give you very long reaction times, they give you very good angles, and they make doing things like driving too fast around a roundabout much harder to do, especially by accident. And if a mistake does happen, the speeds are low enough that you can react to those mistakes, and if the worst happens and a crash does happen, the speed and angles make crashes far less dangerous than the often 50 and 60 km.h, often with traffic going 60-75 km on many arterial roads, speeds we use at other arterial to arterial intersections.

The very existence of cycle paths makes it much less likely that any mistake that a driver does is going to affect cyclists due to the space and physical protection between them. Many drivers veer over a painted line, but it is much harder to veer over a curb.

Vehicles themselves can become better. We have far safer cars than we did back in the 1950s, when if you were crashing into something with a 1 tonne car you would have about the energy of a stegosaurus dropped from a three story building, but we could do better. We could slightly increase the length of the crumble zone, perhaps up to 75 cm, which could be possibly done by shrinking the engine by adopting electric vehicles that need less engine space. We can add skirt guards around the bottom of large trucks, the kind with the space underneath the box part, so that if a truck does drag someone underneath the results should be less dangerous, though certainly not desirable. And we could potentially mandate that each motor vehicle shall have a collision avoidance system, at least on freeways and main roads where highway hypnosis is likely. These things already exist, and Mercedes recently got some government to close off a motorway for a little bit to test out their automatic truck. It had a human driver ready to step in if needed, but it does show that at least for the environments we have on the long distance roads, it shows considerable promise to be feasible very soon.

We have a lot of ways to improve our roads, but the tragedy of that pedestrian killed, all people killed or injured in crashes, is almost always avoidable if we had roads that forgave error and met the other principles of Sustainable Safety. We cannot ignore the elephant, or rather the car, in the room any longer. How much longer until we realize that the Dutch have figured out the way, and that it can be exported anywhere that is willing to receive it? Many people, myself included, and many professionals at universities and roadway design engineers, people who devote their lives to this, often know this. Humans are fallible, and few people will openly admit that they themselves are. It's natural to think this way, but we can control that bias. If you want to go and oppose this, go to the nearest hospital and look around for the nearest victim of of a serious road crash. See whether you can still tolerate your principles making this crash far more likely.

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