Speed limits¶

Mark O'Brien has a valid comment about using cell phones while driving, which don't seem to be the hazard they are. The Dutch info I heard on this was that there was no difference in handfree/not-handsfree usage, that they were each as distracting. But apparently both not so distracting as other causes.

He's from Australia and says: it's like the laws here which dropped the speed limit in residential areas down to 50km/h. the minister was praising these laws in recent news for having dropped the fatality rates in those zones. my suggestion... drop the speed limit to zero and you won't have any accidents at all... doh!

That send me a bit up the wall. That reasoning was a bit sensationalistic, imho. I'll explain below. I was a bit surprised at his remark about the 50km/h limit. He apparently doubted if it had any effect and joked about a 0km/h limit.

In the same way, I could joke the other way. If speed doesn't make a difference, just allow everybody to drive 120km/h in residential areas as that won't make a difference in fatalities. Doh.

In the Netherlands, 50 is normal in residential areas, except for the larger, completely free roads where you can do 70. The REALLY residential areas are often 30. But, the Netherlands is a teensly little bit more crowded than Australia, which shows in our town planning.

This might mean that 50km/h really is idiotic in Australia, I don't know. But speed does have a large influence on fatalities. Just multiply an average 0.6 seconds reaction time by the speed in meters/second. With 50 km/h that's 8.3m, with 70 it's 11.6; that is already the difference of somebody standing in front of your car and somebody lying under your rear axle. And I didn't yet include the braking time, which takes an quadratic amount of time extra with extra speed (kinetic energy = mass * speed^2).

The article he quotes doesn't include speeding: that was apparently not the sort of cause they looked at. What can we say, then, about the effect of speed? Well, lower speeds by definition give you more margin of error. So, when making the error (rubbernecking, distracting kids in the back, etc), they could have had more time to correct before things went boom.

A big reason for not liking speed limits is the difference between what the road looks like and what the speed limit sign says. In the Netherlands, the traffic safety organisation strongly advocates making the road's maximum speed visible. Don't put a 50-limit on a 2x2lanes, split lanes big urban road: that looks like at least 70. In many places, they're fixing up the roads to make them more "logical".

Something else: he had a nice link about always leaving your computer on