“The problem is that speed limits have for a long time been artificially low to adjust for the complete lack of enforcement, combined with the optionality this gives to police. It is often actively unsafe to drive the speed limit. What we should do, obviously, is not to stop requiring license plates or not enforce the law. We should enforce the law, and adjust the law for the expectation that it will be enforced.”
I don’t know if it is the same in the USA, but in the UK (where speed cameras are, I think, much more widespread) their is a widely held perception that you can exceed the speed limit by 10% and be guaranteed that nothing will come of it. However, I have noticed that Satellite navigation systems consistently indicate the cars speed is 10% slower than the speed displayed on the car’s speedometer. Having brought this up in conversation it seems like everyone who has checked (with different cars and sat navs) finds the same thing.
My theory is that a car manufacturer is more likely to be in legal hot water if the speedometer under-estimates the car’s speed than over-estimates. So they have all clustered around a 10% exaggeration. Which in turn leads to the myth that “speed cameras only go off between 75 and 80mph, even though the limit is 70mph”.
A final data point, going through average speed checks (a computer-camera reads your number plate at the beginning of the road, starts a clock which stops when another camera reads your plate at the end of the road) all the lorries appear to be going a little over the limit (the magic 10% again). If you drive a lorry you probably know if your speedometer is lying, and maybe your employer gives you one that is actually accurate.
So adjusting and enforcing the adjusted values makes sense. I am just speculating their is an extra 10% discrepancy in the speeds people think they are doing and what they are actually doing.
“The problem is that speed limits have for a long time been artificially low to adjust for the complete lack of enforcement, combined with the optionality this gives to police. It is often actively unsafe to drive the speed limit. What we should do, obviously, is not to stop requiring license plates or not enforce the law. We should enforce the law, and adjust the law for the expectation that it will be enforced.”
I don’t know if it is the same in the USA, but in the UK (where speed cameras are, I think, much more widespread) their is a widely held perception that you can exceed the speed limit by 10% and be guaranteed that nothing will come of it. However, I have noticed that Satellite navigation systems consistently indicate the cars speed is 10% slower than the speed displayed on the car’s speedometer. Having brought this up in conversation it seems like everyone who has checked (with different cars and sat navs) finds the same thing.
My theory is that a car manufacturer is more likely to be in legal hot water if the speedometer under-estimates the car’s speed than over-estimates. So they have all clustered around a 10% exaggeration. Which in turn leads to the myth that “speed cameras only go off between 75 and 80mph, even though the limit is 70mph”.
A final data point, going through average speed checks (a computer-camera reads your number plate at the beginning of the road, starts a clock which stops when another camera reads your plate at the end of the road) all the lorries appear to be going a little over the limit (the magic 10% again). If you drive a lorry you probably know if your speedometer is lying, and maybe your employer gives you one that is actually accurate.
So adjusting and enforcing the adjusted values makes sense. I am just speculating their is an extra 10% discrepancy in the speeds people think they are doing and what they are actually doing.