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Why does everyone drive 10-15 miles above the speed limit?
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Why don’t we raise the speed limit if that’s how fast everyone wants to go?
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Why is traffic enforcement given to very expensive and ineffective police instead of cheaper and more automated traffic cameras?
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Why do we refuse to ever use ANY traffic calming measures? Yes, than you flashing digital sign for telling me I’m going 10 miles above the limit on this incredibly wide and straight and flat road with high curbs and perfect visibility.
It’s a serious confusion I have about how society is supposed to operate because it seems like a complete and total breakdown of logic and sense.
And, yes, I know there’s some thing people did long ago to set the speed limit at some percentile of what people were already traveling at, but that’s obviously a stupid way to do it and we did it anyway. So why?


In most places in the United States speeding is a criminal offense. Each element of the crime must be proven beyond a reasonable doubt. And the accused has the right to confront the witnesses against him in court.
The biggest thing they contribute is proof of identity. When they pull you over and run your license, they can testify with pretty strong credibility that it was you driving the car.
To prove speeding you have to prove that the car was going too fast and that someone in particular was driving.
Having a cop signing the ticket also gives the government a convenient witness who can be subpoenaed to come to court and to testify with personal knowledge of the incident. That satisfies the confrontation clause. Whereas in jurisdictions that have tried pure camera enforcement, the only witness they can usually bring is a low level camera company representative who has no personal knowledge. This leads defendants to demand a lot of discovery into the automated processes of the camera system, because that is what is really accusing them.
Conclusion: US jurisdictions do a lot better with camera enforcement when they create civil infraction liability under state law. But then some forms of enforcement, like license points, may be taken off the table.