>a-french-anon

20 miles per hour is 32km/h, 2 above the french residential limit of 30km/h

You can't enforce a speed limit by simply placing a speed sign and hoping everyone is going to magically follow them. More cops or speed cameras isn't going to work either.

My city is currently working on a plan to lower the speed limit from 50kmh to 30kmh (30 mph to 18 mph). The entire thing is a multi-year program because it essentially means redesigning those roads from scratch.

A road which has been designed for its speed limit doesn't even need a speed sign - the driver will naturally be driving at that speed already because anything faster will feel unsafe to the driver.

It's not flawless but sticking up signs has a reasonable effect. I'd say at least 50% of the people who drive on the local 20mph roads near me abide by the speed limit (that has not active enforcement) and this prevents quite a few others from speeding.

(I agree on the road design point though...)

That's just wishful thinking. You probably wished they didn't so you could make that point, but they 100% work :)

They have the benefit of not slowing down emergency vehicles too!

I don't know why you think anti-car people would raise pitchforks at that. In fact this was my criticism of the proposal when I lived in Wales; there seemed to be little attempt to alter the street environments to match the lower limits. I want effective 20 mph zones and that can't happen just by changing a few speed limit signs.

My prediction was that it would backfire: motorists behaviours wouldn't change, so the speed limits would be flouted even more than they are now. Councils wouldn't enforce it consistently, giving credence to the view that it's simply a revenue-generating scheme and/or a way for police to punish people arbitrarily. This is already the case for parking offenses; Cardiff motorists can park on double-yellows with almost complete impunity. Then, populist backlash, law gets repealed, making it even harder to get support for real street safety measures in the future.

If you look at the data for speed limits vs deaths they show pretty convincingly that what drivers think are "completely normal speeds" are actually "reckless driving".