Thise priorities are things drivers care about.

You get people doing 40-50 in a 25 when the road is as wide and straight as a 40-50 mph but the speed limit has been reduced because there are homes with kids nearby.

Make the road narrow, add curves to it, and suddenly people will do lower speeds naturally because they don't feel like they have as much of a buffer.

Same reason you're more likely to find someone speeding on a highway than down a narrow side street