Context is 20 mph steets, making them more complicated and narrower forces drivers to slow down to not hit anything. Straight and wide streets allow drivers to speed as they feel comfortable.
Motorways on the other hand encourage to speed with wide lines, long view distance, long turn radiuses, hard shoulder and long paint stips
A center line with floppy cone-pole things, barriers on the side (such as planters)(bonus it keeps pedestrians and cyclists safer and beautifies the area)
it's enforced by road design, and in some cases our desire to not murder children with our cars. call me autistic (I am) but I follow speed limits in residential areas even if the road is designed like a formula 1 track
Well, that is a lot of money (for me and presumably you), but without proportional (to assets) fining it makes laws pay per use. In otherwords, money is not a good judge of character; people can have disposable income and ignore the same fine that changed your mind about speeding. And as another commentor said, preventing is better than punishment.