> Someone moving at 100km/h through a city isn't any less likely to kill someone when hit just because they are poor.

Actually we could argue that it's more likely due to the poor average condition and old age of their cars. A new Mercedes brakes much better than a 20 year old Skoda and usually has auto-braking systems and braking force enhancers.

However "going through a city" is very general. There are several actual highways (by law as well as by construction standards) in Prague going through the city where the speed limit (70 km/h) is frequently broken with no possible victims - the exact same road has 130 km/h limit outside the city.