Would it make sense to automatically require cars to obey to speed limits?

Given that:

- speeding causes many fatal accidents, especially in built-up areas - GPS is cheap - we have detailed information of speed limits in built-up areas - self-driving cars likely obey these speed limits - lower speeds produce less emissions

Why not implement a hard requirement that cars simply cannot exceed local speed limits in built-up areas (and school zones)?

If anything, in exchange for a discount in insurance premium, but as time moves on, simply make this a requirement for new cars.

I see this as very low-hanging fruit to implement, and leverage existing technology that is already available to everyone.