Pushing the physical speed limitations of cars is not what kills cyclists and pedestrians. In many countries, those groups are excluded from high speed roads.

These deaths predominantly happen around 30mph, at junctions and other road furniture.

Edit: I've based that on UK experience, while TFA puts most US accidents on "arterial" roads, which can be 30-50mph. This doesn't change what I'm saying to you though, cyclists aren't dying because cars explode at 50mph.