I believe EU regulations lead the way here. Basically, part of crash testing now involves impacts with pedestrians. My understanding is that the primary effect is on the front-end shape of vehicles. When striking a pedestrian, you want them to roll up onto the hood, into the windshield, to spread out the impact as much as possible (in area and time). More recently, systems like automated emergency braking have helped too.

Here, this wikipedia page gives an overview: https://en.wikipedia.org/wiki/Pedestrian_safety_through_vehi...