-Striking a pedestrian on a limited access highway where they are not allowed will usually result in both parties being held responsible.
I don't think this is a solid rule across the country.
I'm familiar with incidents in my locale where a pedestrian has attempted to cross a "limited access highway where they are not allowed", been struck and killed, and the driver not faulted (unless he/she fled the scene, which is a different crime entirely).
I can think of one recent incident where a panhandler was struck in the middle of an intersection by a vehicle that had the right-of-way as the panhandler was walking back to the curb after collection a "donation" from a vehicle that had previously stopped. The panhandler walked across a turn lane, which was green, at night with dark clothing, and the only fault credited to the driver was that he/she fled the scene.
I can think of another incident several months ago involving a divided highway, not pedestrian accessible, and construction on an overpass above it that made it temporarily inaccessible for pedestrian traffic, and a minor who defied all of the signage to attempt to cross the highway on foot. She was struck, killed, the driver stopped as required, and no fault was attributed to the driver.
Seriousy, if someone pops out of the dark and winds up directly in the path of your 65mph car it cannot reasonably be the driver's fault. We don't blame trains for killing someone who hangs out on the tracks, against all warnings and common sense.
As I'm fond of telling my own kids, there are laws of the land and laws of nature and laws of physics. The laws of physics trump them all. You can violate the laws of the land and do things that are crimes against nature without violating the laws of physics, or you can be perfectly legal and in harmony with nature but an F150 still trumps a bamboo bicycle every day of the week.
I've noticed several design suggestions in your code.