30KPH car-pedestrian collisions are >> 95% survivable. The fatality rate drops dramatically above that speed. Dropping speed limits to 30Kph in areas with shared infrastructure and strictly enforcing them can drop pedestrian fatality rates all the way to zero:
https://en.wikipedia.org/wiki/Skyway EX: https://en.wikipedia.org/wiki/%2B15
Alternatively, you one or both can go underground. (https://en.wikipedia.org/wiki/Underground_city#United_States) Crystal City VA for example has a huge underground mall that almost completely removes pedestrian tragic outside and connects to the subway system. Sadly, it's not a strait path, but there are ~50 buildings connected and it becomes really useful if you live and or work in the area. (http://www.thecrystalcityshops.com/_files/docs/cc-shops-2014...)
Not a given. At speed, cars handle more securely than bicycles; cars have power brakes, ABS, traction control; modern cars often have automatic collision avoidance systems.