Broadside, it all depends on were you are and what city or rural area. In South Florida it will be 3 to 4 hours maybe a little longer in small places but no more since there are many people that live 10 to 30 miles from there home so when they see that every car and bus is not working and they can’t walk home that easy then there will be trouble ever were and no police to take care of the problem.
Any cars or trucks that are from 1975 on down will work but how are you going to go though streets that are full of cars and trucks that do not work and the sidewalks are full of people. If you use your 1970’s car or truck you may get shoot at or killed pretty fast. Walk home and get the kids. Walk to there school.