When my RSI/TOS was at it's worst {spasms and muscle tightness}
it was really uncomfortable to ride in the car. Still bothers me sometimes if it's been a long day or a long ride...
Potholes , railroad tracks, stopping, even rough shifting really put an extra strain on my neck.

If it's your or family car, getting touring tires and softer shocks will help some.
Some cars just have a smoother/softer ride than others too.
So if you have a choice of vehicles - pick the one with the soft ride.

Otherwise - extra pillows, a neck roll or rolled towel, maybe even a padded seat cushion to help absorb some of those bumps...