Here in the UK the train to London is five hours and £75. The coach is £15 and eight hours. Four people in a car perhaps £10 a head. Trains are nicer but there is something annoyingly mysterious about the ecomomcs of it all.
But a car costs a couple pounds every day for registration, insurance, regular maintenance, new parts (tires etc). If you go to London and spend 10 days there, this is easily 50-100 pounds even if it's just parked and doing nothing. Now also add possible parking costs and emergency costs for maintenance if the car breaks down -- a friend of mine went with his car to the seaside with kids a couple years ago, and the car broke down midway. It cost him 2.5k for his local shop to pick it up and repair. The shop on the spot even gave him a 4k quote.
And of course you have the upfront investment for the actual car which is a few thousand for a used car or at least 15 thousand for a new car these days.
EDIT: There is also an inherent feature in trains that greatly reduces the rate of progress. With toad vehicles there is very good decoupling between the track and the vehicle, from a design pov. With trains the chassis design is more coupled to the track design. And since you can’t really upgrade track easily, on both train and road, there are more constraints in new train design.