Not sure where you are getting this information. Where there are trains, people take the trains far more.
In Tokyo, the vast majority of passengers rely on the extensive and efficient train system, which is often considered the best in the world. Cars are less commonly used due to high parking costs, traffic congestion, and the convenience of public transportation options like trains and subways.
Transportation Options in Tokyo
Train Passengers
Rail Network: Tokyo has the most extensive urban railway network in the world, with 40 million passengers daily.
Frequency: Trains run every two to three minutes during rush hours, ensuring minimal wait times.
Accessibility: Major stations are equipped with elevators and clear signage in multiple languages, making it easy for tourists to navigate.
Car Usage
Driving Conditions: Driving in Tokyo can be challenging due to narrow roads, heavy traffic, and limited parking availability.
Parking Costs: Finding parking can be difficult and expensive, with many areas lacking sufficient parking lots.
Rental Considerations: Renting a car may incur additional costs such as tolls and drop-off fees, especially if returning the car to a different location.*
https://en.wikipedia.org/wiki/Transport_in_Greater_Tokyo