There is a specific rule against bhikkhus owning vehicles.

Obviously, “motor vehicles” were not available in the Buddha’s time and most travel would have been on foot.

However, there was the case:

…when the group-of-six bhikkhus went in a vehicle yoked with cows and bulls, they were criticized by the laypeople.

The Buddha then established a fault of Wrong-doing for a bhikkhu to travel in a vehicle; later illness was exempted from this guideline…

Travelling in a vehicle in the Buddha’s time was an extravagance.

A strict application of this training in Thailand is not allowing bhikkhus to drive or own vehicles, and (officially) not to ride on motorcycles.

Bhikkhus were allowed to use ferry boats, etc. (In Thailand, bhikkhus from riverside monasteries will go on alms round by boat.)

Learn more about the Theravadin Buddhist Monk’s Rules here:

The Bhikkhus’ Rules – Guide for Laypeople