Diesel fuel will burn, but is much more difficult to ignite. Buses and coaches have been diesel powered since the Thirties, and so are the new minibuses that run many local bus services. However, most vans and minibuses run by schools, Scout groups, voluntary organisations, etc, and offered by hire companies use petrol.
Minibuses are harder to escape from than cars since they carry more people but have no more doors. Often the people carried are children or the aged or infirm, who are less mobile or have less presence of mind. I have a diesel car, and this is one of the reasons.