If the commercial vehicles were forced to run on petrol, the running costs would skyrocket! Diesels have better economy and low-end torque hence they are ideal for load-lugging activities. And the LTA have allowed CNG buses and cabs on the roads.Originally posted by alamat:bullshit from lta lah. otherwise how do you explain the so many cabs and commercial vehicles on our road? what about those from malaysia? mind you, these vehicles spend a lot more time on the road than normal cars.