The 39th Bangkok International Motor Show is now on at Challenger Muang Thong Tani.
There are many luxury cars as well as Toyota, Honda etc
There are mini vans that can transport cheaply from Central Bangkok.
For example yesterday at 4pm I took the mini van from outside the Royal Hotel on Ratchdomnoen road (near our agency) to Challenger, about 25km for 45 baht. Dropped off outside the entrance
