There are more then 100,000 taxis, recognizable either by sign “Taxi” on the roof or by their number plates. They’re cheap and available virtually 24 hours a day. Meter taxis now predominate, but sometimes you may have to firmly ask them to switch the meter on to save negotiating later. Since taxis are cheap and the drivers work all hours in traffic that is legendary, a small tip is often appreciated. No need to negotiate the fare as all taxis in Bangkok are now metered . If he insists on giving you a fixed fare, instead of using the meter, it’s best to find another cab.
Don’t be surprised if the driver refuses to take you where you wish to go. Few taxi drivers understand English even if they do try to speak it. if you request to go on the express way, you have to pay the toll.