Like in Many Cities in the world, Bangkok has it's share of Toll Ways and Expressways and Highways with tolls and when you are riding the tour vans going around, the price of the tolls going to the various tour destinations is included in the tour price. the only problem will be when riding taxis and when you want to reach your destination fast, then the tollways are a good option but you must pay the tollway fee of the taxi besides the taxi fare! tollway fee starts at 25 baht for short distances and the average tollway fee around bangkok is 25 to 55 baht for taxis and that you must pay the tollway fee at the toll booth once you arrive at the toll booth.
according to wikipedia:
Most of the toll roads in Thailand are either within Greater Bangkok or originated from Bangkok. They are called expressways, tollways, and motorways. Two government agencies under the Ministry of Transport, namely the Expressway Authority of Thailand (EXAT) and the Department of Highways (DoH), own networks of toll roads. Some are operated by the agencies themselves; others are operated by private concessionaires. EXAT is in charge of Chaloem Mahanakhon Expressway, Si Rat Expressway, Chalong Rat Expressway, Udon Ratthaya Expressway, Burapha Withi Expressway and Kanchanphisek Outer Ring Road (southern section). DoH is in charge of Uttraphimuk Tollway (formerly Don Mueang Tollway), Motorway No. 7 (Bangkok-Chonburi), and Motorway No. 9 (Kanchanphisek Outer Ring Road - eastern section).
Expressway in Bangkok
Its the largest road in Bangkok, have a small traffic but its go to use to faster.
First Photo: Bangkok Express-Way
Second photo: View of Bangkok from Express-Way
Third photo: Bangkok Express-Way
Forth photo: Bangkok Express-Way
Fifth photo: Bangkok Express-Way