Buses within Chiang Mai are actually Yellow or White Songthaews that travel a set route.
For buses to destinations within Chiang Mai Province use the Chang Pheuak bus terminal Tel: (0 5321 1586; Th Chotana). Price - to the Chang Pheuak terminal you should be able to get a Songthaew at the normal 20B per person rate
For buses outside the province use the Chiang Mai Arcade bus terminal Tel: (053 266 4804), also called New Terminal. Price - From the town centre, a túk-túk or chartered Songthaewto the Chiang Mai Arcade terminal should cost 50B to 60B;
Bus is the number one transportation for long distance trips in Thailand. The network is very dense, the bus rotations are numerous. There are public buses the less expensive and many private companies offering VIP bus offering a little more comfort and better service. Most buses are in very good condition and air conditioned. The average speed depending on the selected bus is around 60 to 70 km/h.
By bus, you can go almost anywhere you want in Thailand. This is the most used public transportation in the country. The price is very affordable especially for public buses and increasing if you choose VIP Buses, which often offer more comfortable seats, a bottle of water and one or more meals included in the price.
Sometimes, movies or TV shows are broadcast on board, but only in Thai. Farangs (foreigners) are of course a minority. Buses are less suitable to discuss or share with the people than the train because passengers often take the opportunity of the trip to sleep.
You can hail the buses like taxis from the border of the road and you just buy a ticket once on board. No need to go to the bus terminal. Similarly if you want to get off at any time during the trip, just alert the driver and bus attendant and they will drop you off.
If you visit the islands, you can buy a bus + ferry ticket directly. There is no limit on luggage and no extra fee to pay if you have a heavy one. Each city has its bus terminal where you can go and buy your tickets. While travelagencies also offer to purchase bus tickets, take them directly to the counter bus terminals, it allows you to pay less and compare the prices of different the bus companies or find schedules that are more suitable.
Bangkok has three major bus terminals, each with its region of destination.
Mochit, (Northern Bus Terminal) the largest one is the gateway to towns in the North and also offers some departures for cities in the South or the East,
Sai Tai Mai (Southern Bus Terminal) serves the South and
Ekkamai (Northestern Bus Terminal) the East of the country. Sometimes terminals are located just outside the city and you will have to take a taxi, tuk tuk, songthaew or other means of transportation to reach them.
Note that there are persistent rumors of thefts in bus leaving from Khao San Road and sometimes in buses during the ferry transfer. However, apart from these two cases, the thefts are extremely rare if not nonexistent.
Many travellers could be dicing with death when journeying on a double-decker this Songkran
Before riding on a double-decker bus you should read this article in th Bangkok Post Newspaper. These buses are dangerous (Not built for safety-Build in Thailand)