Local buses, mostly operated by the Bangkok Mass Transit Authority (BMTA), are the cheapest but also the most challenging way of getting around, as there is a bewildering plethora of routes, usually marked only in Thai. If you can speak Thai you can call 184 Bus Route Hotline. Bus stops usually list only the bus numbers that stop there and nothing more. They are also subject to Bangkok's notorious traffic, often terribly crowded, and many are not air-conditioned. If you want to get somewhere quickly and are not prepared to get lost, the buses should be avoided (remember that taxis are cheaper than most local buses in the west). However, they make for a good adventure if you're not in a rush and you don't mind being the centre of attention.

But for the intrepid, and those staying in Khao San Road, the biggest backpacker's ghetto where buses are the only practical means of public transport, the best online resource for decrypting bus routes is the official BMTA homepage, which has up-to-date if slightly incomplete listings of bus routes in English but no maps. You can also ask your guesthouse about buses to where you are going. If you're going between Khao San Road and downtown, white air-condition bus number 511 (white number sign only , never get in the 511 yellow sign, it will bring to suburb via express way) is probably your best option to get to Sukhumvit. As a printed reference, the Bus Routes & Map guide (50 baht) by Bangkok Guides is another option.

The hierarchy of Bangkok's buses from cheapest to best can be ranked as follows:

• Mini Bus (small green bus), 7.50 baht flat fare. Cramped, no air-con, no fan, famously daredevil drivers, not advisable for more than short hops.

• Cream-Red bus , 7 baht flat fare. More spacious and fan-cooled (in theory). Unlike other buses, some of these run through the night (1.50 baht surcharge). These buses are BMTA run. Good news! Now the government has launched a campaign "Free fare buses for citizens" to reduce the people living cost, so people (locals and foreigners) can get in buses that have a white sticker with blue words "Free for citizens" and no need to pay anymore. These free of charge buses and ordinary buses leave in alternate order. This campaign will last this July 2009.

• White/blue bus , 8.5 baht flat fare. Exactly the same as the red buses, but cost one baht more. These buses are owned by private entities operated in conjunction with BMTA.

• Blue/White air-con , 13 baht for the first 8 kilometers, up to 21 baht max. These buses are quite comfy. The yellow striped buses are privately owned while the Blue/white buses are BMTA owned.

• Orange air-con ( Euro II ), 14 baht for the first few kilometers, up to 24 baht max. These are all BMTA-run, newer, and more clean and comfortable.

• Pink/white micro-buses - not quite so common away from the city centre - these are air-conditioned, modern and only allow seated passengers (making them harder to use at rush hour as many won't stop for you). Flat fare is 25 baht which is paid into a fare-collection machine located next to the driver - exact fare only.

Buses stop only when needed, so wave them down (arm out, palm down) when you see one barreling your way. Pay the roaming collector after you board and keep the ticket as there are occasional spot-checks. Press the signal buzzer (usually near the door) when you want to get off.

Two further pitfalls are that buses of the same number may run slightly different routes depending on the color, and there are also express way services (mostly indicated by yellow signs) that skip some stops and may take the expressway (2 baht extra).

Airport buses allow luggage (backpacks and suitcases), but regular buses do not. Anyway, this rule is mild enforcement.

A regular bus service is provided by the Bangkok Mass Transit Authority (BMTA) and its contracted operators throughout Bangkok as well as to its outskirts during 4 a.m. – 11 p.m. and around the clock on certain routes. Public buses are plentiful and cheap, with a minimum fare of 7 baht to most destinations within metropolitan Bangkok. Half of them are free of charge. Air-conditioned buses have minimum and maximum fares of 13 and 24 baht, respectively. Air-conditioned micro-buses charge a flat fare of 25 baht all routes. A Bus Route Map is available at bookshops. For more information, call 184.