In provincial Thailand, hiring a car can be a good and relatively cheap way of getting about. Hiring a car with a driver/guide is marginally more expensive, but is perhaps a better idea as it will mean avoiding all the problems associated with driving yourself about. Avis, Hertz and other international car hire agencies are well represented in Thailand, and there are also many local companies about. The local companies are always cheaper, but have the disadvantage that the cars may not be properly insured (even if they tell you otherwise). Your insurance from home might not cover being involved in an accident from renting a car/motorbike, so it's worth checking that before you leave.

One way rental is a possibility with bigger companies but expect it to cost a lot more. It's a good idea to always fill up the tank before you bring the car back too, as petrol is cheap and the fee you would otherwise be charged is expensive.

You are almost always asked to leave your passport as a deposit for any vehicle that you want to rent, but there is obviously a risk in doing this. If you negotiate, some places will let you leave travellers cheques or cash instead (local hire firms are generally more flexible than international ones). Bear in mind that if you have any sort of problem and have left your passport, you will be in a very weak position when it comes to negotiating how much the damage costs. Your embassy and/or the police may be able to help you, but don't count on it.

Check a vehicle thoroughly before hiring it as they are not always in pristine condition, particularly the cheaper ones. Point out any existing damage or scratches before you hire, or don't be surprised when they try to charge you for them later.

Most of the roads and highways are in good condition, and have two or three lanes on each side. Be aware that the bigger vehicle has right of way on Thai roads, and so be prepared to get out of the way quickly if there is a large truck behind you. Passing on blind corners is not uncommon. Most road signs are written in Thai and English, though some are only in Thai (like 'Stop' and 'Give Way'). Buy a decent road map before you set off, and remember that Thai words aren't always romanised consistently (e.g. Petburi road and Phetchaburi road are one and the same). Driving at night is not a good idea, as many of the truck and bus drivers are overworked and forced to drive throughout the night - and resort to using amphetamines (yah-bah in Thai) to keep themselves awake.

For most people, hiring a car and driving yourself about in Bangkok would be little short of a nightmare. The traffic is some of the worst in the world, roads are confusingly signed and some of the driving standards exhibited are questionable to say the least. Hiring a car with a driver or using taxis would be a much better idea.

Hiring a motorbike is quite a common activity, particularly on the southern islands and in some of the northern towns. Especially in the north, this is a great way to get out into the countryside to see the 'real' Thailand. It's possible to hire in Bangkok too, but inadvisable unless you are a very experienced rider - accidents are all too common.

Places such as Ko Samui and Pattaya have a lot of foreigners renting motorbikes who have never ridden one before, which can make for hazardous driving conditions. Expect to be stopped at least once by the Thai police if you do a lot of riding, as you are technically breaking the law if you:

• Don't have a valid international driving license, with motorcycle entitlement.
• Don't have a valid health insurance policy.
• Aren't wearing a helmet.
• Don't carry your passport around with you at all times - this is obviously a bit of a problem if you left it as a deposit

If you are stopped, the policeman is likely using one of these rules as an excuse to extract a bribe, normally around 200B or so but it can potentially be very expensive depending on your situation. Paying up is the best course of action, as you really will be in trouble if you end up being taken to the police station.

Some of the roads on Ko Samui and Ko Pha-Ngan are very dangerous, particularly the road from Thong Sala to Hat Rin on Ko Pha-Ngan. Be careful, as accidents in this area are very, very common - the number one cause of deaths of foreigners in Thailand. If you've never ridden before, some of these roads really aren't the best places to learn.

If you have to misfortune to get into an accident, it's likely to be judged as your fault (even if it wasn't) and you will be expected to pay for any damage caused (to vehicles and people) there and then. If someone is injured, the asking amount will be increased to cover the treatment costs - these amounts are definitely up for negotiation, strange as it may seem. Any serious injuries and deaths will definitely involve the police being called - you may still be able to get out of trouble by paying enough money, but it's not certain.

If you plan on driving in Thailand, bring both an international driving license and your home driving license. You won't (usually) be asked for either of them by the renting companies, but having both will likely be a great help should you happen to get into any legal difficulties.