Why hitch? Hitch-hiking as an art, or science, is almost as old as the motor car. Originally the concept was largely synonymous with hiking. You started walking, and if a car came along you put out your hand; mostly you ended up hiking the whole way. From this casually optimistic pursuit, hitching has evolved into a fast, comfortable form of travel in some parts of the world. Elsewhere it remains one big adventure. Hitching has many virtues. It is the most environmentally sound form of motorised transport, since the hitcher occupies an otherwise empty space. Socially it can be rewarding, enabling you - indeed obliging you - to talk to people whom you would not normally meet. Financially it is highly advantageous: hitching allows you to travel from A to B for free or next to nothing, whether A is Aberdeen or Auckland, and B is Birmingham or Bucharest.

Yet standing for hours at a dismal road junction with the rain trickling morosely down your neck as heartless motorists stream past is guaranteed to make you question the wisdom of trying to thumb a ride. And placing yourself entirely in the hands of a complete stranger can be harrowing. Some travellers dislike the degree of dependence upon others that hitch-hiking engenders. Hitch-hiking can also be enormously lonely. Expect the elation of getting the ideal lift to be tempered with stretches of solitude and frustration and bear in mind that motorists rarely give lifts out of pure philanthropy. Your role may be to keep a truck driver awake with inane conversation, to provide a free English lesson or to act as a sounding board for a life history. But no two rides are ever the same. Techniques and conventions of hitch-hiking vary considerably around the world, most notably the divergence between fast, money-saving hitching in the West and the slower and more chaotic practices of lift-giving in less developed countries.

The West and the Developed World

In Europe, North America and Australasia, hitching can be an almost mechanically precise way of travelling. The main criteria are safety and speed. To enable a motorist to decide whether or not to pick you up, he or she must be able to see you and stop safely. The driver must evaluate whether he or she can help you, and if you would enhance the journey. Make yourself as attractive as possible by looking casual but clean. Hitching in a suit raises driver's suspicions (normal dress for an average hitcher being denim). Looking as though you've been on the road for a year without a wash is equally counter-productive. So freshen up, choose a suitable stretch of road, smile and extend your arm. The actual gesture is a source of possible strife. In most parts of Europe and North America, the raised thumb is understood to be an innocent gesture indicating that a lift is needed. Elsewhere it represents one of the greatest insults imaginable. A vague wave in the general direction of the traffic is safest.

Never accept a lift with anyone who is drunk, high or otherwise gives you cause for concern (e.g. by squealing to a halt in a cloud of burning rubber after crossing six lanes of traffic to pick you up). Turning down a ride is easier said than done, especially if you have been waiting for six hours on a French autoroute and night is falling, but try to resist the temptation to jump into a van full of dubious characters. If you find out too late that you've accepted a dodgy ride, feign sickness and ask to be let out. It sometimes works.

Some offers should be turned down simply because they are not going far enough. Hitching through Germany from the Dutch border to the Polish frontier can be done in a day, but is best achieved by discriminating in your choice of lifts. Refuse a ride that would take you only 20 km to the next town. By hopping from one autobahn service area to another, you can cover ground extremely quickly.

All kinds of gimmicks can help you get rides more easily. The most effective device is a destination sign. Road systems in developed countries are often so complex that a single road may lead in several different directions. The only commonly enforced law on hitching is the one forbidding hitching on motorways, freeways or autopistas. By using a sign you minimise the risk that the driver who stops will want to drop you at an all-motorway junction such as those on London's M25 or the Boulevard Peripherique in Paris. Make your destination request as modest or as bold as you wish - from London you could inscribe your sign 'Dover' or 'Dar Es Salaam', but always add 'Please'.

Sophisticated hitchers concentrate their attention on specific cars. The real expert can spot a Belgian number plate at 100 metres. He or she will refuse lifts in trucks (too slow), and home in on the single male driver, who is easily the most likely provider of a lift. So good is the hitching in Germany that if you vowed to accept only lifts in Mercedes, you would still get around. Neighbouring France, in contrast, is hell for hitchers, as is much of southern Europe and Scandinavia.

Hitch-hikers fare well in the newly liberated nations of eastern Europe, especially Poland. It has a Social Autostop Committee - effectively a ministry for hitch-hiking - which provides incentives for motorists to pick up hitchers.

Having taken Lou Reed and Jack Kerouac's advice, and hitch-hiked across the USA, I would hesitate to recommend the experience to anyone. While the chances of being picked up by an oddball or religious fanatic in Europe are tiny, in the States almost every lift-giving motorist is weird and not necessarily friendly. New Zealand could not be more different nor less threatening: if you need a place to stay, just start hitching around nightfall, and a friendly Kiwi will almost certainly offer you a ride and a room. In Australia, the hitcher is the object of greater abuse than anywhere else, with insults (and worse) hurled from car windows alarmingly often.

One exception to the hitching lore of the developed world is Japan. Western hitch- hikers are picked up, usually very quickly, by one of the extremely considerate local drivers. In the absence of any other information, he or she will assume that you want to go to the nearest railway station. But upon learning that your final destination is hundreds of kilometres away in, say, Kyoto, the driver may feel duty bound to take you all the way there.

Japan is one place where women can feel comfortable hitching alone. The conventional wisdom is that women should never hitch alone. Single women hitchhikers are all too often victims of male violence. Nevertheless, women continue to hitch alone, and get around without problem; some maintain that safety is largely a question of attitude: if you are assertive and uncompromising, you survive.

If 'real' hitching does not appeal, ride-sharing agencies exist in many countries. The idea is simply that travellers share expenses, and often the driving, and pay a small fee to the agency that arranges the introduction. Be warned, however, that there is no guarantee that a driver you contact in advance will not turn out to be a psychopath or a drunk as you hurtle through the Rocky Mountains or central Australia.

The concept of hitching can be extended to boats and planes. Hitching on water can involve anything from a jaunt along a canal in Europe to a two-month voyage to deliver a yacht from the Canary Islands to Florida. And in countries where private flying is popular, rides on light aircraft have been successfully procured.

Less-developed countries

At the other extreme are the dusty highways of Nigeria or Nicaragua. In the Third World, the rules on hitching are suspended. Almost any vehicle is a possible lift- provider, and virtually every pedestrian is a potential hitch-hiker. Amid such good- natured anarchy, hitching is tremendous fun.

You have to accept any form of transport, from a horse and trap upwards. To make the most of opportunities, it helps to be adept at riding side-saddle on a tractor engine, or pillion on a moped for one.

Purists who regard paying for petrol as contrary to the ideals of hitch-hiking, and dismiss the idea of asking a driver for a ride as capitulation, can expect a miserable time in the Third World. Definitions of what constitutes a bus or a taxi, a truck or a private car, are blurred. Sometimes the only way to reach a place is by hitching, and local motorists may exploit their monopoly position accordingly.

El Salvador's transport system has been devastated. Everyone hitches, and you are expected to pay the equivalent of the fare on the (notional) bus. The same applies in large swathes of Latin America, Africa and south Asia. Unless you have insurmountable moral objections or a serious cash-flow crisis, you should always offer something for a ride. More often than you might expect, the ride will cost nothing more than a smile. In Indonesia, for example, the Western hitch-hiker is a curiosity, to be taken (temporarily) home and paraded in front of friends and relations as an exotic souvenir. You too can become an instant celebrity.

Cuba has massive transport problems, some of which are solved by an intriguing form of mass hitch-hiking. Little old ladies and large young louts join forces to persuade passing trucks to stop, or pile into a Lada saloon driven by a grumbling member of the bourgeoisie.

In such places hitching is at its simplest and most effective. Thumbing a ride enables you to see corners of the world that might otherwise remain hidden, and to meet people whom you would surely pass by. And, in the final analysis, there are worse ways to travel than being chauffeur-driven.