Thai long-distance coaches move fast, keep to a schedule, and take the space they need. On a two-lane highway a coach will sit close to the centre line, overtake anything slower than it, and expect the vehicle it is overtaking towards to move onto the shoulder. This is not aggression, it is the operating convention of the road, and once you know it the coaches are predictable. Until you know it, meeting a full-size double-decker coming towards you in your lane is one of the more alarming experiences available in Thailand.
Local buses are a different animal with a different problem: they stop constantly, often without pulling in, and passengers step down into the traffic lane. Both need room.
The coach: reading a big vehicle at speed
Why it drives the way it does
Inter-city coaches run to a published timetable over long distances, frequently overnight, on roads shared with slow trucks and farm vehicles. The driver's job is to maintain an average, which means overtaking constantly. A modern coach also has a lot of mass and a stopping distance to match, so once a driver has committed to a pass, there is no aborting halfway. The double-deckers are the ones to notice: very tall, they lean noticeably in a bend, and at speed they generate a wall of turbulence that on a scooter is a genuine shove.
The three-lane convention on a two-lane road
This is the single most important thing to understand. On a rural Thai highway with one lane each way and a wide sealed shoulder, the road is worked as though it had three lanes. A vehicle overtaking uses the middle of the road; the traffic in both directions shades outwards onto its shoulder to make room. Everyone gets through.
The reflex it requires is the opposite of the one most visitors bring. When a coach appears in your lane coming towards you, the instinct is to brake hard and possibly stop. What you should do is check your left mirror, move smoothly onto the shoulder, hold your speed, and let it pass. Braking hard closes the gap the coach driver is aiming at, and stopping in the middle of it is worse. Overtaking and undertaking on Thai roads covers the convention and its limits.
Check the shoulder before you move onto it. The convention assumes the shoulder is empty and it very often is not. Motorbikes ride there, bicycles ride there, pedestrians walk there, and slow farm vehicles use it as a lane. If the shoulder is occupied, you have nowhere to go, and that is the moment to lose speed early rather than late.
Being overtaken, and overtaking
Coaches overtake with very little warning and often with the horn. Hold your line and your speed. Do not speed up — this is the classic error, and it turns a two-second pass into a ten-second one with the coach stuck in the oncoming lane. Do not brake sharply either. On a motorbike, expect a substantial buffet as it goes by and a second one as it pulls back in; grip the tank with your knees and keep your arms loose rather than rigid, because rigid arms are what turn a gust into a wobble.
Overtaking a coach yourself deserves care. You need a great deal of clear road, and the coach may itself be about to pull out to pass a truck — which you will not see coming, because you cannot see past it. Do it decisively, on a long straight, and get well past before you move back in.
Watch the front wheel, not the body. The earliest signal that any large vehicle is about to change lane is the front wheel turning — it happens a beat before the body starts to move, and it is visible from behind. This is worth training yourself to look for; it buys you a second, and a second is a lot.
Local buses and the stopping problem
Urban and provincial buses stop frequently and are not fastidious about how. Expect a bus to stop in the live traffic lane rather than pull into a bay, passengers to step down into the road, and people to run across the road behind a stopped bus to reach it. The hazard is not the bus; it is the person you cannot see, emerging from in front of or behind it.
- Never pass a stopped bus quickly. Cover the brakes and pass at a speed from which you could stop for someone stepping out.
- Watch under the bus. You can often see legs moving on the far side before a person appears.
- On a motorbike, do not filter through the narrow gap between a stopped bus and the kerb. That is exactly where the passengers are.
- Expect a bus that has stopped to pull out again without a long look.
In Bangkok in particular, buses and motorbikes contest the same left-hand strip of road all day, which is one of the defining features of riding a motorbike in Bangkok. Cyclists have the worst of it, being slower than the bus and occupying the same space — cycling safely in Thai traffic deals with the tactics.
Minibuses and trucks
The white Toyota Commuter minibus is the workhorse of Thai inter-city transport. Modern ones are speed-limited and fitted with seatbelts as a result of tightened regulation, but they are driven hard: they overtake aggressively, follow closely, make heavy use of the shoulder, and stop suddenly at the roadside. Give them room and let them past.
Heavy trucks share the coaches' behaviour without the speed.
| Situation | What is happening | What to do |
|---|---|---|
| Truck crawling up a hill | Fully loaded and losing speed. It may be doing walking pace by the top. | Plan the pass early, on the lower slope, not near the crest. |
| Red rag on the back | The load overhangs the tailgate, sometimes by a long way. | Do not sit close behind; give extra room when passing. |
| Sugarcane or rice-straw truck | Overloaded and shedding material. | Keep well back. Cane on the road is slippery and comes off in bundles. |
| Truck straddling the line on a bend | Long-vehicle cut-in. It needs the extra width. | Hold back and let it complete the bend. |
| Indicator on for a long time | Frequently a signal to the vehicle behind about whether to pass, not a turn. | Do not rely on it either way. Look for yourself. |
That last one causes real confusion. In Thailand, as in much of Asia, a truck driver may use the left indicator to tell a following vehicle that the road ahead is clear to overtake, and the right indicator to warn against it. It is informal, it is not universal, and it is not something to bet on. Treat every indicator as ambiguous and make your own decision about the road ahead.
At night, and where you meet them
Heavy vehicle traffic increases sharply overnight, because that is when the freight moves and the long coach routes run — one of several reasons driving at night in Thailand is a different proposition. Trucks and coaches also carry a lot of decorative auxiliary lighting, which makes it genuinely hard to work out the shape, width or speed of what is coming. And they use the horn liberally at night as an approach warning rather than a rebuke — the same convention described in horn and headlight etiquette on Thai roads.
The trunk routes are where you meet the most of them. Highway 2, the Mittraphap road into Isaan carries an enormous volume of coach and freight traffic. Anyone driving Bangkok to Chiang Mai will spend the whole day among them. Expressways are much easier, because the passing happens in a lane rather than in the oncoming carriageway.
Frequently asked questions
A coach is overtaking straight at me. What do I do?
Check your mirror, move left onto the shoulder, keep your speed steady and let it through. Do not brake hard and do not stop. It looks worse than it is, and the manoeuvre works because everyone gives a little; the danger comes when one party does something unexpected.
Is it safe to overtake a long-distance coach?
It is legal and it is done constantly, but it needs more road than most visitors allow for. You are passing a long vehicle at speed with no view of what is in front of it. If you cannot see enough clear road to complete the pass without hurrying, wait.
What does it mean when a truck flashes its lights at me?
Usually "I am coming through" — the opposite of the courtesy flash used in much of Europe. Assume it is an assertion of priority, not an invitation, and do not pull out. Following distances here are shorter than in Europe across the board, too, so a large vehicle sitting close behind you is not necessarily being aggressive; let it past rather than speeding up or brake-checking it.
Are Thai coaches dangerous to travel in?
Passenger transport is regulated, modern coaches are speed-limited and fitted with seatbelts, and the major operators are professional. The risk sits with overnight driving, fatigue and the road environment rather than the vehicles. Wear the seatbelt.
Where should I be on the road when a bus is stopping?
Far enough out to be clear of an opening door and far enough back to see under and past the bus. On a motorbike, do not use the gap on the kerb side at all — go round the outside, slowly.