An industrial estate sells land, power, water and a permitting shortcut. None of those is what a truck meets. A truck meets a province, a road, a gate and a rule about who is allowed through it, and an estate can be excellent on the first list and difficult on the second.
That difficulty does not arrive as a complaint. It arrives as a rate. A carrier that has to send a truck a long way to reach you, wait at your gate, and drive home empty prices all three into the number it quotes, and it never itemises them. So the site decision, made once, sets a freight bill you then pay every month for as long as the plant runs.
The useful thing is that four of the five checks that matter are public, free, and take about an hour per candidate site. Here is what they are and how to read them.
The map is lopsided before you choose anything
At the end of July 2025 Thailand had 78 industrial estates in 17 provinces, of which 73 were operating. Five more had land under contract, 7,738 rai of it, and were not yet open. Sixty of the country's provinces had no industrial estate at all.
The concentration inside those 17 is sharper than the count suggests. The Industrial Estate Authority groups its estates into three operating regions, and the two that cover Chonburi, Rayong, Chachoengsao, Prachinburi and Sa Kaeo hold 159,483 rai of the national 202,383. That is 78.8% of Thailand's declared industrial estate land in five provinces.
This is not a point about prestige. It is a point about who else is on the road. An estate in that belt sits inside a dense two-way flow of goods that already exists, which means a truck arriving with your inbound material has a real chance of leaving with somebody else's outbound load. An estate outside it is usually one end of a long lane with nothing coming back, and the empty return leg is inside every rate you are quoted.
The bench you can call on a Tuesday
The Department of Land Transport publishes how many transport operators hold a licence, by the province that issued it. At the end of April 2026 there were 38,152 non-fixed-route goods operators nationally, which is the licence class you can hire.
| Registration area | Non-fixed-route goods operators |
|---|---|
| Central registrar | 2,268 |
| Chonburi | 1,778 |
| Rayong | 1,755 |
| Samut Prakan | 1,305 |
| Saraburi | 909 |
| Ayutthaya | 776 |
| Chachoengsao | 661 |
| Prachinburi | 592 |
| Samut Sakhon | 561 |
| Nakhon Sawan | 543 |
| Ratchaburi | 500 |
| Udon Thani | 395 |
| Songkhla | 389 |
| Sa Kaeo | 362 |
| Phichit | 294 |
| Lamphun | 203 |
| Ang Thong | 131 |
Read this carefully, because it is easy to over-read. The register records where a licence was issued, not where the vehicles work, and an operator registered centrally serves the whole country. A plant in Lamphun is not restricted to 203 companies.
What the number does tell you is the depth of the local bench: how many operators have a yard, a workshop and a driver pool near your gate, and can therefore answer a call on a Tuesday for a truck on Wednesday. That is a different question from how many trucks can eventually reach you, and it is the question that decides what a short-notice job costs. Chonburi and Rayong are second and third in the country. Ang Thong has 131 operators for the whole province.
The road outside the gate tells you two different things
The Department of Highways counts traffic at 2,739 points on the national network and publishes, for each one, the daily total and the share of it that is heavy vehicles. Nationally the median survey point is 12.56% heavy.
Take two estate roads with almost the same amount of traffic on them.
| Road and section | Vehicles a day | Heavy vehicles |
|---|---|---|
| Highway 116, Pa Sak to Sapung, Lamphun | 21,007 | 3.55% |
| Highway 331, Noen Mok to Plaeng Yao, Chonburi | 16,725 | 48.08% |
The first road carries a quarter more vehicles than the second. It is also, in freight terms, an empty road: fewer than four vehicles in a hundred are heavy. The second is a truck road, and at 48.08% it sits in the top 3% of survey points in the country.
Volume and composition are two separate problems and they cost you in different ways.
High volume, ordinary truck share is the Bangkok ring. The median survey point in Bangkok carries 81,423 vehicles a day and only 5.15% of them are heavy; in Samut Prakan, next door, it is 49,692 a day at 19.60%. Highway 34 at the Suvarnabhumi airport entrance carries 250,222 a day at 29.74% heavy. Your truck is not fighting other trucks there. It is sitting in a peak with everybody else, which means your delivery windows are stable in the middle of the day and unusable at each end of it.
Moderate volume, very high truck share is the estate belt proper. Highway 34 at Bang Wua to Bang Pakong in Chachoengsao carries 118,081 vehicles a day and 55.57% of them are heavy. Highway 2 at Tan Diao to Sap Bon, through Kaeng Khoi district in Saraburi, carries 121,874 at 59.60%. Chachoengsao's median survey point is 36.22% heavy, Ayutthaya's is 32.27%, Chonburi's 29.47%, Saraburi's 29.06%. On roads like these nothing is quick at any hour, junctions clear slowly, and the surface takes a beating that turns into roadworks later.
Neither is worse in the abstract. But they need different plans, and you should know which one you have bought before you build the delivery schedule around it.
What the road will legally carry, and who decided
Weight limits on Thai roads are not a single national number applied everywhere. Under Section 61 of the Highway Act, as amended in B.E. 2549, the highway director may announce in the Royal Gazette a prohibition on using a vehicle on a highway where its load weight or axle weight exceeds what is prescribed, or where the vehicle may damage the highway. It is announced road by road.
The part worth knowing at site-selection time is who has to approve that announcement, because it tells you what class of road you are standing on:
- The Director-General of the Department of Highways, for motorways, national highways and concession highways.
- The Director-General of the Department of Rural Roads, for rural highways.
- The provincial governor, for local highways.
There is also an emergency route. If an accident or an emergency damages the road or makes traffic on it unsafe, an officer appointed to control that highway can impose the restriction for a stated period simply by posting it openly at the place concerned. It does not go in the Gazette and there is nothing to look up. A weight restriction can appear on the road to your estate on a Monday morning as a sign on a pole.
The practical trap is the last few kilometres. The highway you looked up in the traffic file is rarely the road your gate opens onto. Between the trunk route and the estate boundary there is usually a shorter link of a different class, under a different approving authority, with its own limit and its own bridge. Drive it before you sign, and drive it in a loaded truck if anyone will let you.
Whether your gate is a customs boundary
Thai law defines an industrial estate as a general industrial zone or a free zone. Most estate land is the first kind. Of the 136,181 rai that Thailand's estates have to sell or lease, 5,430 rai is free zone land, which is just under 4%.
If your plot is inside that 4%, the estate gate is not only a gate. Bringing goods in and out, keeping them, and controlling their movement all run under the customs law on import, export and warehouse storage, with the customs penalties attached. Nobody may take goods out of a free zone without written permission from the Governor of the Authority or a person the Governor delegates. Goods leaving the free zone for use or sale in Thailand are charged duty, VAT and excise at the condition, value and rates in force on the day they leave, as though they had been imported that day.
And, in a line that matters more to daily transport than any of the tax ones, nobody may enter or remain in a free zone except with written permission and in compliance with the Authority's regulations, which the board is separately empowered to make covering identity cards, dress, and who may be inside at all.
Read that as a transport constraint rather than a legal one. A free zone plot means a substitute driver is not something your carrier can produce at 06:00 on a Monday, because the person is as controlled as the cargo. It also means every reversing, waiting and paperwork minute at your gate happens inside a customs process rather than beside one. That is manageable and thousands of firms manage it, but it has to be priced into the transport plan rather than discovered in month two. What each customs status actually does to a truck is the longer version.
What you can only get by standing there
Four checks are public. The fifth is not, and there is no substitute for going.
Go at shift change, not at eleven in the morning. Then count:
- How many gates the estate has, and whether goods vehicles are allowed through more than one.
- Whether the queue at the gate is on the estate road or backed out onto the highway. Backed out onto the highway means every arrival is unpredictable, not just the late ones.
- Whether there is a weighbridge, whether it is on the way in, and how long one vehicle takes over it.
- How wide the estate's internal roads are at the tightest point, and whether a full-length vehicle can turn at your plot without reversing onto a through road.
- What the security check consists of, and whether it applies to the driver, the vehicle, or both.
- Whether anything is closed at night, and if so what time the last vehicle can arrive.
None of that appears in a brochure and all of it is visible in forty minutes.
What the difference is worth
Say one candidate site costs 45 minutes a trip more than another: twenty minutes queueing at a single gate, and twenty-five crawling the last twelve kilometres on a road that is half heavy vehicles. It sounds like nothing.
Run six outbound trips a day for 250 working days and it is 1,125 truck-hours a year. A truck's legal working day is bounded, so at ten hours that is 112 vehicle-days, which is a bit under half of one truck's working year.
You will never see that as a line on an invoice. It arrives as a rate that is quietly higher than the same distance costs elsewhere, or as a seventh truck in a fleet sized for six, or as a carrier that stops bidding for your work. The site decision is where it was made.
The desk check, before the lease
| Question | Where the answer is | A bad answer looks like |
|---|---|---|
| How much freight already moves near this estate? | IEAT cumulative investment status, by operating region and province | An estate a long way from any other estate |
| How deep is the local carrier bench? | DLT transport operator counts by province | A province in the low hundreds, with your plant needing daily trucks |
| What is on the road at the gate? | Department of Highways annual traffic file, by route and section | A very high heavy share on a road with few lanes, or a very low one with no freight flow to join |
| What will that road legally carry? | Royal Gazette announcements under Section 61, plus a drive of the last few kilometres | The trunk road is fine and nobody can tell you about the link road |
| Is the plot inside a free zone? | IEAT's monthly land tables, which show free zone area estate by estate | Free zone status assumed rather than confirmed, with no plan for driver access |
Two of these also answer a question the brochure will not: whether the estate exists yet. Five of the 78 were still unopened at the last count, on land already under contract. An estate that is not open has no gate queue to measure and no carriers calling on it, and its road numbers are the numbers for a road that has not yet been asked to carry a factory.
Choosing an estate is a location decision, and where to put the building in the first place is the question underneath it. But the estate you can serve is not always the estate with the best brochure, and the difference between the two is published, in Thai, by three government bodies, for nothing.