The loudest junction

Ask which junction in Bangkok is worst and you will get a confident answer. Ask ten people and you will get several confident answers, all different, all delivered as fact.

There are two published rankings. They do not share a single entry.

List one: the vehicles

The Bangkok Metropolitan Administration’s Traffic and Transportation Department counts vehicles at junctions. Data collected across 2567–2569 shows a number of Bangkok junctions carrying more than 100,000 vehicles a day, with the highest above 200,000.

The junction at the top of that list is the Lak Si Monument roundabout.

Two honest caveats, and the first is mine. I could not obtain the department’s table directly; these figures reach this article through a Thai consumer outlet reporting them, and the full ranking and the methodology are not in my hands.

The second caveat is the source’s own, and it is the more important one. The Thai coverage states plainly that the data does not cover every junction in Bangkok, and that it should be read as an overview of high-volume routes rather than a conclusion about which points are most congested at any given time.

That caveat is doing a great deal of work and almost nobody who shares the list repeats it.

List two: the complaints

A separate study measured something else entirely. Dataxet ran its DXT360 social listening tool across Thai social media and traditional media for the month of 1–30 November 2567, counting which Bangkok junctions people complained about.

The result:

Asok–Phetchaburi accounts for more than twice the complaints of the next junction and more than the bottom three combined.

Now put the two lists side by side

The Lak Si roundabout — the junction carrying more vehicles than any other in the city — does not appear in the complaints top five at all.

Asok–Phetchaburi — the junction generating four times as many complaints as Pratunam — is not reported as the volume leader.

Not one junction appears on both lists.

That is not a contradiction to be resolved. It is two instruments measuring two different quantities, neither of which is the one in the question.

What volume actually measures

Throughput. And throughput is a measure of success.

A junction moving 200,000 vehicles a day is working. Something has to be functioning reasonably well for that many vehicles to get through it in twenty-four hours. High volume tells you a junction is important, not that it is broken.

The genuinely worst junction in Bangkok might carry forty thousand vehicles a day, because that is all that can physically get through it. Low volume can be a symptom rather than a reassurance — and a junction that has failed so completely that people have rerouted around it will show a falling count.

Article 114 made a version of this point about Rama II Road: the reason it cannot be closed is that there is no parallel route. Volume measures how much a link carries. It says nothing about what it costs you to use it.

What complaints actually measure

Who is stuck there, and whether they are the sort of person who posts about it.

Look at where the complaint list clusters. Asok–Phetchaburi, Rama 9, Sathorn–Surasak, Pratunam, Lat Phrao. These are the central business district, the office corridors and the retail core — the densest concentration in Thailand of commuters who are young, online, on X and Facebook during the jam, and in the habit of narrating their day.

Lak Si sits on the northern edge of the city. Its two hundred thousand vehicles a day include a great many people who are not composing posts about it.

So the complaint ranking is a reasonably good measure of aggregate irritation among a specific population, and a poor measure of congestion. It is closer to a map of who has a smartphone and a grievance than to a map of where traffic fails.

Which is not a criticism of the study — it measured exactly what it said it measured, and said so. It is a criticism of how the result gets read, which is as an answer to a question it was never asked.

The number nobody publishes

The question people actually mean is: how much time does this junction cost me?

That has a proper measure — delay per vehicle, or average crossing time against free-flow time. It is not exotic. It is the standard quantity in traffic engineering and it is what a travel-time index is built from.

Navigation companies hold versions of it. Google, TomTom and Thai services like Longdo all derive junction-level delay continuously from phone and vehicle data. They publish city-level summaries, because those make headlines, and they do not publish junction-level tables.

The BMA counts vehicles. Social listening counts complaints. Delay per vehicle is measured constantly, by private companies, and is not public.

So the one number that would answer the question everybody is asking is the one number nobody puts out.

The question worth asking, which I cannot answer

Here is the thing that follows, and I am raising it as a question because I have no evidence for it.

If official attention — officers posted, signals retimed, works prioritised — responds to complaint volume, then it responds to the loudness of the people stuck rather than to the severity of the jam.

I want to be clear that I have not established that this happens. The Thai source names which police station is responsible for each junction, which is useful and is why the table above includes it. It says nothing about how resources are allocated, and neither do I.

But it is a reasonable thing to want to know, and the fact that the complaint list is the more widely circulated of the two makes it worth asking. A junction with 200,000 vehicles a day and no social media presence is, at minimum, easier to overlook.

Why this keeps happening

This site has now found the same shape often enough to name it.

Article 85 The tourists nobody counts found Thai domestic tourism systematically undercounted, because the counting method was built around travellers who book accommodation. Article 145 The ballot proves nothing found a selection system whose records contain nothing decisive, so the truth had to be assembled from eighty thousand pages of testimony. Article 81 The fine nobody paid found traffic fines whose enforcement depended on a mechanism that did not function.

In each case the same thing: the quantity that matters is hard to observe, an easier proxy is measured instead, and the proxy is then discussed as though it were the thing.

Volume is easy — you put a counter at a junction. Complaints are easy — you run a keyword query. Delay is harder, it belongs to companies rather than to the city, and so the public conversation is conducted entirely in proxies.

And the proxies are not neutral. Volume flatters junctions that work. Complaints flatter the districts where the complainers live.

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Practically

If you are trying to plan a route, neither list will help you and you should not use either. Both are aggregates over months. Congestion at a Bangkok junction is a function of the hour, the day, the weather and whether it is the end of the month.

Use live routing, and trust it over your own conviction. The strongest finding in this article is that confident opinions about Bangkok junctions — including yours, and mine — are formed from a handful of memorable bad experiences rather than from anything measured.

If you are choosing where to live or take an office, the volume data is the more useful of the two, because it tells you which junctions are structurally load-bearing rather than which ones annoyed people last November.

If you want to report a specific problem, the Thai source is genuinely useful: junction traffic management sits with the Traffic Police Division under the Metropolitan Police Bureau, through the station covering that area, and the table above lists which station holds each of the five.

Common misconceptions

“Asok is the worst junction in Bangkok.” It is the most complained-about junction in one month’s social media. That is a different claim.

“The busiest junction is the worst one.” High volume means a junction is moving a lot of vehicles, which is evidence that it works.

“There’s official data on which junction is most congested.” There is official data on how many vehicles pass. Delay per vehicle is measured by navigation companies and is not published at junction level.

“Low traffic counts mean a junction is fine.” It can mean the opposite — that capacity has failed, or that people have rerouted.

“These lists are wrong.” Both are accurate about what they measured. The error is in reading either as an answer to “which junction costs me the most time?”