Speed LimitsThailand 2026: 120 km/h Is Allowed in the Right Lane Only
Cars may do 120 km/h in Thailand only on designated divided highway sections, in the right-most lane, which also has a 100 km/h minimum. Everywhere else the posted limit is lower.
Thailand’s 120 km/h limit is a lane rule as much as a road rule. On designated divided highway sections, cars may do up to 120 km/h in the right-most lane, and that lane also carries a minimum of 100 km/h.
Where 120 km/h applies
A 2021 ministerial regulation on vehicle speeds on designated national and rural highways allows cars up to 120 km/h on sections named for it. The Department of Highways applies it section by section on divided highways, and it has rolled the sections out in phases. The fourth phase, announced for 1 July 2023, added:
- Highway 1, Nong Khae to Suan Phruksasat Phu Khae junction, km 79+000 to km 101+600 (22.6 km, Saraburi), in both directions — from 1 July 2023.
- Highway 347, Pathum Thani Technology to Chiang Rak Noi interchange, km 1+000 to km 11+000 (10 km, Pathum Thani), in both directions — from 1 July 2023.
On these sections the Department of Highways added concrete barriers, rumble strips at the start and end of the controlled zone, and lane-by-lane signs.
How the lanes work
Thailand drives on the left, so the right-most lane is the overtaking lane, and it is the only one where 120 km/h is allowed. It also carries a minimum of 100 km/h. If you are not comfortable at 100, you belong in one of the other lanes, which have lower limits shown on the signs. Away from the designated sections, the posted limit is lower than 120 on every road, and the sign is what applies.
Check exact speed limits for your route
Open Speed Limit MapGetting help on the road
The Department of Highways runs a free 24-hour hotline on 1586, and the Highway Police can be reached on 1193.
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Related Questions
120 km/h for cars, under a 2021 ministerial regulation on vehicle speeds on designated national and rural highways. It applies only on designated sections, and on those sections only in the right-most lane.
Only on sections the Department of Highways has designated, which it has added in phases. The fourth phase, from 1 July 2023, added Highway 1 between km 79 and km 101.6 in Saraburi and Highway 347 between km 1 and km 11 in Pathum Thani, in both directions.
Yes. In the right-most lane where 120 km/h is allowed, the minimum is 100 km/h, so slower traffic has to keep to the other lanes.
The left. On the 120 km/h sections that makes the right-most lane the fast lane.