Roadworks on Highway 121 reduce traffic. To single lane, raising safety concerns

Drivers on Highway 121 — the canal road running into the city — have been caught off guard by a sudden lane reduction near the NACC Chiang Mai office in Don Kaew, Mae Rim, where ongoing roadworks have narrowed two lanes down to one.

A site inspection found that the central median has been extended into the right lane in a triangular formation, with construction still incomplete. The pinch point sits just beyond a curve, meaning drivers — particularly those unfamiliar with the road — are braking sharply upon encountering the bottleneck, raising concerns about rear-end collisions.

Signage at the site identifies the works as part of the Highway 121 Efficiency Improvement Project (Don Kaew–Ton Payom section), with a construction period running from 27th December 2025 to 24th July 2026 at a cost of 47.48 million baht. The project will ultimately widen the road from four to six lanes across both directions.

Sittharit Preedanon, Director of Chiang Mai Highway District 2, explained that construction has been temporarily suspended pending approval from the Royal Irrigation Department. The current lane configuration is a stopgap measure during that waiting period. Once approval is granted, work will resume and the full lane width will be restored.