Motorists have been warned to expect heavy traffic congestion as the Bangkok Metropolitan Administration (BMA) will close and demolish three key traffic flyovers during construction of the Orange Line electric train route, which starts on Friday.

The BMA on Wednesday announced its plan to close and dismantle the flyovers at the Pratunam, Ratchathewi and Sutthawat intersections to make way for the MRT Orange Line's western section, from Bang Khun Non to Min Buri.

Closures and traffic diversions are set to begin on Friday with traffic barriers being put in place to manage traffic flow around Pratunam and Ratchathewi intersections, where work on the Orange Line's Pratunam and Ratchathewi stations will start.

The demolition of the Sutthawat and Ratchathewi flyovers is scheduled for Jan 6 and 15 respectively while the Pratunam flyover will be dismantled in March 2026.

Construction of a new Pratunam flyover will take place between April and November in 2026.

The BMA is concerned about severe traffic expected due to the closure of the flyovers which are in some of the capital's busiest areas.

It has been coordinating with district offices to ease traffic management and ensure road sections will be available for use during the day, with the work to take place mainly at night.