Bangkok’s Double-Deck Expressway Plan Sparks Safety, Toll and Pollution Fears

A multibillion-baht expressway rising above the already elevated Sri Rat route was supposed to untangle traffic from Ngamwongwan to Rama 9. Instead, it has entangled policy-makers, engineers and residents in an increasingly heated debate over safety, transparency and the future cost of driving in Bangkok.

Under the Concrete: Voices from Below

Opposition coalesced last week when representatives of the Expressway Authority of Thailand labour union joined forces with the Thailand Consumer Council, echoing fears that a second-storey roadway could turn everyday alleyways into emergency traps. More than 1,000 families who live beneath the structure worry about sudden closures that might block ambulances, fire engines and even ordinary motorcycles trying to reach home. Their anxiety is magnified by the continued absence of the full environmental impact assessment—a document officials acknowledge exists but have not released. Community spokesperson Thiwalak Pumwaree asked why the public must keep guessing about vibrations, dust and construction schedules when the paperwork is already on an office shelf.

The Concession Chessboard

Behind the engineering diagrams lies an intricate financial bargain. The current proposal allows Bangkok Expressway and Metro (BEM) to pour roughly ฿34 B into the project in return for a 22-year, five-month extension of two lucrative toll concessions. Critics argue that such an arrangement could lock drivers into higher tolls, reduce competitive bidding and undermine public value for money. Negotiations are being steered by a small EXAT project cell, fuelling allegations of a "closed room" deal. Government sources counter that the extension enables a promise to cap Stage 1 and Stage 2 tolls at ฿50—a politically appealing headline ahead of New Year—but opponents note the cap arrives years before the debt-laden structure even opens.

Engineering Risk and Recent Memories

Traffic engineers who normally stay out of politics have stepped forward after a March 2025 beam collapse on another project killed two workers and shook public confidence in elevated construction. The double-deck design requires columns to be drilled beside pillars that already carry thousands of vehicles each hour. Specialists warn that night-time lane reductions during pile driving could create new accident hotspots. EXAT insists that a comprehensive safety plan, including smart sensors and 24-hour monitoring, will be mandatory, yet union members say standard operating procedures are still "in draft form" and no timetable for independent audits has been published.

Environment: The Unopened File

While the National Environment Board signed off on an EIA summary in late 2024, neither academic appendices nor modelling data have surfaced. Leaked slides suggest that dust particulate levels under existing ramps already flirt with PM2.5 red-zone thresholds; adding a second layer of traffic could push readings well beyond legal limits. Noise projections reportedly show decibel spikes day and night, and residents fear the heavier shade will deprive ground-level shops of both sunlight and customers. The Department of Health has quietly begun a parallel study on respiratory ailments in the corridor, but its initial findings are likewise under wraps.

Imagine If the Money Went Elsewhere

Urban-mobility researchers point out that a fraction of the budget could fund signal-free bus rapid transit corridors along major arteries feeding the expressway, upgrade Easy Pass gantries to barrier-less technology or remove two notorious Sri Rat toll booths that throttle traffic each evening. Rail advocates add that overlapping catchment zones for the Orange, Blue and Yellow MRT lines will soon give commuters multiple rail options if authorities accelerate park-and-ride facilities and station feeder buses. In their view, spending on asphalt rather than rails simply keeps Bangkok locked into a car-first paradigm.

What Happens Next

The cabinet is expected to consider the file before Songkran. Approval would trigger final contract drafting and a construction start as early as next year, aiming for operation in 2030. Union leaders promise escalating action if the full EIA and the draft public-private partnership contract remain undisclosed. Community groups are preparing legal petitions under the Official Information Act and vow to stage roadside vigils under the shadow of the very pillars that could soon carry a second motorway. The only certainty for now is that Bangkok’s most ambitious expressway since the 1990s has become a litmus test for how Thailand balances infrastructure ambition, public oversight and the everyday right to breathe and move freely in the capital.