The government has enhanced safety measures by banning modifications to public transport vehicles, strictly controlling changes to the body and chassis. Those who alter vehicle conditions without notification face penalties including fines ranging from 2,000 to 50,000 baht and imprisonment for up to six months.
On 30 July 2026, Ms. Ploytale Lakshamisangchan, Deputy Spokesperson for the Office of the Prime Minister, announced that the government is advancing sustainable safety standards for public transport vehicles. The Department of Land Transport, as the safety standards regulator, has issued two official announcements: the first sets criteria and conditions for approving modifications or changes to passenger vehicle bodies (2025), and the second governs approval of modifications to vehicle equipment or components (second edition, 2025). Both announcements took effect officially on 1 July 2026. These measures ensure that public transport vehicles on the road have structurally sound, standardized, and highly safe bodies. Operators or vehicle owners wishing to modify or alter the vehicle body or chassis frame must comply with three key requirements.
Before proceeding: Operators or vehicle owners must apply for permission from the Department of Land Transport before starting any modifications to the vehicle body or chassis. They must prepare essential documentation, especially photos of the vehicle's condition before modification, design drawings, and certification from a licensed engineer (professional engineer level or higher).
During the process: Operators must supervise the modifications to strictly follow the approved design drawings. They must document the work with photographs showing both the vehicle’s exterior and interior, highlighting structural pillars, chassis, wheel axles, and steering linkages as applicable. Additionally, a licensed engineer supervising the work must provide certification and be photographed with the vehicle during modification.
If the modifications deviate from the approved design drawings, work must stop immediately, and corrections must be made to align with the approved design. Should design changes be necessary, the operator must submit a request for approval to the registrar and obtain permission before continuing. Furthermore, welding or modifying wheel axles beyond the manufacturer's design is strictly forbidden to ensure maximum safety.
After completion: Once modifications are complete, operators must compile evidence such as photos of the finished vehicle or chassis (including photos of the engineer with the completed vehicle or chassis) and certification from the engineer confirming the vehicle's structural integrity and compliance with approved designs. These documents must then be submitted to the Department of Land Transport for registration purposes.
Simultaneously, the Department requires body shops and chassis modification workshops performing such work to register properly. Eligible workshops must hold a factory license (Ror Ngor 4) and/or ISO9001 quality system certification for vehicle manufacturing or assembly. The list of registered workshops is available on the Department’s website (https://aeb.dlt.go.th/th). Workshops that fail to register cannot perform modifications or changes to vehicle bodies or chassis, nor can they process vehicle registration.
"For road safety, vehicle owners and users are urged to comply with the law. Unauthorized modifications without notifying the registrar will result in penalties under the Motor Vehicle Act (1979) and the Highway Act (1992), including fines from 2,000 to 50,000 baht, imprisonment up to six months, or both, and vehicle seizure for inspection," the Department emphasized.