Regulation No. 125 of the Economic Commission for Europe (ECE) lays down uniform provisions for the approval of vehicles with regard to the driver’s forward field of vision. The aim of this Regulation is to ensure that, when seated in the normal driving position, the driver has an adequate and unobstructed view of the road and the area in front of the vehicle, and that body components such as front pillars, the dashboard or installed equipment do not create hazardous blind spots. Compliance with these requirements plays an important role in preventing accidents caused by limited driver visibility and in improving overall road safety.​

The Regulation defines precise technical requirements for the design and construction of the front area of the driver’s compartment. Elements such as the shape and position of the front pillars (A-pillars), the dimensions and transparent area of the windscreen, the adjustment of the seat and the notional position of the driver’s eyes are all controlled. The vehicle must be designed so that, from the defined eye point, the driver can see the road surface and obstacles in front of the vehicle directly within specified angular limits, and that the angular obstruction created by pillars and fixed body components does not exceed the permitted values. In this way, blind spots in the critical forward field of vision are reduced as far as reasonably practicable.

The test procedures in Regulation No. 125 are defined in a clear and repeatable manner so that assessment of a vehicle’s compliance is transparent and reliable. During these tests, the position of the seat, steering wheel and driver is first set according to standard conditions. Using geometric reference points, the driver’s eye point is then established and the forward field of vision relative to the road and vehicle components is evaluated. The extent of obstruction caused by pillars, the dashboard and installed equipment is measured, and the vehicle is approved only if all required vision zones lie within the driver’s field of view and all obstructions remain within the specified limits.

TAT Laboratory in Iran is authorized to carry out the tests and issue certificates of conformity with ECE Regulation No. 125. The scope of this activity includes all measurements and evaluations necessary to verify compliance with the prescribed standards for the driver’s forward field of vision, functional safety and geometric conformity of vehicles. The laboratory uses advanced measuring equipment, dedicated software and up-to-date test methods to perform these assessments with high accuracy and efficiency. In doing so, the laboratory contributes to improving the safety of vehicles manufactured or imported in Iran and ensures that their design and construction minimize hazardous blind spots in the driver’s field of vision and provide a clear and reliable view of the road ahead.