UN R51 Vehicle Noise Emissions | UN Regulation | UNR 0051 |
UN R117 Tire Rolling Sound Emissions, Adhesion on Wet Surfaces, and Rolling Resistance | UN Regulation | UNR 0117 |
Quiet Road Transport Vehicles | Regulatory Project | QRTV-GTR |
UN R138 Quiet Road Transport Vehicles | UN Regulation | UNR 0138 |