1.4.3.1. Tests shall also be carried out at various speeds, the lowest being equal to 30 per cent of the maximum speed of the vehicle and the highest being equal to 80 per cent of that speed. In the case of vehicles equipped with a speed limiter, this limiter speed shall be taken as the maximum speed of the vehicle. The maximum practical performance figures shall be measured and the behaviour of the vehicle shall be recorded in the test report. Tractors for semi-trailers, artificially loaded to simulate the effects of a laden semi-trailer shall not be tested beyond 80 km/h. a0c0