In which of these cases, does the engine brake turn off automatically?
Show the correct answer
Correct answer
C. When the ABS system turns on
Explanation
The question is about the situation in which the engine brake (exhaust brake) switches off automatically. This happens when the ABS system is activated - answer C.
The Road Traffic Act requires a vehicle to ensure reliable use of its braking devices. The engine brake and the retarder brake through the drive wheels - when ABS detects on a slippery surface that the wheels are starting to lock, the control unit switches off these additional brakes so that they do not make the drive axle skid and do not interfere with the way ABS meters the braking force. Engine speed below 1500 rpm (answer A) and vehicle speed below 30 km/h (answer B) are not a general rule - the thresholds depend on the design, and at low engine speed the engine brake simply works less effectively. That is why you should not count on engine braking on ice.
Legal basis: Art. 66 para. 1 point 5 of the Road Traffic Act (Prawo o ruchu drogowym)