Why is it recommended to cross rail tracks at an angle of at least 45 degrees?

Answer: C — To reduce the risk of tire slippage

Crossing rail tracks at an angle of at least 45 degrees is important primarily to reduce the risk of tire slippage. When you approach and cross the tracks at a steep angle, you minimize the contact that the tires have with the tracks, which are often slick, especially when wet. This angle helps to ensure that the motorcycle can maintain traction, as the tires are less likely to slip on the narrow, potentially slippery surface of the tracks. Additionally, crossing straight on can cause the tires to get caught in the grooves of the tracks, which can lead to a loss of balance or traction. By adopting the recommended angle, riders can improve their stability and help ensure a safer crossing. The other aspects such as maintaining control and visibility, while important for overall safety, are secondary to the primary concern of preventing slippage during this type of maneuver.