How can a driver safely test for icy road surfaces?

Gently pumping the brakes is a safe method for testing icy road surfaces because it allows the driver to monitor the traction without risking loss of control. This technique helps to determine how well the vehicle can stop or slow down without locking up the wheels, which can lead to skidding on icy conditions. By applying gentle pressure to the brakes and then releasing, the driver can gauge the responsiveness of the vehicle while maintaining a level of control, which is crucial in slippery conditions.

The other options are less safe and effective for testing traction. For instance, a hard brake application can lead to wheel locking, resulting in a thorough loss of control on ice. Accelerating quickly is not advisable since it can cause the vehicle to spin out or skid, making it impossible to accurately assess the grip of the road surface. Driving at normal speed does not provide the necessary caution required in icy conditions and can increase the risk of accidents if the road is indeed slippery. Therefore, gentle pump braking is the prudent choice for evaluating road traction in icy scenarios.