Yellow and red striped flag

The yellow and red striped flag warns riders that grip on the track ahead has changed. The cause may be oil, coolant, water, gravel, sand or other debris on the surface. It is shown at the marshal post before the affected section.

When you see it, ride with extra care: reduce speed, avoid sudden braking or acceleration and pick a line that avoids any visible contamination. Unlike a yellow flag, it does not by itself forbid overtaking in most rules, but always check the series regulations.

The flag is common in road racing and circuit track days. In some series it is also shown at the start of a race to indicate that rain has made the track slippery.