Under what condition can you legally cross a double white line?

Crossing a double white line is generally prohibited as it indicates a no-overtaking zone; however, there are specific circumstances where this rule can be legally bypassed. One of these circumstances is when overtaking cyclists or horses that are traveling at a speed of 10 mph or less.

This provision acknowledges the need for safety while accommodating slower-moving road users. Overtaking in this situation is allowed to ensure that cyclists and horseback riders can proceed without obstruction, while also allowing drivers to pass safely. The importance of maintaining distance and ensuring the safety of everyone on the road, particularly vulnerable road users, is the underlying reason for this exception.

In contrast, overtaking stationary vehicles, approaching traffic lights, or parking in designated areas do not provide valid reasons for crossing double white lines, as these actions do not align with the rules meant to ensure road safety and traffic flow.