Explanation: You need to know the difference between the normal centre line and a hazard warning line. If there's a hazard ahead, the markings are longer and the gaps shorter. This gives you advance warning of an unspecified hazard.
Category: Road and traffic signs
References: The Official DVSA Guide to Riding: Section 7, Highway Code: Rule 127, Highway Code: Page 114, Know Your Traffic Signs: Page 62
