When may you cross double solid white lines?

Answer: B — When overtaking a road maintenance vehicle travelling 10mph or less

Under traffic laws, double solid white lines are used to indicate that lane changes are prohibited. This means that you should not cross the lines unless authorized by another traffic control device or in the case of an emergency. Option A is incorrect because it does not provide a valid reason to cross these lines. Option C is incorrect because it is only allowed in certain situations and should not be done without proper caution. Option D is incorrect because crossing these lines is not allowed at any time unless authorized. Therefore, option B is the correct answer because it allows for crossing the lines in a specific situation where it is safe to do so.