Question This white sign means: Answers You should slow down and move to the right lane. Stay in the right lane if you are driving more slowly than other traffic. Slower traffic must exit on the right. Explanation A white, rectangular sign indicates that you must obey important rules. This sign means that drivers should allow the left lane to remain open, when possible, for passing and for faster traffic. Take a FREE Practice Test Now This questions appears in the following tests: California Practice Test