OPP want to remind motorists to move over where they can, or slow down and pass with caution when they see a police or other emergency vehicle stopped at the side of the road. Not every OPP vehicle is black and white with a set of roof lights. The OPP use a number of different vehicles, some have subdued markings while others are completely unmarked. They all use red and blue lighting to alert motorists to either pull over or stop. Traffic stops can occur at any time, but officers will always try to stop where it is safe.