A double solid white line indicates that the line may not be crossed, overtaking is permitted if it can be performed safely without crossing the line. Solid lines can be crossed in certain specific conditions (entering premises, overtaking a stationary vehicle, overtaking a vehicle, pedal cycle or horse travelling at less than 10 mph, or when directed to do so by a police officer). A solid white line with a broken white line parallel to it indicates that crossing the line is allowed for traffic in one direction (the side closest to the broken line) and not the other.