§ Mr. Atkins
[holding answer 2 February 1990]: Car parking signs which are off the highway are subject to permission by local planning authorities under the Control of Advertisement Regulations. There is no legal limitation as to their size.
Car parking signs which are located within the highway are covered by the Road Traffic Regulations Act 1984 and the Traffic Signs Regulations and General Directions 1981. The traffic speed on a road will determine the height of the letters used on the sign. Practical considerations and the amount of information to be included will determine its overall size.