These vehicles MUST NOT be used on motorways (see Rule 253). They should not be used on unrestricted dual carriageways where the speed limit exceeds 50 mph (80 km/h) but if they are used on these dual carriageways, they MUST have a flashing amber beacon. A flashing amber beacon should be used on all other dual carriageways (see Rule 220).
- Road Traffic Regulation Act 1984: Section 17(2) & (3)
- The Road Vehicles Lighting Regulations 1989: Regulations 17(1) & 26