Coloured street signs are to be used to help identify different no-stopping zones in a move which is claimed to be a world first. The Department of Transport yesterday announced its decision to adopt an advisory coding system to improve the recognition of existing regulatory signs for restricted zones. Under the improvement scheme, the poles of the sign posts will be painted with designated colours - red, yellow and green - to indicate different areas. Sign posts in green represent the 7am to 10am and 4pm to 7pm stopping ban while posts painted red denote a 7am to midnight no-stopping ban. Yellow sign posts will be used to represent a ban from 7am to 7pm daily. The colour of posts in other restriction zones will remain grey. 'Motorists can easily and immediately identify, even from a distance and during night time, different stopping restrictions with the help of the coloured sign posts,' said Wong Kam-tong, engineer of the department's Road Safety and Standards Division. He said an early trial of the new system in Causeway Bay has been considered successful. Mr Wong expects the scheme to be completed by next July and to cost $1.5 million.