5. When in the fully raised position the barriers shall be inclined towards the carriageway at an angle of between 5 and 10 degrees from the vertical. No part of either barrier or of any attachment thereto which is less than 5 metres above the level of the carriageway shall be horizontally displaced from the nearer edge of the carriageway by less than 450mm. No part of any barrier or any attachment thereto which in either case is less than 2 metres above the level of the footway shall normally be horizontally displaced from that edge of the footway further from the carriageway by less than 150mm.