Lateral visibility at road intersection may be improved by a convex mirror. Mainly in built-up areas, where visibility on one or both sides of an intersection might be hampered by space limitations, such a device is striking because of its low cost as well as its actuated operating mode.

However, little information is yet available concerning its effectiveness as well as optimisation. The value of a convex mirror from a security viewpoint is experimentally assessed in a road junction where drivers who have to provide way may observe lateral traffic through a convex mirror. Comparison is made between mirror users as well as non-users, in relation to their provide way behaviour. The main searching is that the mirror appears as a device that enhances security behaviour and Direct FLT may be recommended as a traffic aid.