[Neil]

I have seen them as well. They seem very close to the actual motorway. So when they change to green you wont have much time to accelerate before you have to get of the slip road. I always thought the idea of the slip road was to allow you to reach the same speed as the cars in the 1st lane. I think it will cause accidents when slow cars are pulling into lane 1 forcing other cars to move into lane 2.