Hook turns as a solution to the right-turning traffic problem

In traffic systems where driving is on the left, right-turning movements tend to be difficult to efficiently accommodate at signal controlled junctions. A hook turn is one potential solution for this. A hook turn is where a right turn is made from the nearside lane rather than an offside lane at a four-leg signalised junction. After entering the junction, the turning vehicle waits at a nearside position in front of the side road stop line, and then proceeds toward the exit arm when the side road signal turns green.

The research described in this paper uses microscopic simulation modelling in an innovative way to compare the traffic performance of a hypothetical hook-turn junction with an equivalent conventional junction with opposed right turns. The simulation model evaluated traffic performance under various combinations of demand flow, turning proportions, and signal timings.

It was found that hook turns reduced delays to through traffic from the same approach in nearly all cases. Overall junction performance depended on the scale of any increased delays to left-turning traffic and side road traffic resulting from the hook-turn movement. It is concluded that hook turns could be used much more widely than at present — including where driving is on the right — offering significant operational benefits in the right circumstances.