"John Rowland" wrote in message
...
The traffic lights here have three (traffic) phases:
1) turn right from the main road
2) forward or left from the main road
3) forward, left or right from the minor road
...in that order. Every other junction which I know has these three phases
has them in the opposite order.

Does anyone know why this junction is different?

It is not different from several I know. This sequence would allow traffic
turning right from the main road to clear the area of the junction on the
minor road before that on the minor road needs to go straight ahead into it.
Depending upon the traffic volumes and any restrictions further down the
minor road, that could sometimes reduce the probability of crossing traffic
from the minor road obstructing straight ahead traffic on the main road.

Colin Bignell