I could be mistaken, but I'm sure that the one and only time I've been in that "Asda" lane, the traffic lights have a 4th light at the bottom, a green arrow signifying a right turn back towards the bridge.
Shutting off the lights would be better for traffic, however, I believe that it would be more dangerous for at least a few weeks because of peoples selfish "just go" attitude.
I also agree with Colin that the "dead end" road from the Asda mini roundabout should go to a left only give way junction for people going back out over the bridge. Those lights stay green enough for about 3 cars to get out or 1 lorry, not to mention that once 2 cars are in the middle lane, every one going up Belmont Road has to join the queue of people going up Ross Road.
I wouldn't mind betting that that "roundabout" has the record for most traffic lights in the country.
EDIT:
I just drove past, there is indeed a right turn green arrow on the Asda lane... what they have done is added MORE lights so that if you turn right, you have about 1 car's depth before more red lights, basically the same as it used to be but they've duplicated the junction and lights.
I did start to count the PAIRS of lights on that one roundabout, but got lost and confused after 18.
