A trial to assess how to solve traffic jams on the £21m Postwick Hub had to be abandoned - because of the tailbacks of vehicles it created.
Council bosses were having a rethink over a section of the junction, off the A47 to the east of Norwich, because of rush hour tailbacks building up at a roundabout.
Norfolk County Council is considering installing a new segregated left turn lane because of the problems with traffic coming from the Great Yarmouth direction and heading into Thorpe St Andrew.
To simulate the impact such a lane would have on other traffic, the council planned to carry out two tests over two weeks, with temporary traffic lights trialled on the roundabout, so traffic crossing the old bridge could go through the roundabout without giving way.
But the first of the two tests, carried out at about 8am on Monday, had to be rapidly abandoned, because of the jams the trial created.
John Birchall, from Norfolk County Council, apologised to the drivers who found themselves caught up in Monday's jams. He said: 'Unfortunately the traffic built up so quickly at the signals that we couldn't hold it for long enough for a proper trial. We gave up after 40 minutes, and won't be trying that again.
'We are looking at other ways of testing a segregated left turn, but it won't involve traffic lights, and won't be in the next day or two.'
Mr Birchall said a possible option for the next test could see a lane cordoned off to separate the traffic turning left at that junction.
He said: 'We are looking at ways we could do the test, but we haven't got a firm decision yet. We want to get a fair test before we decide what we can do.
'We need to get a period where we can see how a segregated lane would affect the rest of the traffic. If it shows there is no significant benefits, then there's no point us doing it.'
Traffic modelling had been carried out ahead of construction and the scheme had gone through a public inquiry, but Mr Birchall said it was always difficult to predict how drivers would use stretches of road once they were opened.
Critics who opposed the junction recently said they feared traffic problems would get even worse once the controversial Northern Distributor Road, which will connect to the Postwick Hub, opens.
What do you think of the Postwick Hub? Write, giving full contact details, to Letters Editor, Prospect House, Rouen Road, Norwich NR1 1RE or email EDPletters@archant.co.uk
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