Council transportation manager Martin Parkes told the Bay of Plenty Times that traffic modelling had shown that the tidal flow system would make congestion worse, not better.
"It would only work if there were three lanes along Turret Rd. We're doing a feasibility study to assess whether a third lane could be added to the existing Turret Rd bridge."
Parkes said if that was shown to be feasible, the council would then assess whether a tidal flow system would be worthwhile.
He said widening Turret Rd to four lanes did not have a firm date or budget, but it would not start until after widening and other improvements to 15th Ave had finished. And work on 15th Ave would not start until after the Bayfair to Baypark (Bay Link) project had finished because two main roads could not have major construction taking place at the same time.
A council report last year stated that the Hairini Link underpass, due to open later this year, would not resolve congestion issues on Welcome Bay Rd, or downstream on Turret Rd and 15th Ave.
Curach said three-laning Turret Rd bridge had earlier been ruled out was because it could not sustain the extra loading. "If they come back and say 'Yes you can put three lanes across the bridge', that would be a brilliant interim solution."
However, if the answer was no, then he believed further traffic studies should be carried out on his and Mr Wassung's collaboration. It would mean holding back cars on the quiet peak-time direction until the queue had reached 20 or 30 cars and then allowing them to cross the bridge.
Traffic coming from the busy direction would temporarily be narrowed to one lane.
A report last week to councillors from council chief executive Garry Poole said the unprecedented increase in cars queuing along Welcome Bay Rd on weekday mornings was a pressing issue.
"The extent of the traffic build-up is a surprise. We have been trying to understand exactly what's going on so that we can hopefully implement some practical solutions."
Poole said the Bay Link project may be the reason why many people who previously used Hewletts Rd now appeared to be using Maungatapu and 15th Ave to reach the city.
The underpass construction was also compounding problems for Welcome Bay residents.
He said traffic data censors were being installed on Welcome Bay Rd and Ohauiti Rd to help understand the change in traffic numbers.
"We will also be undertaking queue monitoring on Welcome Bay Rd."
A technical working group was meeting this week to see if anything could be done immediately to alleviate traffic pressure. It would also consider measures within the next weeks or months, Poole said.