Auckland's Dominion Rd could have bus lanes running up and down its centre, just as trams did until the middle of last century.
The idea has been raised by Auckland Regional Council chairman Mike Lee, amid uncertainty over kerbside bus lanes introduced in 1999.
Although he has criticised a decision by Auckland City's transport committee to consult the public on whether to open the lanes to all vehicles with one or more passengers, committee chairman Ken Baguley agrees running buses along the centre of Dominion Rd merits consideration.
The council is planning a $50 million-plus upgrade for the road, which will include widening long stretches by up to 2m.
Even so, space will remain tight through intersections with Balmoral and Valley Rds after the abandonment of a proposal for bus loops, which would have turned shopping centres into islands.
"If you could treat the bus as a tram and have it going on its own set of lights through one central lane, far less road is going to be required by the bus lane," Mr Baguley said.
Mr Lee's criticism came at the Auckland Regional Transport Authority's launch of new branding for Dominion Rd and Mt Eden Rd as high-frequency "b.line" routes, along which passengers are promised a bus at least every 15 minutes between 7am and 7pm on weekdays.
Although buses already run far more often at peak times, authority chairman Rabin Rabindran says many Aucklanders are unaware of public transport improvements. Clearly marking those and other high-frequency routes should help to coax them out of their cars.
Mr Lee welcomed the initiative, for which NZ Bus has branded about 50 of its more modern vehicles as b.line specials.
But in a speech he described Auckland City's proposal to open up the bus lanes as retrograde.
"It is most unfortunate that at the very moment Dominion Rd has been chosen as a flagship route for bus improvements in Auckland, the city council is considering removing bus lanes and allowing cars with just one passenger into those lanes," he said.
"I hate to say to my friend Ken [Baguley] that in our opinion that will undo all the superb work and investment that Auckland City has undertaken in recent years.
"It will lead to delays, and that goes against our common mission.
"We need to understand that compromising the effectiveness of the Dominion Rd bus lanes is in direct conflict with the ARTA b.line initiative."
The concept has been a success in Vancouver, where almost 50,000 passenger trips a day are taken on three rapid-transit b.line routes; one includes 2.5km of busway in the middle of a main street.
Mr Lee said that if there was a problem with bus lanes along the edges of Dominion Rd, conflicts with vehicles pulling out of driveways or side streets could be removed by running buses down the middle.
Traffic lights could be used for passengers to reach platforms in the middle of the road.
"Such a system would cope with far higher numbers of buses than the current system or the proposed retrograde T2 idea [of allowing cars with two or more occupants into bus lanes]."
He said afterwards that the system could also future-proof Dominion Rd for light railcars once passenger demand grew beyond the capacity of buses.
Mr Baguley said the public would be invited to make submissions next month on the bus lanes. "If the number of buses using Dominion Rd prohibits a T2 and we can get evidence of that, I guess there won't be a T2."
He said the review followed an unacceptable staff proposal for the lanes to be reserved for buses for 24 hours a day, rather than just at peak times. A trial along Tamaki Drive also indicated the T2 concept was a better use of road space.
City Vision councillor and Campaign for Better Transport member Graeme Easte said Dominion Rd was a far busier bus corridor than Tamaki Drive. And even there, general traffic faced longer delays because of the trial.
"We shouldn't ruin it by slowing the buses for no great advantage for the cars."
* 6km from Eden Tce to Roskill South.
* Former tram route.
* Site of Auckland's City first bus lanes.
* Carries 7200 bus passengers a day.
* Up for $50 million-plus upgrade 2012-2016 as arterial route between Southwestern Motorway and central Auckland.
* Public consultations on upgrade and review of bus lanes starts next month.