THE SkyBus would get its own lane on CityLink and the Tullamarine Freeway and have its fares slashed under a government plan to combat peak-hour congestion that is increasingly blowing out travel times between the airport and the city.
But the proposal, which involves turning emergency lanes into bus lanes on the freeway and the Bolte Bridge and putting SkyBus on a myki fare, is being challenged by CityLink operator Transurban, because it would limit its toll revenue, and by Melbourne Airport, because it would reduce its car parking profits.
Details of the Melbourne Airport bus rapid transit project were revealed to Fairfax Media through freedom of information. The aim of the Transport Department project is to put in place a ''first-stage mass transit link to the airport in advance of a rail link''.
SkyBus was designed to provide a 20-minute run between Southern Cross Station and the airport but is consistently failing to do this during peak periods, with times blowing out to as much as 51 minutes in the morning and 59 minutes in the afternoon peak.
A study by engineering and consulting firm Parsons Brinckerhoff found that ''the future will see a continuation of the significant but relatively gradual degradation of travel time on the CBD-airport bus route''.
Melbourne Airport has indicated that this would be a significant reduction in revenue.
The study provided three options for improving travel times, with the department's preferred one involving creating an express bus lane and putting SkyBus on a public transport fare.
A 2011 briefing to Transport Minister Terry Mulder said: ''Putting SkyBus on a Met fare and enforcing express lanes would significantly reduce travel time on the express lanes without significantly affecting travel times on the non-express lanes.''
It added that more detailed traffic modelling would need to be done.
But the briefing, by former director of public transport Hector McKenzie, warned that airport management had signalled it would expect financial compensation.
''The bus rapid transit study has also estimated a … drop in car parking at Melbourne Airport with the estimated … increase in Skybus patronage,'' Mr McKenzie wrote.
''Melbourne Airport has indicated that this would be a significant reduction in revenue, and that compensation through an appropriate access charge would be expected.''
Figures on the estimated drop in car parking revenue and increased SkyBus patronage were deleted from documents provided to Fairfax Media.
SkyBus transports about 2 million passengers annually, and the figure is growing. If the trend continues, it will carry 4 million people a year by 2026. It is privately run with a portion of profits going to the state government. It charges $17 for a one-way trip.
SkyBus is understood to pay Melbourne Airport an access fee of $1.50 per passenger. The airport would seek to impose a much higher fee. An Australian Competition and Consumer Commission report last year found that Melbourne Airport made an annual $87 million profit from car parking.
The SkyBus lane would be created relatively cheaply by removing the emergency lane and nominally narrowing the other lanes.
However, Transurban is believed to be bargaining hard to ensure it is not locked out from any extra lane on CityLink. A spokeswoman said: ''Transurban supports any further augmentation of CityLink for the benefit of all the travelling public.''
CityLink currently has right-hand transit lanes for high-occupancy vehicles, but this is unenforced and ignored by many drivers. The proposed bus lane would carry a SkyBus every 1½ to three minutes during peak times, carrying about 1200 passengers an hour, with a maximum 20-minute time.
The study warned: ''Negative comments from motorists may ensue from the use of motorway lanes by what would be 40 buses per hour or less.''
Its proposed solution was to also allow taxis and limousines into the lane. The study also proposed the lane could be used for new high-speed bus routes with major park-and-ride stations from suburbs including Essendon Fields, Westmeadows and Kealba.
Public Transport Victoria spokeswoman Andrea Duckworth said: ''The government does not have immediate plans to install myki readers on SkyBus or widen CityLink.''
Ms Duckworth said the investigation into a bus rapid transit lane was part of the government's $6.5 million airport rail link study.
''PTV's focus is on completing the rail link study, including identifying the best route for a rail line,'' she said.
Melbourne Airport spokeswoman Anna Gillett would not say how much compensation the airport would seek from the government if the bus lane plan ate into its car parking profits.
''We have been working with the government on the rapid bus transit lane study … and support any initiatives that will assist SkyBus to minimise travel time and also help to reduce congestion on the Tullamarine Freeway,'' Ms Gillett said.
The northern section of the freeway is currently used by about 42,000 vehicles a day, which exceeds its 40,000-vehicle capacity.