Tava Olsen: Here is a hot solution to Auckland's traffic congestion

Traffic on the Southern Motorway. Photo / Natalie Slade

Tava Olsen is Professor of Operations and Supply Chain Management at the University of Auckland business school.

Auckland doesn't need to wait for better public transport - the right toll system could ease gridlock now.

Anyone who regularly drives in Auckland knows how an accident on the harbour bridge can cause delays throughout the motorway network, sometimes for an hour or more. What people understand less acutely is that this massively amplifying ripple-effect works in reverse. On some routes, a mere 1 per cent fall in usage could lead to a 10 per cent decrease in transport delays.

Following a joint council-government report exploring road toll options, there seems to be broad acceptance across the political spectrum that, at some point, tolls will be introduced in Auckland to ease congestion. But many argue major improvements in public transport improvement must come first, so commuters have viable alternatives to driving.

Auckland undoubtedly needs better public transport - more frequent, more reliable, with extensive linkages. But that will take years, and there's a solution we can import from California right now. The system involves HOT lanes (High Occupancy/Toll lanes) in which buses and vehicles with two or more passengers travel free but single-occupancy vehicles pay a toll.

Tolls vary dramatically as road congestion changes, and the current price of using a road is posted at each entrance to the lane. The prices are set so that the lane always flows at around the speed limit, and the charging is done electronically through in-vehicle devices, so there is no need to stop and pay the toll.

If you are travelling at rush hour but you really need to make that 9am meeting with the boss, you might be willing to pay the charge to take the fast lane. But if you are flexible, you could plan your trips for off-peak times, when tolls will be lower.

HOT lanes could be introduced almost anywhere a bus lane exists, and they could also help justify adding more bus lanes, notably to the Northwestern Motorway, which would improve the public transportation network.

Introducing HOT lanes is also about future-proofing our network. The lanes could be used by autonomous (self-driving) vehicles, which will be able to travel safely at closer distance than regular drivers.

Measures to overcome Auckland's gridlock should focus on changing behaviour rather than merely gathering revenue. But revenue from HOT lanes could be used to fund more public transportation options, creating a virtuous circle.

This would work better than Mayor Len Brown's idea of introducing a flat toll for entry to the motorway. It is likely drivers would simply switch to suburban roads, shifting congestion to rat-runs.

Cordons - imaginary boundaries within which tolls apply - are probably not suitable for Auckland, which is not as compact as the European cities where they have been effectively used.

Transport systems face similar issues to supply chains where companies doing what is best for themselves may create inefficiencies.

You need to set up a mechanism to make the system more efficient for everyone.

We don't need to wait for public transport to improve: we could get started making Auckland's roads smoother-flowing and more efficient now.