Motorists are making traffic jams worse by ignoring warnings about delays, a transport expert says.
University of Canterbury transport engineer Professor Alan Nicholson said drivers don't divert to alternative routes unless they can see the queue, even if they've already been warned of a blockage.
Professor Nicholson has been researching how traffic can be more efficiently managed after accidents and breakdowns.
Though a $170,000 grant from the New Zealand Transport Agency, and working with Dr Glen Koorey and postgraduate students, the project modelled traffic flows on part of Auckland's northern motorway.
Professor Nicholson said by looking at real data of traffic movement following an incident at the Northcote interchange, they were able to observe how traffic flows were affected on the motorway.
He said motorists ignored an overhead message warning citybound drivers to exit the motorway at Tristram Rd until it was too late. "They didn't start to leave the motorway until quite some time after the blockage had occurred. People delayed leaving until they could see there was a queue of vehicles right ahead of them."
The research project is looking a the use of Intelligent Transport Systems and incident management plans to help adapt traffic plans after an accident.
Traditionally, traffic management after an incident was ad hoc, relying on educated guesswork on how to redirect traffic, he said.
"Our research uses computer simulation models, together with collected field data, to reproduce the effects that a range of incidents will have on the network.
"The model simulates both the road network and the traffic signal system, which automatically adjusts traffic signal timings at our intersections, based on traffic demand."
But he says the solutions will only work in some situations -- there's still no way of avoiding a major snarl-up after a rush-hour incident on the motorway.
"In peak hour congestion, no amount of tweaking will improve an unexpected incident situation."
NZME.
