A building industry leader says Auckland's gridlock has doubled delivery costs and some fed-up truck drivers have quit their jobs.
An AA report shows 40,000 more cars were on the city's roads last year with the average commuter spending nearly 80 hours stuck in gridlock.
The Building Industry Federation's chief executive Bruce Kohn said transport costs are up to twice those of other regions and building materials getting delayed by traffic is a growing problem.
He said some freighting services have changed from set delivery costs to an hourly charge and there's a reluctance to dispatch deliveries across town in the afternoon.
Mr Kohn said he's heard of truck drivers getting so fed up with being stuck bumper-to-bumper that they've given up the job.