The truck-driver whose load smacked into the Penrose overbridge on Monday was the second operator this year to collect the concrete beam, and the 10th since 2013. There is little room for error when passing beneath the heavily-reinforced structure, designed to act as a first line of defence against over-height loads. Heavy traffic regulations put the maximum height above ground of a load at 4.25m and permits an additional 25mm for tarpaulins, lashings, straps, chains, covers and similar temporary tie-downs. The 10 tonne digger that hit the Penrose bridge had a 4.57m clearance to negotiate. Flashing lights on the overpass should have tipped the driver off that he had a problem, but for whatever reason the early warning system did not register with the contractor.

The costly collision has raised issues of liability. The trucking company could get a repair bill for the bridge, but the city wears the cost of disruption.

Michael Barnett, head of the Chamber of Commerce, argues this is wrong and believes that a level of accountability would ensure that heavy loads met the physical limits of the motorway network.

A number of solutions have been suggested. The road beneath the bridge could be lowered, or the overpass raised. These options would not come cheaply, nor would a requirement for trucking firms to hold liability policies to cover themselves in the event of a bridge strike claim. But clearly some response is necessary, given the way an accident at any of the sensitive points of the system tends to ripple across the entire network.


The transport industry needs to lift its game. The overpass is a known hazard, and its clearance plainly indicated and familiar to users of the Southern Motorway.

If a farmer burning off a pile of stumps allows the blaze to destroy neighbouring property they can face severe financial penalties under the Forest and Rural Fires Act. Designed to protect valuable assets, the legislation imposes a strict liability on those who start forest fires, irrespective of negligence. Anyone who causes a fire will almost certainly be held liable for the costs of the damage plus the costs of fighting the fire unless they can prove that their actions were not the cause. Drivers would be less likely to forget about the Penrose bridge, or any other low obstructions above Auckland's motorway arteries, if they faced similar liabilities to negligent farmers.

It would be going too far to hold an operator liable for a city-wide shutdown, but the prospect of a financial hit ought to bring about a change of attitude.

A few years ago, following a spate of bridge strikes, the transport industry cooperated with a campaign called "Check your height". Since then the volume of traffic on the motorway network has grown immensely, as have the disruptive impacts of blockages. Some stoppages are unavoidable, but other shutdowns are preventable. Bridge strikes ought not to happen.