Heavy Haulage

Roadworks detours are not always viable for oversize

By Jonathan Bhana-Thomson, chief executive,  Heavy Haulage Association.

Roading contractors are becoming ambitious in the way they go about the upgrading and renewal of the roading network, and this will often result in full closure or one-way closures on main State Highway routes.

But, simply put, there is not enough analysis being conducted of the impact of this on freight and specifically oversize freight.

Especially this construction season it is very noticeable that for a number of reasons, that the solution for light vehicles and freight using the main travelling routes is to detour them onto side roads with greater distances to travel in order to bypass the work area.

Undertaking this type of traffic management can be for good reasons. The first may to be do with better safety on the worksite, with bigger safety zones around the work areas where the actual work is being done.

A second may be an effort to undertake more significant works all at one time – examples of this include the regular overnight closure of the Remutaka Hill road where multiple work tasks at different locations can be completed at the same time to reduce the overall impact of the work to be undertaken on users of the road.

Then a third reason could be to do with reducing the waiting time for traffic at either end of a longer section of a stop-go traffic management situation – as diverting traffic onto alternative routes can actually lead to fewer delays and frustration.

These are all good reasons for diverting vehicles to alternative detour routes to lessen the number of vehicles on the road in the work area, or to remove them completely in the case of a full road closure.

The issues with this approach that we as an association have is that often the detour routes are not suitable for freight vehicles, let alone oversize freight vehicles, and they may actually result in more safety issues for road users.

Our advice for roading contractors and their traffic management planning works is the following.

Early discussion with the freight industry

When planning various options about road improvements or road renewals that include longer roading detours and closures, then early discussion with freight industry representatives is key.

There are only a small number of freight advocacy organisations, including ourselves, and we can enter early discussions over how viable alternate routes are. Also, the duration in terms of length and time of an alternative route is a key consideration. And please undertake this consultation way before you go public with the plan.

Testing of the route is an option

The contractor involved in a recent major project near Inglewood, after some prompting, took the step of driving the route with a freight operator – and filming it – to see how safe it would be for trucks to use the route. This proved a useful basis for identifying that these back roads were not that suitable for freight to use, but light vehicles could still safely undertake this route. So overall it was a good compromise for trucks to be able to stay on the main road and wait for the Stop/Go operation to let them through.

Specifically assess any detours for oversize

For freight that is oversize – be it wide, high, or long or travelling on an overweight permit, there are a multitude of reasons why a route may not be suitable. These include road width and clearance restrictions of light and power poles; trees and vegetation close to or overhanging the road; lower than usual overhead wires, and bridges that have weight restrictions or high sides. All these factors need to be assessed in conjunction with the oversize transport sector to see whether it is viable that the detour route is suitable – or whether a different arrangement needs to be put in place for accessing through the worksite with prior arrangement.

Through these steps, the outcome for both the road freight transport sector and the road contracting industry will have better outcomes.

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