Rollover root causes

There is more to heavy vehicle access than simply from the driveway of the distribution centre, the retail site, or the vehicle showroom.

It’s not always speed that causes heavy vehicles to roll, but it is often what lays beneath these heavy road warriors.

From what’s currently happening on the ground, it doesn’t appear that we, and our planners, are learning from prior errors.

In fact, it is apparent that the designers of the goods distribution hubs, coupled with local government planning approvals, continue to repeat the same errors.

Recently, I challenged a Council Mayor about the design of a particular roundabout where there have been several heavy vehicle rollovers.  The short response was: ‘we know about that roundabout, however the engineer who designed it has left employment with the Council’.

So how does that fix the inherent infrastructure problem?

Learning from mistakes

In design it’s human to make mistakes, with the key being to learn from those errors and not make the same mistake again.

I can recall a number of examples, where the consideration for delivering raw products by trucks at a facility was much less than basic, but the same facility had a five-star rating for out-loading finished product.

This was where facility designers may have overlooked how best to get the raw product safely on to the sites.

Another example wa, where a livestock facility was promoted as being designed to receive B-doubles, while it already had B-triples and Type 1 road trains operating there.

It was decided to allocate a light vehcile parking area opposite the unloading/loading docks, which reduced the turning space for heavy vehicles.

Another example is of the click-and-collect shopping services, where, in one case, the new space saw support columns encroaching into the reversing line of the delivery dock.

One has to question the level of consideration of the real world reversing of heavy vehicles. It may be a simple enough issue, but one that can have serious consequences.

Today, due to sub-optimal planning, there are sites, possibly designed 40 or 50 years ago for a semi-trailer with an overall length of 15 metres or less, where the truck has to park on the public road, from which a fork-lift has to unload pallets, or a car carrier unloading its cargo to a dealer, from the roadway. These are dangerous situations for all road users, but at a time when the shipping and delivery of goods is a necessity.

Thankfully there are tools to predict the swept path of various vehicle combinations, although most are less than perfect for predicting reversing manoeuvres however, the use of a swept path analysis program needs to have an in-depth understanding of heavy vehicle driving.

An example of the successful prediction of a vehicle’s swept path was the design of a facility and workshop, to receive Type-1 Road Trains in regional New South Wales.

The successful design layout was completed with the assistance of the Department of Transport and Main Roads’ Vehicle Path, or VPath, where the actual swept path performed by the driver was within 100mm of the VPath prediction.

Despite that there are many examples where road managers seem to be overly optimistic of a vehicle’s ability to perform tight manoeuvres when accessing a delivery site.

Solutions

The following key issues need to be considered to address the current status of heavy vehicle ingress and egress.

Look forward and plan: Consider the size of the next generation of freight vehicles; a B-double today will likely be a B-triple in ten years.

Ensuring access: Access from the roadway to a site must be legally compatible, so the truck doesn’t proceed into the counter flow traffic due to parking arrangements for light vehicles.

Tyre friendly kerbs: The kerbing on access and egress needs to be tyre friendly, not sharp rises on the mountable verge of roundabouts that can cause tyre sidewall damage.

Room for deliveries: Provide ample room and clearance for a delivery truck with a splayed clearway from the dock, including not positioning bulky installations (compactors), within 400mm of the dock reversing splayed clearway; not planting gardens that obstruct truck drivers’ vision; facilitating reverse manoeuvres for an articulated combination that on the driver’s side.

Size matters: Reversing a B-triple is typically easier than reversing an A-double, especially if the trailing units of the A-double are shorter.

Be aware: All operators and site managers need to be aware of the challenges the driver faces at the pick-up and delivery sites, and  address those issues.

A good starting point to address access to goods delivery sites would be the development and implementation of various industry Codes of Practice.

However, these, and any related Technical Procedures or Austroads Guides, are only beneficial if regularly updated and appropriately referenced.