Could you roll over today?

Important information for truck/trailer drivers (licence classes 3 and 5)

Around a third of heavy vehicle crashes in New Zealand involve a rollover, of which more than half are truck-trailers.

Rollovers can happen when:

• you're going too fast for a curve in the road
• your loaded vehicle has poor stability
• the load shifts or moves within the vehicle.

Here's what you can do to reduce the risk of a rollover.

1. Reduce speed round curves

When you're going around a curve, even a small increase in your cornering speed results in a much larger increase in the outward sideways force which can tip your vehicle over.

What to do:

• when unladen, reduce your speed to that shown on the curve warning sign
• when laden, reduce your speed on curves to at least 10 km/h BELOW the posted speed shown.

NB At a roundabout or if you are turning at an intersection keep your speed low until both your truck and its trailer(s) have fully completed the turn and are straight behind each other on the exit road.

2. Don't overload your trailer

Look for a line on page 2 of your trailer's Certificate of Loading that looks like this:

Static roll threshold
0.35 g, 4.25 m/15 t, 18 t/3.70 m

This shows the height/weight load limits under the new Static Roll Threshold (SRT) and means that:

• if the trailer is loaded to its maximum height of 4.25 metres from the ground, the gross weight of its axles must not exceed 15 tonnes
• if the trailer is loaded to its maximum legal gross axle weight of 18 tonnes, then its maximum load height must not exceed 3.70 metres from the ground.

What to do: Make sure your load doesn't exceed the height or weight combinations shown on the Certificate of Loading or on a signed SRT Compliance Certificate (normally carried in the truck cab).*

* You may find that weights specified on the Certificate of Loading or SRT Compliance Certificate may be lower than the RUC licence weights or the maximum legal road weight for that vehicle.

3. Make sure your load is secure

Some loads are liable to move within the vehicle during the journey. You need to take extra care if your vehicle is carrying these types of loads:

• sheep, cattle, goats, deer, horses, etc
• hung meat carcasses
• bulk liquids in tanks.

What to do: Learn the right techniques to secure these loads, keep partially loaded compartments to a minimum and care.

REMEMBER

• Reduce your speed on curves by at least 10 km/h below the recommended speed shown on the yellow warning sign before the curve, particularly if laden. Don't speed up until all the vehicles in the combination have completed the turn.
• Ensure that your loaded trailer is within the maximum weight and height limits for SRT as shown on the Certificate of Loading or SRT Compliance Certificate.
• Make sure your load is properly secured (see the Truck Loading Code).

Need more information?

• SRT: see factsheet 13e Static roll thresholds
• checking your truck's SRT and safe loading levels [this can be checked on our online SRT calculator]
• load stability: see the Heavy vehicle stability guide (PDF, 157 KB).

For further details about safely securing loads to vehicles see the Truck Loading Code (available in bookshops).

Page created: 14 April 2005