Log Truck Loads To Be Longer, Lower, Safer
31 May 2002
Logging trucks are to be allowed to carry slightly longer and significantly lower loads, to reduce rollover crashes which have plagued the industry for years, Acting Transport Minister Judith Tizard said today.
Ms Tizard said an independent report on road trials concluded that rollover crashes involving log trucks could be reduced by up to 40 percent if all high-loaded log trucks were allowed to operate with the lower and longer loads.
“New Zealand motorists will be safer with the lower logging trucks on the road. Computer modeling, two separate on-road trials and a series of handling tests of the vehicles all found major improvements in vehicle stability as a result of the re-configured loads.
"Once you've actually seen a truck with the lower load it becomes very obvious why they are safer. We're talking about vehicles with a much lower centre of gravity, which are much more stable and much less likely to roll over. That's good for road safety.”
On average it takes about a half second longer to overtake a 22 metre logging truck, a drawback that Ms Tizard said was far outweighed by the safety benefits of the lower and more stable loads.
The longer and lower logging trucks will operate on the country's roads from June 20, when the Land Transport Safety Authority (LTSA) will issue a gazette notice approving their operation. All trucks operating at 22 metres will display extra lights, signs and flags, including high visibility panels on the rear of the load at night.
The reconfigured vehicles will have their trailer load heights dropped from 3.8 metres to between 2.0 and 2.6 metres on average, with a maximum height of 3.2 metres. The height reduction is achieved by splitting one packet of logs into two smaller packets loaded end-to-end, resulting in up to a two metre increase in overall vehicle length (to 22 metres) with no increase in weight.
For further technical information see the LTSA website, www.ltsa.govt.nz.
Questions and Answers - 22m logging trucks
Q: Why are you allowing log trucks to
A: The trucks themselves are not any bigger, the loads they carry are just configured differently. No extra logs are being carried and there is zero increase in weight. Trials have shown that the new loading method could cut log truck rollover crashes by up to 40 percent. We have a responsibility to see that New Zealand drivers benefit from these safety improvements.
Q: How big of a problem are log truck rollovers?
A: Over 2/3 of all log truck crashes result in a rollover. These crashes can be very dangerous, with heavy logs spilled onto the road and into the path of other traffic. On average, about more than one logging truck rolls over every week in New Zealand. There were 60 on-road rollover incidents in 68 million km travelled in 2001.
Q: Aren't you just bowing to demands by the logging industry to carry bigger loads?
A: No - the loads are not any bigger, they are just configured differently. No extra logs are being carried and there is zero increase in weight. The industry has proposed that these longer and lower loads be allowed because it is in their interests to stop their trucks from rolling over and losing loads.
Q: Whose idea was it to lower and lengthen the loads on log trucks?
A: In order to reduce the rollover rate of logging trucks the logging industry (through the Log Transport Safety Council, requested that the LTSA permit existing logging truck-trailer combinations to operate at 22m overall length when laden. This was considered the most promising way of improving stability out of options including reducing truck speeds in corners, building lower trailers, discouraging drivers from travelling on the road shoulder to let other motorists past, and extra enforcement.
Q: Why do the loads have to be two metres longer - why can't they just be lower?
A: We want to maintain the existing payload of logs carried on trailers - otherwise extra journeys and more trucks on the road would be required. This is achieved by taking a single high packet of logs and redistributing them into two low bundles one behind the other. The height is substantially reduced with a two-packet load and load length is only marginally increased.
Q: Aren't you
circumventing the Vehicle Dimensions and Mass Rule by
allowing trucks to operate at lengths of 22m, when the
maximum in the rule is 20m?
A: No. It needs to be remembered that the vehicles are not actually any longer, just the loads. The 22m logging trucks are much shorter than vehicles already on our roads every day, operating under overdimension permits (e.g. moving cranes, houses, heavy machinery). These frequently reach 25m in length, and can extend up to 35m.
Q: How many logging trucks were involved in the trial?
A: The initial trial involved seven trucks are operating on roads in Northland, the East Coast, and the central North Island. The main two routes were between Mount Maunganui and Kawerau, and Mount Maunganui and Kinleith (Tokoroa). The second trial involved 20 trucks operating in these areas as well as in Christchurch, Timaru and Nelson.
Q: How many logging trucks are we likely to see operating at 22m?
A: About 300 to 400 logging trucks will be able to operate at 22 metres. The remaining majority will be reserved for carting the single-packet log loads that are already done within a low and stable height.
Q: What were the results of the trials?
A: Transport Engineering Research NZ (TERNZ) have prepared a report analysing the technical and safety issues in this trial. The safety benefits likely to be gained from allowing these vehicles to operate at 22 metres overall length when laden appear significant. Notably, if the maximum of 70 percent of ‘difficult’ logs were transported using the 22 metre approval on multi-bunk trailers, the reduction in on-highway rollover crashes could be up to 30-40 percent if the same vehicle kilometres were travelled. A slight increase in risk from the length increase can be managed by additional operating conditions such as signage and lighting.