A new Speed Management Guide released by the Government could see the speed limit increase to 110kph on some roads.
Associate Transport Minister Craig Foss said the Speed Management Guide combined a range of information to help all road controlling authorities decide where and when to make safety improvements or changes to speed limits.
He said changes made under the guide may include altering road design, lowering speed limits, or in certain circumstances, raising them. To be eligible for a 110 kph limit, a road would have to meet very strict conditions, including having a median barrier, at least two lanes in each direction, and no direct access to neighbouring properties.
Road Transport Forum chief executive Ken Shirley said the proposal to increase the speed limit would not apply to heavy vehicles.
“There is no proposal to increase the speed limit for heavy vehicles and generally we’re happy with the 90kph limit. What they are proposing is for the speed limit for lighter vehicles on set roads with lanes separated by barriers to be increased from 100kph to 110kph.”
Shirley said Static Roll Threshold was assessed on 90km/h and increasing the heavy vehicle speed by 10kph in line with the increase for lighter vehicles would significantly increase the risk of vehicle rollover.
“Even if you disregard safety for a moment, once a heavy vehicle is much above 90 km/h economic efficiency is greatly reduced anyway. Most operators know this.”
He said transport operators were keen to keep their drivers mindful of the 90kph limit and any increase to that could create problems.
“When there is only a 10kph difference in speed between heavy vehicles and other vehicles it is easy for operators to keep on top of this. If there were different speeds for different roads, then this would be difficult. There is also a concern that if the differential between vehicle types increased from 10kph to 20kph, there would be calls to confine heavy vehicles to the left lane.
“It is far more important to have a reliable steady cruise with minimal interruptions. The wider speed differential also provides motorists with safer passing opportunities and may lead to less frustration with heavy trucks on expressway routes.”
Foss said the Government was investing heavily to make the country’s roads safer, including spending more than $11 billion for seven roads of national significance and $212 million for 13 important regional road projects.
“We have also significantly increased our investment in road safety, with about $550 million more in the National Land Transport Programme than three years ago,” said Foss.
The Speed Management Guide will replace the speed setting guidance in the Land Transport Rule: Setting of Speed Limits 2003. Consultation on the changes will begin in early 2017.