70kmh rural road speed limit advised
WELLINGTON: A new report recommending 70kmh speed limits on rural roads has been dismissed by the New Zealand Automobile Association.
The report by the 59nation International Transport Forum (ITF) recommends a 70kmh speed limit on all rural roads, including state highways, without a median barrier.
It also proposes reducing speed limits to 30kmh in urban areas where cars share space with cyclists and other ‘‘vulnerable road users’’, or 50kmh in other urban areas.
Automobile Association spokesman Dylan Thomsen said 87% of AA members in 20 surveys over the past five years opposed reducing the openroad speed limit to 90kmh.
The ITF report says every 1% increase in average speed increases road deaths by 4%.
‘‘Thus reducing speed by a few kmh can greatly reduce the risk and severity of crashes,’’ it said.
‘‘Lower driving speeds also benefit quality of life, especially in urban areas as the reduction of speed mitigates air pollution, greenhouse gas emissions, fuel consumption and noise.’’
The report is based on analysing the effects of changes in speed limits or introducing automated speed enforcement in 10 countries since 1993.
For example, Sweden cut deaths by 41% on rural twolane roads with inadequate road shoulders by reducing the speed limit from 90kmh to 80kmh in 2008.
At the same time, it raised the speed limit on some motorways with high safety standards from 110kmh to 120kmh, with no significant change in road deaths.
New South Wales cut road deaths in urban areas by 45% by lowering the urban speed limit from 60kmh to 50kmh in the late 1990s.
Italy cut crashes on the A56 urban motorway network by 32% by installing 320 cameras along the 2900km network, allowing police to calculate cars’ average speeds between the cameras.
‘‘Speed limits should be set based on the Safe System principles and taking into account the function and use of the roads,’’ the report concludes.
The aim of a Safe System is to offer a road system that can accommodate the unavoidable human error without leading to death or serious injury. This means that the forces a human body can tolerate and still survive must be considered when designing the road system and setting the speed limits.
‘‘Such physical limitations are, for example, that most unprotected road users survive if hit by a vehicle at up to 30kmh, a modern car can protect occupants up to 50kmh in a side collision and a safe car can protect occupants up to 70kmh in a headon collision.
‘‘In urban areas, where there is a mix of motorised and nonmotorised road users sharing the same space, speed limits above 50kmh are not acceptable.
‘‘In areas with a high density of vulnerable road users, a limit of 30kmh is to be preferred.’’
In New Zealand, Mr Thomsen said speed limits were set by an agreed speedmanagement guide requiring councils to identify the top 5% and 10% of roads in their districts with the highest crash risks, or with the biggest discrepancy between the current speed limit and actual average traffic speeds.
For example, the Waikato District Council reduced speed limits on many rural roads on Monday.
Rotorua Lakes Council is proposing new speed limits on several local roads including Hamurana Rd along the northern edge of Lake Rotorua.
‘‘They [councils] have the capability now to look at setting those speed limits, but there are guidelines and regulations they have to comply with,’’ Mr Thomsen said.
But he said 87% of AA members in recent surveys opposed a blanket reduction in the openroad speed limit to 90kmh, and 80% opposed lowering the speed limit in urban areas to 40kmh. — NZME