Will reducing the speed limit from 100 kilometers per hour to 80 slow traveling time that much?
Just four to six minutes, says New Zealand transport expert Paul Durdin in an 81.4-kilometer windy highway in the county’s famous holiday highway from Christchurch city to Akaroa. The result he finds through modeling and from his actual drive.
Stuff reports on the benefits of reducing the speed limits on some highways in the country and shares the finding of the study commissioned by the NZ Transport Agency Waka Kotahi.
The move to reduce the speed limits can cause great concern for drivers, particularly its potential to slow down traveling time.
As Durdin pointed out, modeling shows that in an 81 km highway, reducing the speed limits from 100 to 80 kph can only add 6 minutes to travel time in an 80 kilometer.
The advantages of lowering the speed can outweigh the extra distance in New Zealand’s largest city, causing the approval of the speed limit changes for more than 1600 roads.
However, all over the country, at least 76,000 km – or 80% of its 95,000km – of road have an inappropriate speed for the road type, says Durdin.
Benefits of reducing speed limits
As a result of lowering the speed limit, the extra minutes mean that drivers are far less likely to be in a serious or deadly crash.
Durdin shared that Last year, 320 people died on the roads. Another 2800 are seriously injured on average each year. Sadly, it is not always the at-fault party who suffers an injury but other drivers and vehicles impacted by that driver.
Lower speed limits can give more time for drivers to correct or evade any potentially fatal errors.
At 80kph, their vehicle is near peak efficiency, Durdin said, meaning the new speed reduces the fuel consumed – saving emissions and reducing petrol bills. “Fuel efficiency significantly improves, compared to traveling at 100 or faster”, Durdin says.
New Zealand Transport Agency (NZTA) Waka Kotahi commissioned a study, “Economic Analysis of Optimum Speeds on Rural State Highways in New Zealand,” to “calculate the optimum speeds for light and heavy vehicles, balancing out journey time, fuel costs, safety, and environmental emissions.”
University professor Max Cameron, the study’s author, “found the benefits of fewer accidents, lower carbon emissions, and smaller bills outweighed the economic costs of people spending some extra time on the road.”
Study findings show that cars can travel at 105 kph for divided four-lane motorways, but trucks should remain at 80 kph.
The car’s optimum speed is 70-85 kph on all other roads.
As with trucks driving on the motorways, their optimum speed is at 70kph.
“Trucks are much more likely to produce fatal and serious injury crashes – and release a lot of air pollution,” Max Cameron says.
Cameron’s modeling revealed that following these appropriate speeds would prevent around 1500 – from a yearly total of about 8700 down to 7200. It will also cut carbon emissions by more than 500,000 tonnes per year.
Cars will consume less fuel, saving the country $414 million yearly or 6% on vehicle operating costs. The only trade-off to this is an increase in travel time by 10.5%.
Durdin says that transport planners do not often emphasize the benefits of lower speeds, but the concept is gaining more traction in urban areas.
“Communities are actively pushing for lower speed limits in their areas because they want to create safer environments where they can have their children walk, bike or scoot to school.”Paul Durdin
Cameron hopes that the benefits of reducing speed limits could win over the public.
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