As speed bumps gain traction in Hamilton, an expert says the safety benefits of traffic-calming devices outweigh any public backlash.
By Jordan Smith, Local Democracy Reporter
The analysis comes as Waipā District Council reviews 12 raised safety platforms (RSPs) following concerns about how they are performing. The council estimates fixing each platform would cost between $8000 and $10,000.
Speed platforms and other traffic-calming measures have been a feature of Hamilton’s roads for several decades, according to the city council’s infrastructure and asset general manager, Kevin Strongman.
RSPs typically used today were introduced around 2013, Strongman added, saying council initially drew guidance from Australia and the Netherlands until adequate local experience was gained.
“Council considers factors such as vehicle speeds, crash history, traffic volumes and the mix of road users in the area, including people walking, cycling and crossing the road.
“RSPs (speed bumps) are used in locations where lower speeds can help reduce the risk of death or serious injury if a crash occurs.”
Strongman referred to studies evaluating the effectiveness of speed bumps released by NZTA.
Standout statistics included speed bumps at existing intersections/roundabouts cutting fatal and serious crash risk by 40%, and a 50% reduction in injury crashes with the use of elevated stop lines at traffic signals.
Engineering New Zealand Transport Group immediate past chair John Lieswyn said speed bumps and RSPs in general have been in New Zealand and Australia’s official road transport safety guidelines "for decades".
The main goal of the devices was to bring motorists’ speeds down, particularly when a mistake was made on the road, through “vertical deflection”, Lieswyn said.
He said there had also been a greater national focus in recent years on installing the devices to address gaps in traffic law enforcement.
“In other countries, if you fail to give way to a pedestrian at a zebra crossing you'll eventually get a ticket, and it'll be a big one. We don't do that so we have to use engineering measures to ensure pedestrian safety."
Lieswyn said media coverage had highlighted a backlash against vertical deflection devices, despite “strong” evidence they improve road safety.
He said problems typically arose when the devices were installed in unsuitable locations, such as main arterial roads.
He added councils will often install devices after complaints of speeding drivers and the public feeling unsafe.
"Go speak to the people who asked for it and they're going to be saying 'thank you council for putting it in'. We're not hearing that because the news media would prefer to talk about the person with their arms folded and the frown on their face outside one of these devices, right?
“If you create the driver expectation that route is 30km/h because it's adjacent to schools or a mall where you have a lot of vulnerable pedestrians, the driver expectation is 'I should be going slower here' and then you don't have as much of a problem with backlash."
Queried if emergency services are negatively affected by the devices, Lieswyn emphasised installation leads to less road trauma, therefore reducing a need for emergency services “in the first place”.
He referenced a coastal North Island fire department initially fearing RSPs would significantly increase emergency response times.
However, the fire department's model assumed vehicles travelled at a constant 50km/h and failed to account for turns and stops.
"They said 'people are going to die and houses are going to burn because we can't get across town'... a more accurate model showed it wasn't much of a difference."
LDR is local body journalism co-funded by RNZ and NZ On Air
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