NZTA turns myth buster in battle to cut speed limits

Sunday, 20 October 2019

NZTA wants to reduce the 100kmh sections on State Highway 6, between Blenheim and Nelson, to 80kmh.

High speed is the major factor for serious roadside accidents, the agency says.

Stuff has spoken to local businesses, primary schools, residents, and truck drivers, and they all share the same view - opposing NZTA.

People against the idea have argued slower speeds will hurt the economy or cause more crashes, or that the road needs fixed, not the speed limits, or that crashes are just down to bad drivers.

**READ MORE:

* Slower speeds outside schools, not the whole highway, say principals

* Highway speed limit near Nelson will drop

* Lower speed limits made permanent along parts of State Highway 1**

In chasing more info from NZTA, Stuff was directed to the agency's 'myth busting' link online.

Here's some of the myths around speed as per NZTA's research.

Myth: Lower speed limits will harm the economy, especially for moving freight

A research project commissioned by the NZTA found a drop in maximum speed travelled along certain routes from 100kmh to 80kmh increased travel times by around 10 per cent and reduced fuel use by about 15 per cent.

So while there would be small increases in travel times with lower speed limits, these pale into insignificance when compared with the potential to save lives and prevent serious injuries.

An earlier NZTA unpublished report studied the combined impacts of changes in mean speeds to road safety risk, travel times and fuel use for heavy vehicles. It concluded that the 'optimum' speed for heavy vehicles taking these three factors into account would be around 80kmh (Max Cameron, 2012)

Myth: Modern cars are safer and better, so there's no need for us to drive slower

Cars may have evolved to go faster, but humans haven't; our bodies feel the force of a crash the same way they did when the first car was invented.

While modern cars have better safety equipment that can help protect us, half the cars on New Zealand's road lack even basic safety features, like electronic stability control or side airbags.

New Zealand roads are often unforgiving and leave no room for error. Many do not have median barriers to prevent head-on crashes, or roadside protection to stop people hitting trees and power poles.

Even the best technology won't stop another vehicle crashing into you or protect you from impact with a roadside object.

Myth: It's slow drivers who cause crashes, because they cause others to overtake

Travelling too fast for the conditions contributed to the cause of about a third of all fatal crashes. On the other hand, slow driving is not significantly implicated as a cause in our poor crash statistics.

The posted speed limit is a maximum not a target. Drivers are expected to adjust their travelling speeds depending on the weather conditions and road environment and show patience.

Myth: The speed limits in NZ are low compared to other countries, so it's ridiculous to make them even lower

Our roads are unique. They are windy, hilly and often single lane so can be challenging and demanding to drive, and the consequences of small errors can be fatal. And yet we have a default speed limit of 100kmh on most open roads, regardless of how safe they might be to drive.

Many countries we compare ourselves with have a default speed limit on the open road that is lower than ours. It's only on highest quality motorways in some of those countries that speed limits are higher.

We need to help drivers choose the right speed for the road. We also need to reduce the risk on the road by improving the roads or lowering speed limits.

Myth: The problem isn't speeding – it's bad drivers 

Improving everyone's driving skills, and their ability to read the road, would have a positive impact on the speeds people travel and the harm done on our roads. Speed is one risk that good drivers can minimise.

In fact, it has been found that: if all road users complied totally with all road rules, fatalities would fall by around 50 per cent and injuries by 30 per cent, therefore around 50 per cent of fatalities and 70 per cent of injuries would remain (Elvik R, 1997.)

Myth: It's the road not the speed limit that needs changing

New Zealand's roads are not as safe as those in other countries. Our road network is comparatively long and stringy and much of it was built when vehicles travelled at much lower speeds. 

Engineering improvements such as median barriers are proven, effective and long-lasting, but they are not cheap. The new road safety strategy currently under development will seek a much greater level of ambition, including investment in roading improvements, but it is going to take time to make all our busiest, highest risk roads safer.

It will not be economic to invest in improvements to all our risky roads to make them safer at their current speed limit, so we need to consider other solutions too. This includes lowering speed limits where investment cannot be justified, increased enforcement and encouragement of safe road use.

Myth: Introducing a lower speed limit on its own won't change traffic speeds

The evidence is very consistent that, for every 10kmh posted speed limit reduction, typically you observe a 2 to 3kmh reduction in mean or average speeds, all other things being equal. That might not seem much, but again research has found that every 1 per cent reduction in speed generally results in a 4 per cent reduction in fatalities (The World Health Organisation). So even a 2 to 3kmh drop in an urban area could mean 8 to 12 per cent fewer fatalities.

Myth: Slowing down will mean it takes a lot longer to get anywhere

Many people over-estimate the time they would lose if they drove at a slower speed.

A study, commissioned by NZTA, tracked travel times along six different routes spread between several major towns and cities and looked at both long journeys and shorter urban trips. It found that when driving at the maximum posted speed limit wherever possible, drivers saved as little as 1.08 minutes than when they drove 10kmh slower.

Trips reducing the maximum speed from 100kmh to 80kmh on a 10km length of road showed travel time increases ranged from 30 to 48 seconds. For local trips reducing the maximum speed from 50kmh to 40kmh showed travel time increases ranged from 11 to 42 seconds difference.

Myth: Going a few kilometres faster or slower doesn't make any difference to safety

When a vehicle crashes, it undergoes a rapid change of speed, but the people in the vehicle keep moving at the vehicle's previous speed until stopped.

The faster the speed at which the human body must absorb the energy released in the crash, the greater the severity of the resulting injury.

Your speed dictates what happens if you hit another vehicle or person and whether you have time to react and avoid a collision. For example, if someone steps out in front of you and you take one second to react:

Driving at 50kmh, you need at least 27m to stop.

Driving at 60kmh, you need at least 36m to stop.

Myth: Speed isn't a major cause of road crashes

According to police reports, travelling too fast for the conditions was a contributing factor in about a third of all fatal crashes, and it affects the impact of every crash.

Even good drivers make mistakes sometimes. Speeding is one risk that good drivers can minimise, it contributes to the severity of the impact.

For car occupants in a crash with an impact speed of 80kmh, the likelihood of death is 20 times what it would have been at an impact speed of 40kmh.

According to MegaMaps analysis, half of all injury crashes occurred on roads and streets where the speed limit was higher than the recommended safe and appropriate speed.