WSP experts' thoughts on NZ's Safe Speed Programme

This month new speed limits for over 600 roads will come into force in Auckland and most central city speed limits will reduce from 50 to 30km/h in Wellington.  While improving safety outcomes is the key priority, speed reductions will deliver additional benefits for road-users and pedestrians. 

 

CS2020_598_2020SaferSpeeds-web01

Last year, 353 people died on our roads, making 2019 the forth deadliest year this decade. 

The Safer Speeds Programme (Safer Speeds) is New Zealand’s new approach to speed management. It fits within the Vision Zero methodology and aims to reduce the number of road deaths to zero.

Auckland Transport, says the programme will apply speed limit reductions to many roads in the Rodney and Franklin districts, in addition to 100 other roads across the Auckland region. Including the inner city. 

Speeds will reduce from 50 – 30 km/h on major CBD roads to improve driver, passenger, cyclist and pedestrian safety. 

WSP experts explore the positive impact the programme will have on our environment, economy and active transportation modes.

ENVIRONMENTAL GAINS

Rowan Dixon, Principal Specialist for Sustainability and Resilience is enthusiastic about the environmental gains that will come from improving Auckland’s speed limits.

“Lowering speed limits – especially in built up CBD areas – has environmental co-benefits.” 

“At 30 KM/h, traffic emits fewer greenhouse gasses and damaging pollutants, like NOx and particulate matter. This improves local air quality and can reduce our impact on climate change by reducing fossil fuel use by about 12%. This is generally because traffic flow in these areas is smoother with less braking and acceleration.” 

The impact of lower-speed limits on traffic flow was examined in a 2017 Barcelona study which found that drivers travelled seamlessly at a lower speed with small spacings while the network achieved a  relatively high and stable throughput.” 

Additional studies have found that aggressive driving at a slower speed limit still produces lower emissions (but higher fuel use) than non-aggressive driving at a higher speed limits (Newman and Kenworthy, 1992: 39-40).

A GERMAN STUDY FOUND THAT SMOOTH TRAFFIC REDUCES 

Gear Changing by
12 % 12 %
Fuel use by 
12 % 12 %
Brake use by
14 % 14 %
IDLE TIME BY
15 % 15 %
Newman & Kenworthy, 1992

ECONOMIC GAIN

Opposers of speed reductions believe it increases congestion and impacts on efficiency, with an associated economic cost. 

Fergus Tate , WSP Technical Director for Transport, is widely acknowledged to be one of New Zealand’s leading expert in road safety. He says reducing speed limits is the most cost-effective way to immediately reduce deaths and serious injuries resulting from traffic crashes.

A study commissioned by Waka Kotahi NZ Transport Agency tracked travel times along six different routes, looking at both longer journeys and shorter urban trips. It found that when driving at the maximum posted speed limit within the city wherever possible, drivers arrived at their destination as little as 1.08 minutes quicker than when they drove 10km/h slower.

Increasing safety may also improve journey times as well as reducing the physical and emotion harm caused by serious crashes and the additional economic costs and lost productivity from the resulting traffic jams while crashes are being investigated.

The Ministry of Transport estimates the value of statistical life (VOSL) is $4.37 million per fatality, 458,400 per serious injury and $24,700 per minor injury.

On a national scale the total social cost of motor vehicle injury crashes in 2017 was $4.8 billion. Loss of life/ life quality due to permanent impairments accounted for approximately 91% of this, vehicle damage accounted for around 5% and other costs made up the rest.

In 2017 there were a further 251,000 non-injury crashes, valued at $0.8 billion, making the total social cost of all motor vehicle crashes in 2017 at $5.6 billion, covering all injuries recorded by NZ Police, hospitals and ACC.

“The estimated economic (and social) cost of death and serious injuries in Auckland is $1.2 billion every year. We only have to save a few deaths and injuries on Auckland's roads, to more than recoup the implementation costs.” says Tate.

ACTIVE TRANSPORT GAINS

 Once rolled-out, the Safer Speed programme will create more opportunities for active transport in New Zealand. 

Risto Jounila, WSP Technical Director for Transport, has over 27 years in urban transport planning and has provided leadership on a variety of multi-modal transit orientated projects.

“There was a 128% increase in cyclist fatalities in 2019, with most happening in urban areas. Vehicle drivers are at fault for 87% of collisions and, as such, lowering speed limits in urban areas will create a much safer, less intimidating environment, for all,” he says. 

Several overseas studies show increased safety outcomes for cyclists as a result of vehicle speed reduction. Zein et al (1997) found a 40% reduction in the total number of crashes involving all modes of transport was achieved when calming traffic measures were introduced to Vancouver, Canada. 

The city of Graz in Austria was the first European city to introduce reduced speeds to 30 km/h on residential roads in 1992.  This resulted in a 24% reduction in accidents and a significant increase in walking and cycling. Less quantifiable but equally important was that residents also felt the livability of the city had been improved. 

Newer case studies can be found in two of Europe’s smaller capital cities; Helsinki and Oslo. 

Both cities saw a pedestrian fatality rate of zero in 2018 by reducing speed limits, redesigning streets and removing space for cars. Risto has been observing and planning Helsinki's traffic for most of his career and believes that although our cities still have a long way ahead in terms of developing traffic safety, the implementation of Safer Speeds gives the confidence that New Zealand is on the correct path.

“When pedestrians and users feel unsafe, the promotion of walking and cycling efforts are undermined. New Zealand made a statement last year when several active transport operators were pulled from our streets because they were deemed unsafe. It’s great to see the additional safety measurement taking place to ensure Aotearoa is equipped for the future of multi-modal transport.” 
 

Related Publications