Our road toll is too high and over the last 12 months 330 people died on our roads. While absolutely that number is an improvement compared to decades ago, it is an increase on recent years with three years ago it reaching a low of 249. As a comparison, per capita Sweden has less than half the number of road deaths that we do.
Here’s our road toll over the last decade showing it having increased. If we had Sweden’s level of road deaths we’d have only 137 per year. The Ministry of Transport say that in 2015, speed was a contributing factor in 101 deaths, 496 serious injuries, and 1,831 minor injuries.
Yesterday the government announced a new Speed Management Guide which the Ministry say will modernise how speed limits are set. It includes the ability to raise speed limits on some selected roads to 110km/h, which the media have latched on to, but also allows for speed limits to be lowered easier too. That’s good as it means once implemented could make it much easier to have lower speed limits in urban areas – I understand the process currently for doing so is fairly laborious.
The ministry say the current methodology for setting speed limits dates to the 60’s and narrowly focuses on speed limits. The new guide breaks down roads into one of four key classifications
- High Volume
- National, Regional, Arterial
- Primary Collector, Secondary Collector
- Access/Low volume access
Examples of these for urban and rural areas are below and includes information on modes and volumes that could be expected in situations.
The guide says
The Framework sets out safe and appropriate speed ranges taking into account road function, design, safety and use. The ONRC has been through a moderation process, but will still be sense tested through the speed management lens as an Important input to determining the safe and appropriate speeds on the network. This Guide steers RCAs to where the highest benefit opportunities lie on their networks. It should begin to underpin all speed management activity, such as engineering and investment decisions, land use planning, fleet management, communication and enforcement. It will also progressively become embedded into planning, engineering and network management.
With these in mind, the proposed safe and appropriate speeds for different types of road fall within the ranges shown in Figure 1.4. The proposed speed ranges are not in themselves speed limits, and no changes to the default limits are proposed. Risk can be reduced by investing In infrastructure improvements to make a road safer at current speeds, or by managing speeds down through a combination of road design, risk targeted enforcement and safe behaviour, all reinforced by the speed limit appropriate for the road.
And below are the proposed speed ranges. The guide does say these aren’t limits and no changes to the current default limits are planned.
The various classification tools used to determine speeds are meant to be to ensure speeds are set appropriately for the conditions. Below is a table listing different urban road types along with various risk ratings and just what the proposed speed might be.
There are a couple of concerns I have with this approach. Reading the document, while I’m sure better than what we have now, still feels very engineering driven. In some ways it is pick the speed limit you want and then design the road to meet that. In urban areas that could have big consequences the amount of land needed for some roads. I also wonder if some cases if we could see agencies push to ‘Engineer Up’, upgrading roads at often great expense, rather than just lowering speeds to appropriate levels.
And what impact this will have on overall economic evaluations as travel time savings usually play a large role in the justification for projects – although to achieve the travel time savings for some projects, such as Puhoi to Warkworth, you’d have to be driving much faster than even the new proposed 110km/h limit.
As mentioned earlier, there are only a few places were the proposed new upper speed limit would be in place. The NZTA say just 155km of road, subject to minor changes, meet the criteria, although they’re currently assessing another 222km out of a possible 425km to see what work would be needed. The 155km proposed are:
- Auckland Motorway network:
- Johnston’s Hill Tunnel to Lonely Track section of the Northern Motorway (SH1)
- Upper Harbour Motorway (SH18)
- Takanini to Bombay section of the Southern Motorway (SH1).
- Waikato Expressway (SH1):
- Cambridge, Rangiriri, Ohinewai, Ngaruawahia and Te Rapa sections
- Longswamp section of the Waikato Expressway — when completed in 2018
- Huntly and Hamilton sections of the Waikato Expressway — when completed by 2019.
- Tauranga Eastern Link (SH2).
They also say other sections likely to be eligible for a 110km/h limit are
- Kapiti Expressway, SH1
- Transmission Gully, SH1
- Northern section of Christchurch Motorway, SH1.
Overall I don’t have too much problem with the proposal. The increased 110km/h limit is being confined to only a handful of locations but the changes proposed also provides the opportunity for more sensible speed limits in many of our urban areas.