Whangārei getting ‘fair share’ of additional wombat crossings - John Williamson

An example of a raised pedestrian crossing. Photo / Wellington City Council

OPINION

On September 11, 2002, the World Trade Center in New York was obliterated by terrorists flying jumbo jets. The aftermath precipitated retaliatory wars in Iraq and Afghanistan.

Controversial incursions based on the premise that Iraq harboured weapons of mass destruction, which warranted an allied invasion. As a justification for this, US Secretary of Defence Donald Rumsfeld waxed poetic in a now famous summary of the issues facing decision-makers in assessing risk and uncertainty.

Rumsfeld said, “Reports that say something hasn’t happened are always interesting to me because, as we know there are some known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns - the ones we don’t know, we don’t know.”

Popular commentary since suggests that Rumsfeld missed one - the unknown knowns, the things that we know without knowing that we know them. Together they form a decision matrix called the Johari Window - a popular tool for decision-makers to assess a roading project or a potential country invasion.

This is raised in the context of a move from a prescribed approach for temporary traffic management to a risk-based approach, and what factors might fall into the known/unknown categories in assessing the risks of a road job.

But this column isn’t just about temporary traffic management. It’s also about the apparent war of words going on in relation to the proliferation of raised pedestrian crossings and speed bumps that are a big focus of road controlling authorities right now.

The difference in view is characterised by public statements from the Browns - Auckland Mayor Wayne Brown and Minister of Transport Simeon Brown. The minister stated, “Not only are they a significant cost, but the significant number of these raised platforms that have been installed, particularly on busy roads, simply increase travel times and reduce the productivity of the network.”

The politicians are talking about the fully engineered wombat raised crossings, against the conventional painted zebra pedestrian crossings.

Whangārei is getting its fair share of these additions to our roads. A drive through Kamo’s walkability environment will attest to big money being spent, with questions being raised of the costs against the benefits.

The problem being addressed is pedestrian safety and speed through these areas. There is clear evidence of an issue and how these devices are effective there. An Australian study published in 2017 indicated a reduction of 63 per cent in pedestrian casualties where wombats are installed.

While an Israeli study published in the same year involving video recording and free flow speed measurement reported, ”A substantial decrease was observed in vehicle travel speeds when approaching the crosswalks, which was maintained over time. Improvements were found in the rates of giving way to pedestrians by vehicles, vehicle-pedestrian conflicts, and numbers of pedestrians who cross within the crosswalk boundaries, while the changes in keeping to safe crossing rules were mixed.”

There’s no question that these things work in terms of slowing vehicles down and keeping pedestrians safe - so long as the pedestrians behave. But the question of cost and disruption, as well as possible vehicle damage and neighbour noise, are unknowns when it comes to building them, as opposed to just painting a crossing.

The cost can vary. A recent project at Kumeū where precast units were used cost ratepayers $35,000. The precast unit was installed overnight with minimal disruption and traffic management cost, as well as health and safety and emission benefits. Potential weather disruption was mitigated with under cover construction of the unit.

This is about 10 per cent of reported cost of other crossings where there could be associated works of stormwater improvements, catch pit upgrades, pedestrian approaches, footpath and bus stop upgrades as well as street lighting, all of which could be needed for safe pedestrian access and flood mitigation. It’s not just a lick of paint as Mayor Brown insinuated.

As Donald Rumsfeld suggested, there are knowns and unknowns, some you know about and others you don’t. Cost can be an issue but the speed reduction and pedestrian safety benefits are obvious.