Predictable speed cameras reduce benefits, says auditor


Mobile speed cameras create a general deterrent to speeding, as drivers don’t know where they could be at any time, making cars will slow down and saving lives.

That’s how it’s meant to work, anyway.

But there is “limited evidence” this is happening with New South Wales’ mobile speed camera system, says NSW Auditor General Margaret Crawford.

This is because the way it operates “makes enforcement more predictable, reducing the ability to provide a general deterrence”.

It does this by operating in a limited number of areas to a regular schedule, and providing clear signage as drivers approach a camera.

These practices “have reduced the broad deterrence of speeding across the general network — the main policy objective of the mobile speed camera program,” says Crawford.

“Key aspects of the state’s mobile speed camera program need to be improved to maximise road safety benefits.”

Fatalities starting to increase

There is evidence of a reduction in fatal and serious crashes at the 30 best-performing mobile speed camera locations, and compliance with speed limits has improved at the sites and locations that mobile speed cameras operate.

But this does not appear to be translating through to the rest of the state’s roads.

“A previous study in Queensland found higher levels of randomness in the selection of speed camera sites for operation were associated with greater crash reductions.”

“There is limited evidence that the program in New South Wales has led to a behavioural change in drivers by creating a general network deterrence,” Crawford states.

And while the overall reduction in serious injuries on roads has continued, fatalities have started to climb again.

The use of signage appears to be quite effective at alerting drivers to where cameras are (and, conversely, where they are not). Prior to the release of the Speed Camera Strategy in 2012, signs were posted 50m before a camera; now drivers are notified 250m in advance.

Not only does this tip people off, it has also reduced the number of places cameras can be used and increases the time needed to set them up. It has made it more difficult to deploy cameras in school zones, for example, where surveys indicate fewer than half of drivers comply with 40km/h speed limits.

There is a current lack of suitable sites for using cameras, but deployment has nonetheless been weighted towards only a certain proportion of eligible sites, further reducing randomness. A previous study in Queensland found higher levels of randomness in the selection of speed camera sites for operation were associated with greater crash reductions.

In addition, the locations most often visited are often not those at highest risk of speed-induced crashes, leading the auditor to conclude the “scheduling system is not prioritising locations well”.

“NSW uses speed cameras less than other states. Even after significantly boosting the number of hours cameras are on the road, NSW is still far behind Victoria and Queensland.”

And NSW uses speed cameras less than other states. Even after significantly boosting the number of hours cameras are on the road, NSW is still far behind Victoria and Queensland.

“No analysis was undertaken to estimate the MSC [mobile speed camera] hours required to achieve the program purpose of a general network deterrence to speeding,” says the audit.

In Transport for NSW’s response to the audit, Secretary Rodd Staples said he welcomed the opportunity the audit provides to improve the system.

The agency agreed to implement the auditor’s recommendations to review the system and its key performance indicators “in the context of policy settings”.

The number of hours of camera deployment and signage requirements would not be reviewed, however, “as these are existing government policy settings”.

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