Koala smiley signs slow down drivers

22 Aug 2019


The Gold Coast supports an important population of koalas and is part of South East Queensland’s koala coast. The koala coast population has been steadily declining for a range of reasons, with vehicle-strikes being of particular significance.

Currently, wildlife warning signs are one of the only wildlife-vehicle collision mitigation measures that can be implemented quickly, for relatively low cost and at the landscape scale. Although static wildlife warning signs are the most common and widespread form of collision mitigation, evidence of their effectiveness is inconsistent. Recent innovations in traffic signage could potentially reduce the risk of wildlife-vehicle strikes and assessing their impact and optimising their designs and messages is important.

In 2018 the City, in partnership with the Griffith University Road Ecology Group and Redland City Council, undertook a 10-week pilot research project to evaluate how effective different types of dynamic road sign messages were at reducing vehicle speeds in known koala areas.

The signs used for the trial were Speed Awareness Device (SAD) signs, with standard fluorescent yellow panels and the wording ‘KOALA ZONE’ above a standard yellow warning sign displaying a black koala silhouette. The signs have a built in speed detection radar and display variable images depending on the speed detected. Each sign recorded the date, time, and two speeds: one when the vehicle was first detected and one when the vehicle passed the sign. Control data for each site was collected prior to the signs being installed.

On the Gold Coast, four signage locations were selected along two roads known for koala vehicle strikes: Discovery Drive in Helensvale and Pine Ridge Road in Coombabah/Runaway Bay. Two message types were displayed:

  • The ‘smiley message’ displayed a green smiling face image at low speeds, a yellow smiling face image with ‘BE ALERT’ at medium speeds and a red sad face image with ‘SLOW!’ at high speeds.
  • The ‘thank you message’ displayed the text ‘THANK YOU’ in green at low speeds, ‘STAY ALERT’ in yellow at medium speeds and ‘SLOW DOWN’ in red at high speeds.

All signs were programmed to alternate the relevant message with the speed of the vehicle, with the colour of the speed number matching the respective messages.

Outcomes of trial

  • At all sites, both the smiley message and thank you message reduced average vehicle speed and the proportion of vehicles speeding (which equated to thousands of vehicles).
  • Differences in the driver behaviour between the two sign messages were negligible. However, the smiley message consistently performed slightly better across the sites at reducing driver speed.
  • Compared with the control period, average speed and the percentage of vehicles speeding were reduced following installation of the signs at all sites, except site 4 (Pine Ridge Rd South). It is possible that an unknown and unforeseen event at this site disrupted usual traffic patterns during the control period and resulted in unusually low vehicle speeds being recorded.
  • Vehicle speed tended to reduce more at night, with excessive speeders reducing their speed more than both non-speeders and moderate speeders.

A special thanks goes to Division 4 Councillor Kristyn Boulton who purchased the two signs that were deployed along Pine Ridge Road, as well as the subsequent WILDLIFE road paintings. The signs on Discovery Drive were funded by the City’s Vulnerable Species Management Team.

You can download the full report here

Division 4 Councillor Kristyn Boulton

Division 4 Councillor Kristyn Boulton with a Koala SAD sign

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