Final report: Testing the effectiveness of turtle crossing signs as a conservation measure

  • Published source details Johnson G. (2012) Final report: Testing the effectiveness of turtle crossing signs as a conservation measure. SUNY Potsdam report, for St. Lawrence River Research and Educational Fund, New York Power Authority, New York, USA.


This study is summarised as evidence for the following.

Action Category

Use signage to warn motorists about wildlife presence

Action Link
Reptile Conservation
  1. Use signage to warn motorists about wildlife presence

    A replicated, controlled, before-and-after study in 2008–2010 on 18 roads through swamps and wetlands in New York, USA (Johnson 2012) found that road signs did not decrease painted Chrysemys picta and Blanding’s Emydoidea blandingii turtle road mortality. The percentage of turtles encountered that were dead was similar on roads with signs (2009: 49 of 72, 68%; 2010: 20 of 31, 65%) and roads without signs (2008: 40 of 71, 56%; 2009: 28 of 53, 53%; 2010: 16 of 28, 57%). Road signs warning drivers of turtles were installed during the nesting season (1 June–1 July) on five roads in 2009 and nine roads in 2010. Driving (daily) and walking (100 m transect, 1–2 times/week) surveys were conducted to count the number of turtles encountered (dead and alive) before signs were installed in 2008 (9 roads) and after signs were installed in 2009 (Signs: 5 roads; no signs: 5 roads) and 2010 (Signs: 9 roads; no signs: 9 roads). Dead animals were removed to prevent double counting. Results from 2010 include only driving surveys.

    (Summarised by: Maggie Watson, William Morgan)

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