Install traffic calming structures to reduce speeds

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

60%
Certainty

30%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Reducing the design speed of a road can be used to reduce vehicle speed rather than reducing the legal speed limit. Traffic calming methods include speed bumps, rumble strips, curb or pavement extensions (to reduce road width) and raised central medians/islands. Such structures get the attention of drivers and encourage them to slow down, which may help to reduce wildlife-vehicle collisions.

Study locations

Key messages

One study evaluated the effects on mammals of installing traffic calming structures to reduce speeds. This study was in Australia.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Abundance (1 study): A before-and-after study in Australia found that following installation of barriers to create a single lane, rumble strips, reflective wildlife signs, reflective wildlife deterrents, wildlife escape ramps and production of an educational pamphlet, a small population of eastern quoll population re-established in the area.
Survival (1 study): A before-and-after study in Australia found that following installation of barriers to create a single lane, rumble strips, reflective wildlife signs, reflective wildlife deterrents, wildlife escape ramps and production of an educational pamphlet, vehicle collisions with Tasmanian devils, but not eastern quolls decreased.

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A before-and-after study in 1990–1998 in Tasmania, Australia (Jones 2000) found that following installation of barriers to create a single lane, rumble strips, reflective wildlife signs, reflective wildlife deterrents, wildlife escape ramps and publication of an educational pamphlet, an eastern quoll Dasyurus viverrinus population partially re-established and vehicle collisions with Tasmanian devils Sarcophilus laniarius, but not eastern quolls, decreased. Results were not tested for statistical significance. Following local extinction, 3–4 quolls re-colonised within six months of installation, increasing to ≥8 animals after two years. Road-kills were similar for quolls before and after implementation (1.6 vs 1.5/year), but decreased for Tasmanian devils (3.6 vs 1.5/year). Vehicle speeds declined by 20 km/h (17–35% reduction) at the site centre and by 3–7% at edges. Following road widening in 1991, vehicle-wildlife collisions increased and quolls became locally extinct (from 19 animals). In 1996, four ‘slow points’ (barriers, creating a single give-way lane, rumble strips and four other interventions) were created. Animals were surveyed using 60 cage traps for three nights in alternate months in October 1990–April 1993. Then, 10–20 traps were set for 20–100 trap nights in each April, May and July of 1995–1998. Spotlight counts were made once or twice in 1991, 1995, 1996 and 1998. Road-kills were recorded in 1990–1996. Vehicle speeds were recorded at four locations.
Study and other actions tested
Referenced paper
Jones M.E. (2000) Road upgrade, road mortality and remedial measures: impacts on a population of eastern quolls and Tasmanian devils. Wildlife Research, 27, 289-296.

Please cite as:

Littlewood, N.A., Rocha, R., Smith, R.K., Martin, P.A., Lockhart, S.L., Schoonover, R.F., Wilman, E., Bladon, A.J., Sainsbury, K.A., Pimm S. and Sutherland, W.J. (2020) Terrestrial Mammal Conservation: Global Evidence for the Effects of Interventions for terrestrial mammals excluding bats and primates. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

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This Action forms part of the Action Synopsis:

Terrestrial Mammal Conservation

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Use chemical repellents along roads or railways Action Link	Unlikely to be beneficial	5	Synopsis Link
Modify vegetation along roads to reduce collisions with mammals by enhancing visibility for drivers Action Link	No evidence found (no assessment)	0	Synopsis Link
Install one-way gates or other structures to allow wildlife to leave roadways Action Link	Likely to be beneficial	7	Synopsis Link