#28 Speed Feedback Signs

Speed feedback signs (SFS) are electronic radar-equipped signs that detect approaching vehicle speeds and communicate information back to drivers about their speed limit compliance. As a form of Variable message sign (VMS), SFS information can be customised according to specific needs and objectives, but typically includes one or more of the following displays (potentially in combination):

• Vehicle speed as measured

• Green smiling face graphic for compliant speed

• “THANK YOU” text for compliant speed

• Red frowning face graphic for non-compliant speed

• “SLOW DOWN” text for non-compliant speed

  
  

As a speed management measure, SFS can potentially be found on all road types, but are most common in low-speed areas such as school zones, roadwork zones and high-volume pedestrian locations. Having been used increasingly over recent decades in Australia and internationally, SFS are also variously known as Speed monitoring displays (SMD), Dynamic speed display signs (DSDS), Driver feedback signs (DFS), and Vehicle-activated signs (VAS).

Speed feedback signs at Queen Vic Market, Melbourne

Source: Gary Commane, Vivacity

Effectiveness

SFS have proven effective for improving speed limit compliance in a range of different contexts, including school zones, work zones and the general road network. According to published evaluations, the degree of effectiveness is influenced by many factors other than the SFS itself, and the potential for “novelty” effects is noted, although effects tend to be largely sustained long-term. Examples from a selection of international case studies include:

• Combination of VMS and SFS reduced speeds by up to 16 km/h and lowered the percentage of vehicles speeding at US roadwork sites[1]

• SFS in a Korean school zone reduced average speeds by 8.2km/h (17.5%)[2]

• A literature review and meta-analysis found that SFS can be effective in reducing mean speeds, 85th percentile speeds, and the percentages of drivers over the speed limit in a range of contexts[3]

  
  

SFS devices range from small portable tripod and trailer-mounted units to fixed permanent devices on local, arterial roads and motorways.

[1] Austroads (2017). Safety at Road Worksites: Stage 1 Working Papers (AP-R544-17)

[2] Fitzpatrick et al. (2009). Speeds in school zones. Texas Transportation Institute.

[3] Fisher et al. (2021). Effectiveness of Dynamic Speed Feedback Signs Volume I: Literature Review and Meta-Analysis. National Highway Traffic Safety Administration, Washington.