Printer friendly page

SIDs work if used sparingly, Dorset says

A year-long evaluation of Speed Indicator Devices (SIDs) in Dorset suggests that speed reduction can be achieved where they are activated - if they are used sparingly.

Evaluation of the effectiveness of SIDs at 35 sites across rural Dorset suggests an average speed decrease of 5mph during deployment.

Demand for deployment of SIDs in Dorset is growing and a protocol has been introduced to deal with the flood of requests from parish councils and members of the public for the popular devices, which flash up a drivers' speed on approach.

Speeds of more than 325,000 vehicles were recorded following 70 deployments at the 35 sites and the results reveal that the average speed decrease was 5.26mph when compared with average speeds before deployment. At one site speeds decreased by more than 40%.

Most sites are in rural villages with 30mph speed limits where there is evidence of inappropriate speed, and a formal request for a SID has been received from the local parish council.

Evaluation is now taking place to determine whether vehicle speeds continue to be reduced when the SID is removed after a week.

Early results suggest that SIDs should perhaps be deployed on a regular basis at different sites, but not too frequently as the effect on regular commuters can be diluted.

A study along one route where SIDs have been deployed almost every other week suggest the average decrease in speeds is not sustained compared with sites with longer gaps between deployment.

Dorset County Council's road safety team leader, Robert Smith, says: "SIDs are extremely popular with parish councils and most members of the public - they are a non-threatening way of reminding drivers of their speed.

"It is important to evaluate road safety education interventions such as this and SID deployment is one that is relatively straightforward."

Further details are available from Dorset County Council road safety team on 01305 224548,  j.cheeseman@dorsetcc.gov.uk