Speed Indicating Devices (SID)

Many communities are concerned about the speed of traffic in their local area and in some cases this has a significant effect on their quality of life. The Safer York Partnership, through publicity and education, endeavour to help tackle this problem as part of the overall aim to reduce road casualties across the city.

The SID (Speed Indicator Device)

The SID (Speed Indicator Device) is one of a range of tools available which may or may not be appropriate for use at a given site depending on the results of an investigation under the speed review process. To action an investigation, you need to fill in a speed concern report form.

SID is of particular benefit when tackling the casual speeder who may not have realised that they are driving too fast or breaking the speed limit. SID notifies them of their speed and helps to make them more aware of potential hazards in the area and the appropriate speed at which they should be travelling.

A year-long evaluation in Dorset showed that speed reduction was achieved where SIDs were activated. Speeds of more than 325,000 vehicles were recorded following 70 deployments at 35 sites and results revealed that the average speed decrease was just over 5 mph when compared with average speeds before deployment. A similar, but smaller-scale survey carried out in Leeds at two locations during 2005 backs up this evidence, showing that where SIDs were deployed there was a noticeable reduction in the speed of traffic.

You can view the community SID leaflet.

Community Groups

We ask that volunteers represent a group such as a residents' association or parish council in order that the broader feelings of the community can be represented, rather than the feelings of one individual. It also means that there will be more volunteers on hand to operate the SID when deployed at the selected survey sites.

Permanently fixed SID signs

An advantage of SID is its portability, meaning that it can be used at a number of different locations throughout the community and set to work on roads with different speed limits. The very fact that the machines are located on a temporary basis means that road users notice their presence and respond accordingly.

SID data and number plates

SID has not been designed to automatically collect data, the idea of the machine is to educate drivers about the speed at which they should be travelling and to raise motorists' awareness in a positive way.

Recording our own data

Yes, this can be used for your own information, or in certain cases be passed on to the Road Safety Officer.

We do not recommend taking down number plates or even individual speeds except in exceptional circumstances. Data tends to be most useful when recorded in tally or tick form on a simple chart.

Upper speed thresholds

SID has an upper threshold limit set 15mph above the official speed limit of the road where it is being used. This is in order to minimise the chance that a minority of individuals may see the device as a target to see how fast they can travel though the area, using the roads as a race track.

Accuracy of the machine

SIDs rely on radar technology and are regularly calibrated by the Road Safety Promotion Team. This means that the machines remain fully accurate when placed at the roadside.

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