Summary of Speed Indicator Device (SID) and Community Speed Watch (CSW) Activity
For the period 24th April to 22nd August 2025
Salisbury Road Secondary SID Site
SID was at this location from 24th April to 3rd June 2025
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Blandford Road Secondary Road SID Site
SID was at this location from 4th June to 27th June 2025
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Tottens Farm SID Site
SID was at this location from 2nd July to 22nd August 2025.
For the latest on Community Speed Watch
For more information regarding approved SID sites in Coombe Bissett and Homington villages please refer to the SID location Power Point guide.
Summary of Driver Behaviour Recorded by our SID
Periods 24th April to 3rd June 2025 and 4th June to 27th June 2025
The information gathered from the SID during these two periods was used to complete a presentation to the Coombe Bissett and Homington Parish Council to evidence the effectiveness of Speed Indicator Devices in controlling traffic speeds in our communities. The presentation was prepared at the request of our Councillors to support a proposal made at the meeting on 13th May that we should purchase a second SID. The Parish Council has agreed, in principle, that SIDs are effective and are currently considering how to afford the purchase of a second device. The following slides are taken from some of the material presented to the Parish Council.
The information gathered from the SID during these two periods was used to complete a presentation to the Coombe Bissett and Homington Parish Council to evidence the effectiveness of Speed Indicator Devices in controlling traffic speeds in our communities. The presentation was prepared at the request of our Councillors to support a proposal made at the meeting on 13th May that we should purchase a second SID. The Parish Council has agreed, in principle, that SIDs are effective and are currently considering how to afford the purchase of a second device. The following slides are taken from some of the material presented to the Parish Council.
The shortest detection range of our SID falls outside the start of the 20 mph zone when the device is in this location facing traffic from Nunton and Odstock. We display speeds to incoming drivers to encourage them to slow down before they enter our community. The device nevertheless is picking up vehicle speeds from the 50 mph section of the Homington Road, just outside Tottens Farm. As such, the above information shows driver behaviour as they leave or about to enter Tottens Farm. For this reason, we do not submit this data to Wiltshire Police to load on their SID Database.
With the SID facing into the village it is picking up vehicle speeds approx. 100-120 metres inside the 20 mph speed limit zone. While 85th %ile speeds are still too high, average speeds in both directions are acceptable. Unfortunately, we cannot legislate for individuals who insist on speeding. We continue to encourage the Community Speed Enforcement team to spend time at this location to monitor such drivers and prosecute those who ignore the speed limit through Tottens Farm.
I would like to take this opportunity to thank Carola and Chris Thomas for all their help and support in changing batteries and moving our SID around its various locations in Coombe Bissett. Following Chris’s decision to retire from the SID support team and I am pleased to say that Duncan Scott has now joined team to make up our numbers. Our thanks also go to Simon Boxall and Chris Humphreys for helping with the SID when it is located in Homington.
I would like to take this opportunity to thank Carola and Chris Thomas for all their help and support in changing batteries and moving our SID around its various locations in Coombe Bissett. Following Chris’s decision to retire from the SID support team and I am pleased to say that Duncan Scott has now joined team to make up our numbers. Our thanks also go to Simon Boxall and Chris Humphreys for helping with the SID when it is located in Homington.
For details of traffic speeds for each SID session and comparisons with earlier data please go to the location tabs which form part of this web page.
Detailed PDF reports:
Note: Our SID does not have GPS and therefore its reports are location agnostic. References in reports to Incoming and Outgoing traffic refer to traffic coming towards the device (Incoming) and traffic going past the device in the opposite direction (Outgoing).
Note: Our SID does not have GPS and therefore its reports are location agnostic. References in reports to Incoming and Outgoing traffic refer to traffic coming towards the device (Incoming) and traffic going past the device in the opposite direction (Outgoing).
Wiltshire Speed Indicator Device Data Sharing
SID Data Sharing has been rolled out across Wiltshire for more than a year. There are over 100 SIDs installed in towns and parishes across Wiltshire. Communities who have purchased Evolis, MessageMaker, Pandora Technologies or Westcotec devices are able to share their data with Wiltshire Police who use the information to prioritise the deployment of Wiltshire Police’s Speed Enforcement resources.
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Community Speed Enforcement Officer (CSEO) Team
The CSEO team have been conducting roadside speed enforcement sessions in Coombe Bissett, using the CSW Deegan House location. Debbi Hide of the CSEO team advises she has carried out speed checks at 9:30 to 10:30 am; 12 pm to 1 pm and 2 pm to 3 pm. A summary of CSEO reports is as follows: |
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Community Speed Watch (CSW) Update
A total of 37 Speed Watch sessions were conducted between 24th April and 22nd August 2025
The team continues to conduct 2-3 speed watch sessions each week. Traffic volumes increased significantly in Homington and Tottens Farm in the last 3 weeks of August as a result of Road Works on the A338 between the BP station and the Park and Ride. Drivers have taken to using the C12 road via Nunton and Odstock. The number of reported speeding drivers has increased accordingly.
The community should appreciate the efforts of all CSW team members who have given up their own time to remind drivers to drive with due care and attention when passing through Coombe Bissett and Homington. For that we are indebted to Gillian Irving, Gerald Bundy, Kim Byatt, Michael Wardroper, Gill and Chris Humphreys, Sol Rimer and Simon Boxall for their commitment and ongoing support.
Thank you!
I am happy to report that Christine Swatton and Chris Edwards both responded to the call for new volunteers which was placed in the last issue of the CB+H Express. Both took part in Speed watch sessions following which they have applied to join the Wiltshire Community Speed Watch team and have started their on-line training. Well done Christine and Chris!
The community should appreciate the efforts of all CSW team members who have given up their own time to remind drivers to drive with due care and attention when passing through Coombe Bissett and Homington. For that we are indebted to Gillian Irving, Gerald Bundy, Kim Byatt, Michael Wardroper, Gill and Chris Humphreys, Sol Rimer and Simon Boxall for their commitment and ongoing support.
Thank you!
I am happy to report that Christine Swatton and Chris Edwards both responded to the call for new volunteers which was placed in the last issue of the CB+H Express. Both took part in Speed watch sessions following which they have applied to join the Wiltshire Community Speed Watch team and have started their on-line training. Well done Christine and Chris!
If you would like to become part of the Community Speed Watch team and help us in our efforts to improve road safety in the parish, please don’t hesitate to call Adrian Turnbull on 07747 620210 or email me at [email protected] .
Thank You!
Thank You!
NOTE EXPLAINING INFORMATION IN PDF REPORTS
OF SPEED INDICATOR DEVICE (SID) ACTIVITY
COVER PAGE
The start and end dates for the period the device has been active at a location are shown on all pages.
Location: Records where the SID device was positioned during the report period and is shown on all pages.
Note: The Parish Council agreed that the SID should serve as much of the community as possible. Sites have had to be agreed by Wiltshire Council. At present there are a total of 7 approved sites. Details of exactly where each site is located are available in a separate document.
Comments: Details here show the speed limit for the site where the SID was located and the direction of traffic the SID was monitoring at that location:
- Inbound relates to traffic coming into the village
- Outbound relates to traffic leaving the village
The Comments section also states whether the sign was actively displaying the speed information to oncoming traffic or if it was in ‘Spy Mode’. Spy Mode records traffic information but does not display speeds, and is used to baseline traffic speeds at the start of the period.
PAGE TWO: AVERAGE SPEEDS
The Average Speeds graph includes two averages:
- An ‘average by time period’, which is displayed as a curve on the graph. (one curve per direction: ingoing/outgoing).
- An overall average which is displayed as a numeric value just below the graph.
The ‘average by time period’ corresponds to the arithmetic average calculated on the speeds recorded between the start/end dates. They are presented on a default time period of 30 minutes. The overall average corresponds to the arithmetic average of all the speeds included between the starting/ending dates on the time period selected for the PDF report. The software sums up all of the recorded speeds, then divides the result by the number of vehicles measured.
Note: References in the PDF report to Incoming direction and Outgoing direction relate to the direction of traffic in relation to the SID. ‘Incoming’ relates to traffic heading towards the device. ‘Outgoing’ relates to traffic going past the device in the opposite direction
PAGE THREE: MAXIMUM SPEEDS
Similar to the information for average speeds, the graphs relating to maximum speeds are displayed in curve and number format.
- The maximum speed recorded per time period are displayed in graph form (oncoming and outgoing are reflected in different colours).
- The maximum speed recorded over the entire time period is shown for each direction as a numeric value just below the graph.
PAGE FOUR: VEHICLES PER HOUR
Graphs show traffic volumes for incoming traffic (Green) and outgoing traffic (Blue) for each 24-hour period covered by the report. Total volumes are shown at the top right of the graph
PAGE FIVE: SPEED DISTRIBUTION FOR INCOMING TRAFFIC
PAGE SIX: SPEED DISTRIBUTION FOR OUTGOING TRAFFIC
In these sections, the recorded speeds are represented in pie chart form, and allow you to see the percentage of vehicles which have, or have not, observed the speed limit.
The first segment shows the percentage of vehicles which are travelling below or at the legal speed limit in that location. The second segment shows the percentage of vehicles which are travelling above the legal limit but approximately within the speed tolerances permitted by Wiltshire Police and Community Speed Watch before drivers may be sanctioned. The remaining segments show the percentage of vehicles travelling at excessive speeds.
PAGE SEVEN: PERCENTILES FOR INCOMING TRAFFIC
PAGE EIGHT: PERCENTILES FOR OUTGOING TRAFFIC
The 85th percentile is an indicator that helps illustrate the behaviour of the majority of drivers. It reflects the speed respected by 85% of motorists and is obtained by stripping out the bottom and top & bottom 7.5% of speeds recorded (i.e. strips out the extremely fast and extremely slow vehicles).
If the 85% threshold is close to the average speed recorded, this indicates that the speeds observed on a road are consistent. If it is not close to the average speed, this means that a significant proportion of drivers are above the average recorded speed.
Note: Wiltshire Police use 85th Percentile speeds to determine whether they should conduct their own Speed Checks in any location. This is normally determined by the use of a Traffic Speed Survey which is sometimes referred to as a Metro Count. It involves two rubber strips placed across the road connected to a recording device. To-date, the Parish Council have had to request Speed Traffic Survey reports on a case by case basis, before any Police enforcement action will be considered.
The start and end dates for the period the device has been active at a location are shown on all pages.
Location: Records where the SID device was positioned during the report period and is shown on all pages.
Note: The Parish Council agreed that the SID should serve as much of the community as possible. Sites have had to be agreed by Wiltshire Council. At present there are a total of 7 approved sites. Details of exactly where each site is located are available in a separate document.
Comments: Details here show the speed limit for the site where the SID was located and the direction of traffic the SID was monitoring at that location:
- Inbound relates to traffic coming into the village
- Outbound relates to traffic leaving the village
The Comments section also states whether the sign was actively displaying the speed information to oncoming traffic or if it was in ‘Spy Mode’. Spy Mode records traffic information but does not display speeds, and is used to baseline traffic speeds at the start of the period.
PAGE TWO: AVERAGE SPEEDS
The Average Speeds graph includes two averages:
- An ‘average by time period’, which is displayed as a curve on the graph. (one curve per direction: ingoing/outgoing).
- An overall average which is displayed as a numeric value just below the graph.
The ‘average by time period’ corresponds to the arithmetic average calculated on the speeds recorded between the start/end dates. They are presented on a default time period of 30 minutes. The overall average corresponds to the arithmetic average of all the speeds included between the starting/ending dates on the time period selected for the PDF report. The software sums up all of the recorded speeds, then divides the result by the number of vehicles measured.
Note: References in the PDF report to Incoming direction and Outgoing direction relate to the direction of traffic in relation to the SID. ‘Incoming’ relates to traffic heading towards the device. ‘Outgoing’ relates to traffic going past the device in the opposite direction
PAGE THREE: MAXIMUM SPEEDS
Similar to the information for average speeds, the graphs relating to maximum speeds are displayed in curve and number format.
- The maximum speed recorded per time period are displayed in graph form (oncoming and outgoing are reflected in different colours).
- The maximum speed recorded over the entire time period is shown for each direction as a numeric value just below the graph.
PAGE FOUR: VEHICLES PER HOUR
Graphs show traffic volumes for incoming traffic (Green) and outgoing traffic (Blue) for each 24-hour period covered by the report. Total volumes are shown at the top right of the graph
PAGE FIVE: SPEED DISTRIBUTION FOR INCOMING TRAFFIC
PAGE SIX: SPEED DISTRIBUTION FOR OUTGOING TRAFFIC
In these sections, the recorded speeds are represented in pie chart form, and allow you to see the percentage of vehicles which have, or have not, observed the speed limit.
The first segment shows the percentage of vehicles which are travelling below or at the legal speed limit in that location. The second segment shows the percentage of vehicles which are travelling above the legal limit but approximately within the speed tolerances permitted by Wiltshire Police and Community Speed Watch before drivers may be sanctioned. The remaining segments show the percentage of vehicles travelling at excessive speeds.
PAGE SEVEN: PERCENTILES FOR INCOMING TRAFFIC
PAGE EIGHT: PERCENTILES FOR OUTGOING TRAFFIC
The 85th percentile is an indicator that helps illustrate the behaviour of the majority of drivers. It reflects the speed respected by 85% of motorists and is obtained by stripping out the bottom and top & bottom 7.5% of speeds recorded (i.e. strips out the extremely fast and extremely slow vehicles).
If the 85% threshold is close to the average speed recorded, this indicates that the speeds observed on a road are consistent. If it is not close to the average speed, this means that a significant proportion of drivers are above the average recorded speed.
Note: Wiltshire Police use 85th Percentile speeds to determine whether they should conduct their own Speed Checks in any location. This is normally determined by the use of a Traffic Speed Survey which is sometimes referred to as a Metro Count. It involves two rubber strips placed across the road connected to a recording device. To-date, the Parish Council have had to request Speed Traffic Survey reports on a case by case basis, before any Police enforcement action will be considered.
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