Please find attached the latest speed indicator device, (SID), reports for Bridgwater, (NDR – east bound), taken between the 21^st August 2015 and the 3^rd September 2015.
The median speed for August and September was calculated at 34mph which is 4mph above the posted speed limit of 30mph. The 85%ile speed was calculated as 40mph for August and 39mph for September which is 4mph and 3mph respectively above the intervention limit of 36mph.
The speeds shown in the report are the approach speeds of vehicles as recorded by the device and do not reflect the ‘adjusted’ speeds which the motorists may switch to on being ‘reminded’ of the posted speed limit by the device. This means the speeds shown are probably an accurate reflection of the speeds normally experienced at this location. Where we have been able to measure ‘adjusted’ speeds at other locations we have found there has been a reduction in speed between the approach speed and adjusted speed of approximately 4-5mph.
The intervention limit is the speed, (under the current policy), at which a location is deemed to have a speeding issue. It is calculated by taking the posted speed limit, adding 10% and then adding a further 3mph, (this equates to 25mph in a 20mph posted speed limit; 36mph in a 30mph posted speed limit and 47mph in a 40mph posted speed limit). Locations that equal or exceed the intervention level speed qualify for a SID installation on a regular basis, (please note this location is already included in the SID programme and will therefore continue to receive a temporary SID on a regular basis).