A378 Traffic Speeds – Indicator Device Results

PDF      Fivehead Speed Indicator Device (A378 Green Shutters) – August 2016 (G)


Please note that the speeds shown 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.
The median speed was calculated at 35mph which is 5mph above the posted speed limit of 30mph.
The 85%ile speed was calculated as 43mph which is 7mph above the intervention limit of 36mph.
The 85%ile speed is the speed at which 85% of all vehicles are travelling either at or below, (with obviously the remaining 15% of all vehicles travelling at a higher speed)
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 36mph in a 30mph posted speed limit). Locations that equal or exceed the intervention level speed qualify for a Speed Indicator Device on a regular basis.


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