There was an article on the Speedcam Anywhere app in the Road CC website and a few comments where readers had not understood how it works. I posted the following as an explanation and thought it might be useful.
Most speed detection "devices" use a function within the device to measure the speed of a vehicle. If its rad or laser it involves measuring the speed by bouncing a wave off the oncoming vehicle and measuring the doppler effect produced because the vehicle is moving. One issue with this is that you can rarely use the device in the path of the vehicle and therefore you do not measure the vehicle speed as it is reduced by the cosine from the sight line to the direction of travel. Because the device independently assesses the speed it needs calibration.
Spartcam Anywhere is different. It is not the smartphone that measures the speed. The ap buffers a video image and when you press the shutter as a car is passing and centred on the screen it selects a video snip of the previous 1 sec and next 1 sec. This is then uploaded to the cloud together with GPS location. The server then :-
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Uses ANPR to look up the vehicle make, model and year.
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Looks up the wheelbase of the vehicle. (WB)
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Uses AI to analyse the video and locate the wheel centres.
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Finds the still in the video clip where the front wheel passes a point on the road. Takes its time stamp. (T1)
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Finds the still in the video clip where the rear wheel passes the same point on the road. Takes its time stamp. (T2)
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Uses the simple physics calculation that v=s/t ie v= WB/(T2-T1)
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Looks up the mapping to find the speed limit at that point.
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Creates a two second video clip overlaid with the time stamps
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Creates an A4 report showing location, picture of vehicle, its details,location, speed and speed limit as well as time stamped stills used.
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Sends a summary back to the app
The app user is then able to download the report and video clip for upload to the police dashcam. Here police can (if they wish) examine the video to verify the speed of the vehicle.
Because the wheels always follow the direction of the vehicle the angle of approach does not matter. You can use the app with oncoming or departing cars as long as you can see the number plate. A line of site with one edge of the image perpendicular to the road has been found to work best.
The requirement for a Home Office Type Approved device only exists for speeding convictions. It is an anomaly that presumes that the speed is actually measured on the device. Where it is a video, precedents have already been set whereby drivers have been prosecuted for careless or dangerous driving based on video evidence. This includes verifying speeding. However this does require expert analysis and often a measurement of road markings or scenery to provide a fixed distance to measure the travel time over. Speedcam Anywhere negates the need for this expert analysis by using AI and the wheelbase of the car as a fixed distance.
Section 59 Anti Social Driving offence only requires reasonable grounds for believing that a motor vehicle is being used on any occasion in a manner which contravenes section 3 or section 34 of the Road Traffic Act 1988 (careless and inconsiderate driving and prohibition of off-road driving) and is causing, or is likely to cause alarm, distress or annoyance to members of the public. Hence under "reasonable grounds" a Section 59 offence can be registered. Speedcam Anywhere could gain Type Approval for the "process" rather than the "device". In which case police and members of the public may use it for enforcement of speeding offence directly.
This really does use a great combination of modern databases, smart analysis and AI to provide an accurate measurement of speed using a Smartphone. Its not only a great invention but also a huge step forward for enforcement. When driving in future then any pedestrian you see could be a Speedcam Anywhere pedestrian. Especially in urban and village settings drivers should be wary of blasting through those public places between buildings that we call streets. After all 20 is Plenty where people are.
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