Roadside thingamajigs, or mystery roadside furniture as more educated people might refer to them, are those things you’ve seen in your peripheral vision as you drive along and wondered “what on earth is that thing on the side of the road?”
Cameras, but not speed cameras
There are a number of different cameras in use throughout the UK. Apart from speed cameras, they fall into three main classes.
The first is the camera that measures traffic flow. The Highways Agency owns more than 1,500 in England alone (Wales and Scotland have their own schemes). They’re generally mounted on 12m high poles and live operators use them to gauge how well the traffic is flowing and to look at unfolding incidents in real-time.
Trafficmaster is a private company that installs dark-blue cameras long the road network to enable it to measure the traffic flow automatically. It uses this information to inform its subscribers of holdups, enabling them to reroute drivers around the obstruction.
The second type of camera is used for traffic offence enforcement capturing images of drivers doing things they shouldn’t, like driving in a bus lane. They can take photograph and issue a fixed penalty notice automatically using ANPR technology.
Speaking of which, the final category is the Automatic Number Plate Recognition (ANPR) camera. These can be use to identify and track a specific car for hundreds of miles if necessary as well as to check the details of every passing car against a central database to make sure they’re MOT’d, insured and taxed.
How you can avoid the number plate scam
White squares on the road
You will have driven over tens of thousands of white squares painted on the road, but do you know what they are for?
Depending on the exact shape and size they can either be used as nodes for surveying roads or the police for speed detection.
In the latter case, they’re part of VASCAR (Visual Average Speed Computer and Recorder), a fiendishly simple and clever technique the police use to measure your speed.
They simply time how long it takes you to pass over two of them, something that enables them to work out how fast you’ve been travelling. They can do this either because they know how far apart the two squares are, or by following you and measuring it.
The latter is extremely clever; the police officer simply presses a stopwatch as you pass over the first square and triggers a second button as he or she does, starting a calibrated odometer.
As you pass over the second marker, he or she turns the stopwatch off. As the police car passes over the same marker, the odometer is tuned off too.
From this information the onboard computer can calculate how long it took you to travel the distance in question – and it knows how far apart the two marks are from the odometer. (The police also use shadows on the road, roadside signs, bridges etc., to do exactly the same thing.)
It’s a simple, cheap and very, very effective way to catch speeding motorists.
Speeding myths dispelled
Two cables in the road
We’ve all driven over a pair of parallel thick cables lying on the road, and most of us will assume that they’re there to measure your speed, which is almost the right answer.
It’s an automatic traffic counter (ATC), which measures traffic flow, volumes and speeds. Some can even measure the weight of a vehicle passing over them, enabling it to work out the number of cars to HGVs etc.
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Saga readers ask...
'There are tall (often grey in colour) poles at the side of the road, usually near busy roads in built up areas. These are tall round, probably metal, about the height of street lighting, and have a larger part at the top of a larger diameter, and an apparently flat top. What are they?' Paul, via email
It sounds like it might be a mobile phone network mast - the name of the mobile phone company should be on one of the green cabinets behind it.
If your favourite thingamajig isn’t featured, let us know by emailing email@example.com and we’ll do our best to uncover its purpose!