Inspecting millions of items

This is a management problem without an obvious solution.  In the U.K., private motor vehicles must - by law - pass a test each year.  It is called the "MOT test", and people talk about "going for the MOT", even though the Ministry Of Transport (MOT) is now the DVLA (Driver & Vehicle Licensing Agency) and MOT tests come under the ambit of the Vehicle and Operator Services Agency (VOSA).  Every car four years old and more (it used to be three) must have a certificate to allow it to use the roads.  It certifies that the vehicle is roadworthy ... at the time of the test, and various writers have pointed out that this says nothing about its state on the next day, the next week or the next month.  Nonetheless it is a basic form of regular inspection, and these days most cars are so reliable that many drivers have their MOT at the time of a regular service and the car gets no other attention for months - unless a mechanical problem becomes apparent. 

Years ago, learner drivers were advised to check their cars daily or weekly, but these instructions are seldom given or observed these days. 

But some car components do deteriorate.  Go out on any road in Britain, and it won't be long before you see a car with defective lights.  Brake lights, side lights, rear lights, headlights - all fail randomly, or develop faulty electrical connections.   And the driver is probably unaware of such failures.  In Operational Research courses about inspection and maintenance, electrical items like bulbs are cited as ones which have a constant failure rate after their initial settling down period.  So, to a first approximation, they can fail at any time, irrespective of age.  OK, some expensive cars do have warning lamps to convey that something is wrong, but most models do not. 

 Some failures of lights are inconvenient, others can cause accidents.  A car with no lights on one side may be mistaken for a motorcycle.  A car with no brake lights does not give the following vehicle a warning that it is slowing.  I once followed a car at night on a very dark country road whose rear lights had a short circuit - every time the driver hit the brakes, ALL the rear lights went out!  I don't know how many accidents each year can be attributed to vehicles with faulty lights.  Since every serious road accident costs society many tens of thousands of pounds, there is an economic reason for trying to reduce the number of these.

What the test covers

So, how can the problem of so many cars with defective lights on British cars be dealt with?   Having defective lights is an offence for which the driver can be stopped on the road.  One answer might be to repeat the advice given years ago - check your car regularly.  For lights, that means two people to check things (unless you use a brick on the brake pedal).  Can you nudge people's behaviour to do this?  (Because the majority of cars these days are left on the road or in a drive, not in a garage, one form of visual check has been lost - parking a car in a garage gives the opportunity to observe some of the lights from reflections on the walls.)  Another might be to encourage those who work in car parks to be "checkers" - either to speak to a driver or to leave a note on the windscreen.  If there were a way for drivers to communicate with the car in front in a queue, then one could envisage a way to point out defective brake and rear lights.  But I wonder if there may be an answer in the "Internet Of Things".  A traffic surveillance camera with vehicle recognition equipment could identify a car whose lights didn't operate properly.  That information could be communicated to the vehicle's owner - or to the vehicle itself.  But it probably isn't a priority for electronic development of road systems.