Ask of the Week: Why are so many cars driving in poor visibility with no rear lights?

Dear HonestJohn,

"Driving in poor visibility today I noticed lots of cars with no rear lights on, despite the fact that their front lights were on. It was various makes and models but mostly newer cars. Is this a function of auto lights? If so I certainly didn’t realise it. Can you throw any ‘light’ on it?

- EP

Dear EP,

Cars fitted with automatic lights should have their lights on according to the lighting conditions, assuming they are working properly and the driver actually has the lights set to automatic.

Cars fitted with daytime running lights will provide some degree of forward lighting at all times but if the instrument lighting is illuminated it might fool the driver into thinking that their dipped headlights are on when they are actually running on DRLs alone.

As always, a car is only a smart as the person operating it. If you prefer to turn your dipped headlights on and off manually, it is important to ensure they are on the correct setting for the conditions.

Other than wearing the bulbs out more quickly and the potential for a minute increase in fuel consumption, leaving dipped headlights on all the time is safer - studies have shown your chances of being involved in an accident can be reduced by a third when using dipped headlights at all times.

If you have automatic headlights, we would recommend using the automatic function at all times, as it ensures you will have the correct lights on when required-  including situations where the driver might not automatically do so, such as in poor weather or tunnels. It also prevents the driver from leaving their lights on and draining the battery when leaving the vehicle.