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rainy autobahnChristian Müller/Getty Images/iStockphoto

Every time I drive in fog, I wonder why cars aren't equipped with mandatory rear daytime running lights (DRLs). It's mandatory for the front headlights, why not the rear? – Pat

A topic near and dear to my heart – mandatory DRLs are a significant and proven safety feature. But the way the regulation is written, and the fact they are not mandatory in the United States, has led to some sloppy practices – such as wiring them so they operate in conjunction with instrument panel lighting.

While this may be a simple step during the manufacturing process for vehicles destined for Canada, it leads to people driving around thinking their headlights are on because they see light from the dash and front of the vehicle.

The light from the front of the vehicle is only partial, but the big problem is that the tail lights are not on, making the vehicle invisible from the rear in low light conditions and after dark.

Opposition to mandatory rear lighting might involve unnecessary use of energy. But in the new world of LED lights (that use practically no power and have a long life expectancy), that argument carries no weight.

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