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Spokane, Washington  Est. May 19, 1883

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Scrutinize those driving tips

I received a reader email with a couple of driving tips that especially apply as winter approaches.  Sometimes, simple reminders like these may thwart an accident or save a life — just be certain that it’s good advice before you heed it.

Reader R.L. actually forwarded a widely-circulated Internet piece that encourages drivers to use sunglasses when driving in the rain, while admonishing them for using cruise control when the roads are slick.

An excerpt from advice for driving-in-a-downpour suggests, “In the event you face such a situation, just try your sunglasses (any model will do), and miracle!  All of a sudden, your visibility in front of your windshield is perfectly clear, as if there is no rain.”

Like much advice, these “sage” words are only partly true.  Wearing POLARIZED sunglasses during the DAYTIME in the rain will indeed improve vision.  Their lenses screen and block horizontally reflected or scattered light, greatly reducing extraneous glare created during rainfall, improving overall vision.

The recommendation goes on to claim, “You can see where the rain bounces off the road. It works to eliminate the ‘blindness’ from passing semis spraying you too.”  Again, correct if the driver is using polarized sunglasses in the daytime.  The glare off the road itself is eliminated by the special characteristics of the lenses and the scattered light from the rain and spray is greatly reduced.

Using non-polarized sunglasses (“any model,” as suggested in the above tip) will hinder, rather than help you to see when driving in the rain.  Wearing regular sunglasses only darken your view, and will generally make vision during rainstorms worse instead of better.  In the interest of clarity:  Donning dark, non-polarized sunglasses while driving in a rainstorm will increase exposure to the hazard and compromise your ability to accommodate it.

If you heed the heavily publicized advice to wear sunglasses while driving in the rain, be sure that the ones you are using have polarized lenses.  Also, no sunglasses improve vision at night.  Though an unquoted excerpt from the same Internet “wisdom” implies otherwise, wearing them during night driving is unsafe.

Another recommendation that is regularly included in this Internet meme is the caution to avoid using cruise control in the rain. The wording in this particular forwarded email was typical, simply stating, “Never drive in the rain with your cruise control on.”

Unlike the partly true advice to wear sunglasses in the rain, the warning not to use cruise control when the roads are wet (or snowy, or icy) is wholly true.

Snowy, icy, or even rain-soaked roads lack optimum grip for your vehicle’s tires.  When your conveyance begins to hydroplane or develop wheel spin, power to the wheels must be reduced.  If the cruise control is engaged in such a scenario, engine power will be altered erratically.  The time required for a driver to disengage cruise control before tending to a vehicle that is about to spin is likely too great.  On those occasions, a driver must react immediately to have a chance at avoiding the spin, and any extra time wasted before doing so could prove catastrophic.  The mechanical interference from the cruise control mechanism at those times (unpredictable power to the wheels during lack of traction) can also quickly exacerbate the situation to the point of impossible recovery.

The best advice for driving in foggy, rainy, or snowy conditions is to not drive “over your head.”  In other words, if weather and road conditions deteriorate to levels that you are uncomfortable with, don’t drive.  In many cases, the most severe conditions pass rather quickly and you can head out on the roadway when things improve; often, you’ll then see the vehicles of drivers who tried to conquer the storm resting in the ditch.

Generic driving tips abound; one can find them printed here, there and everywhere.  Like the two discussed here, some are true and others are partly true.  Unfortunately, some published driving advice is false, or even downright dangerous.  Always take a critical look at widely-circulated Internet advice.  If something sounds odd, check it out with a driving professional (like a state trooper), or do some further research.

Readers may contact Bill Love via email at precisiondriving@spokesman.com.