You've done this: an oncoming motorist is driving with their bright lights on. So, you flash 'em with yours as a nudge to dim their brights. Makes sense, right? Outside the Cedar Valley there's a lot of rural roads. Or, perhaps you've flashed (or been flashed) to warn of a speed trap that's a ways up the road. Here's a question, have you ever stopped to think, "is this illegal?" After learning that in some states, like Michigan, it actually is if you are within 500 feet of them, I decided to dig in.

First off, I Googled. I researched Iowa driving laws. I found, in a word, nothing. So I decided I'd reach out to Black Hawk County Sherriff Tony Thompson who's a walking wealth of legal knowledge. He was kind enough to entertain my headlight question, which I posed to him as I did so above. His response leaves room for grey area:

There is a statute for “failure to dim”.  Flashing your headlamps unnecessarily could be written under that code (but it would be a jerk of an officer that did)

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Sherriff Thompson went on to explain that most motorists flash other drivers to warn them of a hazard or, as mentioned above, as speed trap and that is where things could get dicey:

While there is no Iowa Code precluding flashing your headlights, often people do that to warn on-coming motorists about dangers in the roadway… or law enforcement actions ahead (speed traps, inspection check point, etc), and if the flashing of headlamps impedes a law enforcement officer’s ability to their work, it could be charged under the “interference with official acts” charge of the code… but again, that is a bit of a stretch and hard to prove “intent” of the driver.

So there you have a concrete answer from Sherriff Thompson. The answer is, no it's not illegal. However... it can be depending on the mood of the police officer, or sheriff's deputy that witnesses the action assuming any do. Thanks to Bobby Guy from our sister station WRKR in Michigan for the inspiration to explore the topic.

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