I ran the filthy Mom-mobile through the car wash this evening, and right before the entrance was a large sign stating, “For safety reasons, cell phones must be turned off.”
I asked the attendant why, but he didn’t know; he just said that was the rule.
Okay, Dopers, why?
So you’re not distracted?
Does the car wash (all computerized) use radio frequencies?
Two possibilites spring to mind:
1.) So you’re not blabbing away on the thing and do something stupid like drive into a wall or the car in front of you.
or
2.) There’s an exceedingly remote possibility that the radio waves from your cell phone could cause problems with some of the equipment.
Another WAG:
The car wash might be giving off a big enough EMF that it could harm the ciruits of an On cell phone. Can’t imagine what the source of the EMF would be.
“I have heard stories” of people getting stuck in little car washes behind gas stations and calling the clerk on the phone to rescue them. (Including one story where the clerk didn’t believe them.)
Water can also degrade microwave radio signals making the cell phone more likely to cut out, but that’s not justification for a sign. (Else buildings with a lot of metal …)
Okay, I’m leaning towards the “distraction” theory.
I can’t imagine a car wash would be giving off a big EMF. Would it?
And after asking the hubby, he doesn’t think the computerized controls would bother anything, either.
When GPS becomes more common, will gas stations & car washes require us to turn those of too? After all, they transmit a signal not unlike that of a cell phone.
I can’t think of a reason why a modern day cell phone needs to be turned off in either a gas station or a car wash. The owners of these establishments probably are cowering to public paranoia and figure that, whatever the risk is (if there is one at all), that risk is extinguished when the phone is turned off. Following that logic we should also turn off our cell phones in donut shops and day care centers. (think of the children!)
GPS units in them selves are receivers and do not transmit any RF energy. Or at least not anymore than any other equipment with a computer inside. Now a GPS unit that is tied to a reporting system such as those used by trucking companies to track their vehicles are a different story.
I’d just add that I’ve noticed that a lot of convenience stores have signs posted inside saying to turn off cell phones because “they can interfere with equipment.”
Possibly the “equipment,” though, is the clerk.
A legitimate reason for a Gas station or car wash to post a sign telling you to turn your cell phone (or GPS receiver) off: If they don’t, and something happens (not even necessarily caused the the phone or GPS) they may get sued because they should have had the sign posted. Better to just post the sign for no reason.
Cell phones radiate RF energy. This energy can cause digital systems to malfunction (you can flip a bit, which means that valve that used to be off is suddenly now on, or maybe it was the reset line which causes the whole computer to crash) Any reasonable system should be designed to handle a lot more than the energy output from a cell phone, but you never know. If the car wash is some ancient completely mechanical system, there’s nothing to worry about, but if it has a little computer controlling everything, the “theoretical” worst that could happen is that things could turn on and off when they aren’t supposed to, possibly damaging your car, killing the operator, etc.
The likelihood of such an event is on par with the survival rate of a snow ball in hades, but then there’s the lawyers to consider…
Here’s the choices: 1) possibly millions in damages if the unthinkable and unlikely happens, or 2) a 30 cent sign.
Guess which one the lawyer will choose?