On I-495 near Silver Spring, Md., a sign reads: DUI Enforcement Area. Really? I’ve been driving under the assumption that every foot of roadway in America is a DUI Enforcement Area.

With so many motorists distracted nowadays by personal electronic gadgets – plus, of course, arguing with their spouses, fielding the kids' questions, eating, applying makeup, etc. – the last thing we need is signage that persons of reasonable intelligence can't understand. Worse, we don't need information that we're powerless to do anything about.

On the Massachusetts Turnpike near Westover AFB in Chicopee, there are signs saying: Caution Low-Flying Aircraft. I don't recall any tips in the drivers' manual about avoiding airplanes. It would make just as much sense to post a warning about periodic meteor showers. Besides, if a plane is so low that it threatens a five-foot high Pontiac then it's probably a little late for a written warning.

This spring Massachusetts replaced thousands of highway signs at a reported cost of $22 million, prompting some to wonder if such an expenditure at this point is, itself, a bad sign in terms of fiscal mismanagement.

On the highway heading to Freehold, N.J., I saw a permanent sign that said: Trees Sprayed with Noxious Spray. Aside from the fact that the sign maker apparently had a tough time finding a synonym for "spray" ("treated" might have worked), what are motorists to do? Turn back? Hold their breath? For how long?

Many highway signs are of little or no value to the driving public, but are posted for convoluted legal purposes so that government agencies can avoid culpability. I suppose when sued over the noxious sprays in New Jersey, government can say, "Well, we warned you." The same is true with the Highway Safety Corridor. Apparently it's an area in which traffic fines are doubled – and there's a legal reason to notify motorists that they’ve reached the end of that section.

Across Maryland, troubling signs of the times are posted on giant electronic boards. They give an 800 phone number and advise: Report Suspicious Activity. What’s that about? Should I report the guy who just cut in front of me at 90 mph? Or by “suspicious” do they mean, say, Arab-looking motorists who might have a package in the trunk that could be a bomb?

These digital, or “smart” highway signs are sometimes pretty dumb. On the New Jersey Turnpike – as in several states – electronic speed signs are left blank when there are no dangerous conditions. On such occasions the signs say SPEED LIMIT with no numbers posted, leaving motorists confused about what the proper speed really is. In some states the electric signs have resulted in varying speeds being posted in different lanes on the same highway.

Apparently the sign situation is so frustrating that a few motorists feel the need to inject comic relief. In Greenville, Del., last month the computer for an electric highway sign was hacked and the message changed to: Live Nudes Ahead.

In Maryland, there’s a highway overpass with the sign: Brooklyn Bridge Road. Someone with spray paint and a sense of humor added: 4 Sale.

And what’s ahead? A headline in the Albany, N.Y., Times Union warns: “Confusing road signs about to hit the highway.”

(c) Peter Funt. This column was originally distributed by the Cagle Syndicate.