How they track semis on the I-5

Dear Matt: Picture this. I’m driving home from L.A. on the 5, approaching San Onofre. I pass under what looks like an overhead street lamp, only instead of a lamp, there's what looks like a Dustbuster on the end...and it's pointed at ME! It's got a big, thick, electrical-lookin’ cable comin’ out of the back, so I know it’s got power. What is it? Should I cover the jewels with lead while racing by below it in my little metal truck? I have to drive to L.A. every weekend this summer, and my paranoia will only grow. I’m scared. Matt. Help. — Papercut, e-mailville

No need for us to picture this. The estimable Mr. Geary’s already taken care of that. Today marks Rick’s 20th anniversary as director of cinematography and special effects for Team Matthew Alice. Two decades of turning your aimless ponderings into clever visuals. To celebrate, the research elves pitched in and bought him a new set of felt pens and free emergency psychiatric care for the next ten years.

So now that we’ve got the picture, Papercut, you can uncover those jewels. It took a little snooping, but I think we’ve got the cuffs on the perp. According to the California Highway Patrol, the Big Dustbuster is a semi detector. A truck tracker. It lets the nearby truck weigh station know when a customer’s coming. Trucks are required to check in at weigh stations, and, according to the CHP, the overhead detector senses a signal from the semi and delivers it to the weigh station so they can make sure they stop. They don’t care about your little metal truck or the jewels. Just the big guys.