Q. The street sweepers that clean residential streets use water to cut down on dust. Why doesn’t Caltrans use the same type of sweeper? It looks like a dust storm when freeways are being cleaned. Also, what is the schedule of the sweepers?

– Brian Ota, Diamond Bar

A. Not sure if the sweepers are all the same, but the strategy apparently is.

Caltrans’ sweepers do use water, said Sheilah Fortenberry, a spokeswoman for the agency, relaying info from the Maintenance Manager’s Office, and for the reason you mentioned, Brian, to keep the dust down.

The sweepers tend to roll during the day, even though there is more traffic then, because they can be seen so it is considered the safest time. How often they operate on a specific freeway stretch can depend on how quickly stuff has collected.

They oftentimes travel in groups: A truck leads the way, with the driver able to hop out and pick up debris that could hurt the sweeper such as wire, soft materials larger than a shoe and retreads; at least one sweeper follows and then, for safety, there might be a California Highway Patrol squad car and a vehicle with a gigantic cushion on the back to absorb any errant drivers.

These sweeper trains generally stay to freeways’ shoulders, because anything spilled tends to end up there, although a sweeper tackles the middle lanes when debris ends up there, the Caltrans’ representative from the Maintenance Manager’s Office said.

Q. We decided to take a day trip to Temecula with our daughter. We used our car, but our son-in-law added it to his 91 Express Lanes account for one-day usage. He may or may not have done that right. About three days later I received this letter I forwarded to you, Honk. All of the info (date, time, place and license-plate number) is correct. The fine for using the lanes illegally is not really $25, is it? Is this letter a scam?

– John Billings, Long Beach

A. The violation notice you sent to Honk looks legit, John, but you can call the 91 Express Lanes’ customer-service line to make sure at 800-600-9191.

And Honk does have good news:

A policy of the Orange County Transportation Agency, which owns the 10-mile stretch of those toll lanes from the 55 Freeway to the Riverside County border, is it will consider waiving a first violation if the driver made a mistake, said Joel Zlotnik, an OCTA spokesman.

Plead your case, John.

Now, what your son-in-law could have done – and maybe he did – was call customer service to get your vehicle added to his account. You would get a transponder sticker for your windshield, which is required.

But let’s say you forgot to stick yours onto the windshield – the device that detects the transponders would activate a search of the database for your license-plate number, determine your vehicle was tied to a valid account and charge the toll, but not any penalty.

To ask Honk questions, reach him at honk@ocregister.com. He only answers those that are published. To see Honk online: ocregister.com/tag/honk. Twitter: @OCRegisterHonk