It's a little bit like neighborhood watch: an extra set of eyes and ears in case something suspicious is going on in your neighborhood.
It's called the Honk and Alert program.
Mail carriers will honk the horn three times, alerting residents they are there.
They'll do this every time they park the truck.
Fresno's post master is asking mail customers to keep watch, and report anything suspicious with the mail, the postal truck, or the mail carrier.
Lynn Carter, Fresno Resident: "We've had some break-ins in the neighborhood and we all try to look out for each other, but it's always good to have an extra pair of eyes."
In turn, mail carriers will also be keeping an eye on the neighborhood.
Robert Abina, Fresno Resident: "Our mailman, I've personally known him for about 7 years, and that wouldn't bother me, not one bit, to give me a little extra security, that he's out there, that way we can watch his back and he can watch our back."
The mailman Robert is talking about is David.
Things are relatively quiet in this part of David's route.
But mail thefts are a growing concern in many Fresno neighborhoods, and so is safety.
Eve Forrest, Fresno Post Master: "Our carriers have saved lives, put out fires, performed CPR, even found children that were lost."
Five zip codes in the city limits are currently using the honk and alert program. They are 93701, 93703, 93721, 93726, and 93728.
It's a little bit like a pilot program and Fresno's postmaster says there are no plans to extend this throughout the city just yet, but they want to see how this part of the city works with the program for now.
The post office is asking residents who see anything suspicious going on in their neighborhoods with postal vehicles to report it.
The number for the Postal Inspection Service is 877-876-2455.