Other mistake: They go to Texarkana, Texas, to pick up the beer, and later in the movie, they are in Fayetteville, Arkansas. Why would they go due north to Fayetteville to get to Atlanta, which is East?
Other mistake: When the Snowman is figuring out their schedule and he is typing on the calculator, you can clearly see that it's off. (00:18:15)
Other mistake: Just after Bandit and Snowman leave home for the trip to Texarkana they have to drive through some rain. As the Trans-Am approaches the camera there is someone in the passenger seat even though Bandit is alone in the car and they haven't picked up Frog yet.
Other mistake: When we first see a shot of Bandit's CB radio, you'll notice that it's a Pace Cb-166, and the microphone has a circular Pace logo. Later in the movie when Bandit picks up Frog, and he's holding the mic up as she's rambling to trying to get off her wedding dress, you'll see the mic has a different rectangular logo (still a Pace model mic, but different from the one initially shown. (00:18:06 - 00:25:13)
Other mistake: The stop sign at the side road that the van pulls out from is actually facing in the direction that the Bandit is coming from and not the direction the van was coming from.
Answer: The trooper on the motorcycle had just landed in the water. In older days, the typical day to take a bath, wash hair, etc. was Saturday. The trooper in the car (once he saw the motorcycle trooper was okay and wet) just made a joke about him taking a bath.
Zwn Annwn
It was a redneck joke, playing off the stereotype that hillbillies bathe once a week on Saturday or Sunday.