They mention the appearance of Lunch and Namu in the Dragon Book, but there are actually lots of recycled character models in this episode:
The tiger Goku fights is the pirate that Kame-sennin, Tenshinhan and Chaozu get the dragonball from during the Piccolo Daimao saga (without the eyepatch).
The truck driver is recycled, but we're not sure from where.
The boy is recycled, but again we don't know from where.
The girl walking in front of Namu is the girl Goku gave money to during his first visit to West City.
The boy's mother is Snow's Mother in DragonBall.
The boy's father is Snow's Father in DragonBall (without the moustache).
Exactly how and when this video was distributed seems to be a complete mystery. However, I think it's safe to assume that it was either aired on TV between shows as a public service announcement, or it was distributed to schools as a safety demonstration video. Judging from the warning at the beginning of the video, it seems more likely that it was distributed to schools.
The special videos "Goku's Traffic Safety" and "Goku's Fire Fighting Regiment" are both very rare productions designed to be educational films. They were both completed in June of 1988.
In "Goku's Traffic Safety", Goku is heading to West City to attend Bulma's birthday party, and on the way he ends up learning the rules for getting through traffic. The movie was for children to watch so it would teach them how to get across a pedestrian crossing. Guest characters include an appearance from Lunch as a policewoman (she had the personality of Normal Lunch, but with the blonde hair), as well as Snow, who was first introduced during the Muscle Tower episodes. In 1 cut Namu appears as a passer-by going across at the pedestrian crossing, Oolong is helping cook with all his might, and you need to check out Yamcha in the frilly apron. For the ending, all the actors seem to be singing a traffic safety parody version of "Makafushigi Adventure!", although it's of pretty strange taste.