Shinseki lives in West City with his parents. In Goku's Traffic Safety, he has the visit of his cousin, Suno, who is accompanied by Goku (she met Goku while she was on her way to West City).
When he sees Suno, Shinseki runs into the street to go see her, but he gets almost ran over. Goku saves him by using his Power Pole.
The Traffic Agent Lady shows up to inform the kid to not run into the street, and teaches him and Goku about stoplights and when he should cross the street.
- He bears a resemblance the boy who lost his balloon in the episode "Which Way to Papaya Island?".