@Tijn looks like someone made a guide for the game. Apparently this game is part of a series in Japan that only had one title make its way over to the US. https://www.roadtripguide.info/
Yesterday I spent most of the day playing Road Trip Adventure, a 2002 open world RPG for Playstation 2, in which all the characters are cars and instead of battles there are races.
This game is great. Fantastic writing and an engaging numbers-go-up type game loop. The world is also absolutely huge and free to explore.