FreeGameDev

That is, can two players play using the same computer?

we have splitscreen for that in both online and offline

I know you have split screen, but I tried to play hot seat yesterday and I couldn't figure out how to do it. My son got real impatient about it. Maybe you need a tutorial or even a video about how to do it because I could not figure it out. Actually, even better, get some six year olds to try it and if they can't figure it out and get frustrated you know you are doing it wrong.

if you mean something like players take turn racing the track and try to beat the other's time then ghost race mode is probably what you need

Select "Splitscreen Multiplayer" on the menu. (I think that was called just "Multiplayer" on the build on my arcade machine.) Add the second person in by pressing the appropriate button for the controls. The big thing is that you need to configure a second set of controls before you go to "Splitscreen Multiplayer". Did you do that?