Hey! Big fan of Double Dash and Mario Kart in general. Though I'm not sure why times are based on RTA instead of the in-game time. What are the advantages of RTA?

Hey juicebox! We use RTA in order to make sure that everyone is playing on 60hz and doesn't take breaks between tracks. Because of this we can allow people to submit runs without video verification.

Hey fellow New Jersey resident: to add to what Goomba said, if you are competing for Time Trial times (http://www.mariokart64.com/mkdd/) we only use IGT as opposed to RTA.