Why am I in a race by myself in Rocket Racing?
If you find yourself in a race all by yourself, double-check your Fortnite party settings. If your party is set to private in Fortnite, you will default to private in Rocket Racing. Change the setting to Public so you can race against others!
For how to adjust your party settings, see How do I manage my party, voice chat, and text chat options from the Fortnite Lobby?