Skylanders has always offered very good backwards compatibility for all the toys in the series, and almost everything old is usable with newer games. But this doesn't include the Nintendo Switch version of Skylanders Imaginators, which won't have any support for either vehicles or traps. This likely also means there won't be a racing mode either. The press release reads:
"In March 2017, Skylanders Imaginators makes its way to Nintendo Switch, offering players a new way to play. No Portal of Power®? No problem with Skylanders Imaginators on the Nintendo Switch as the platform introduces a digital library that allows players to easily load and store their 300+ toys from the Skylanders® franchise* directly to the new home gaming system.
*Excludes Traps and vehicles, which are not playable in the Nintendo Switch version of the game."
Skylanders Imaginators is out on, well, all the consoles, and it's also going to be a Switch launch title come March 3.