Traveling this summer? It’s never too soon to start planning your ground transportation.

Getting around on vacation is getting harder than ever. With another car rental shortage forecast for this summer, you might find yourself stranded at your hotel or vacation rental. But there are new ways to solve your ground transportation problems…

Travelers are starting to rethink ground transportation. Stan Caldwell, an associate professor of transportation and public policy at Carnegie Mellon University, says new “mobility as service” platforms are offering travelers more options for getting around.

If you’re traveling to Pittsburgh, consider downloading the Transit app, which partnered with MovePGH to let users combine inexpensive, shared mobility options with the city’s mass transit. “These services include public transportation, bike and scooter share and ride-hail services like Lyft and Uber,” he says.

If you’re headed to Europe, you can download an app called Whim that allows you to access transportation options in places like Antwerp, Belgium; Helsinki; and Vienna.