Alphabet’s Waymo autonomous-car unit is preparing to dip its toes into one of the biggest and most challenging ridehailing markets there is: The ride to and from the airport.

Waymo is planning to test service between Phoenix Sky Harbor International Airport and downtown, the company said at a TechCrunch conference last week. Initially, its driverless Jaguar SUVs won’t attempt to hazard the promenades immediately in front of the terminals at the nation’s ninth-busiest airport. Instead, they will serve rail stations at the airport’s perimeter (see map), letting departing passengers take the shuttle from there to begin the trek to the gates.

“Eventually we’ll expand to the terminal,” said Waymo spokesperson Julia Ilina. “Terminal dropoff is a challenging, chaotic thing.”