It is based on the idea that each validation is encapsulated by a simple, stateless predicate that receives some input and returns either true or false.

“The broader issue is clearing space for your transit to get through congestion, and most of that congestion is from private cars, not [ride-hail],” says Ben Fried, the group’s communications head. “Cities need to make transit fast, affordable, convenient." Truly attractive transit has to do that better than private cars.