Demand-response transit (DRT) is a non-fixed route, flexible transit service, often referred to as dial-a-ride. DRT provides curb-to-curb or door-to-door pickups and drop-offs upon customers’ request and usually requires advanced scheduling by the customer. Transit agencies choose DRT to flexibly accommodate more people in areas with low population or poor road conditions. DRT is a transit solution when the funding or the external environment cannot support fixed-route transit.