A 34-mile highway extending from Tarpon Springs to St. Petersburg, US 19 is the most heavily traveled arterial road in Pinellas County. It is part of the Florida Strategic Intermodal System (SIS), a statewide network of high-priority transportation facilities, and is served by Route 19, which has the highest ridership of all routes in the Pinellas Suncoast Transit Authority (PSTA) system.
Since the 1980s, substantial public investment has converted US 19 from an at-grade arterial road to an uninterrupted partially controlled access facility, including overpasses and interchanges, from 49th Street in Pinellas Park to SR 580 in Clearwater. The MPO Long Range Transportation Plan calls for these improvements to continue north of SR 580 to the Pinellas/Pasco County Line.