A method for detecting inland barrier (16, 16′) crossings (24, 26, 30) using speed layers from community input probe traces in combination with a digital map. Inland barrier crossing specifications are detected and/or validated using information about the speed of probes that actually cross the barrier (16, 16′). A bridge (26) across the inland barrier (16) is inferred if the velocity average for barrier crossing probe traces is greater than an established threshold value. Conversely, a ferry (24) is inferred if the average velocity for barrier crossing probe traces is less than the established threshold value. When there is a prominent gap in the data for the barrier crossing probe traces, a tunnel (30) is inferred.