The von Kármán–Gabrielli diagram (also Gabrielli–von Kármán diagram, GvK diagram) is a diagram which compares the efficiency of transportation methods by plotting specific tractive force, or specific resistance (ε = P/mgv = E/mgd) against velocity (v). It was first used by Theodore von Kármán and Giuseppe Gabrielli in their 1950 paper on this subject. The basic idea is that formally, 1 kWh/100 km has the dimensional units of a force, a resistance force amounting to 36 N.