 In its initial specifications for a replacement for the M3 medium tank, the U.S. Army restricted the Sherman's height, width, and weight so that it could be transported via typical bridges, roads, railroads and landing craft without special accommodation.Army Regulation 850-15 restricted the widths of a tank to 103 inches and its weight to 30 tons.To conform to these standards the M4's initial tracks were 16.5 inches wide which produced ground pressure of 14 pounds per square inch and limited its off-road mobility.