This paper presents field measurements of the rotation-al stiffness of three transport vehicles equipped with different types of suspensions: leaf, combined air and leaf, and hydraulic suspensions. The rotational stiffness was determined by measuring the tilts of the vehicles when a girder or known weights were placed on them at various eccentricities. One of the tested vehicles, which featured transversely expandable wheel spac-ings varying from 6 to 18 ft (1.8 to 5.5 m), exhibited an increase in rotational stiffness from 78,181 to 134,584 kip-in./radian (8833 to 15,206 kN-m/radian). This paper summarizes the rotational stiffness for all the vehicles tested by the authors. The field measure-ments conducted have enriched the existing database on vehicle rotational stiffness in the United States
