A WIM (weigh-in-motion) sensor has an oblong hollow profile and includes two force-transmission plates arranged parallel to each other. A tube is arranged between the plates and is integrally formed with the plates and defines a hollow space. Two supports that are arranged opposite one another are formed inside the hollow space, each support extending away from a respective plate and between which a measuring element is received centrally in the tube under preload. The tube includes two tube segments designed to be mirror-symmetrical with respect to each other, which join the plates together and on the inside adjoin the hollow space. The wall thickness of each tube segment has a relatively thick region between at least two relatively thin regions.