Accepting Per Diem as part of your drivers wages reduces social security benefits and work comp benefits. This is well documented and a thriving practice in the industry. Companies love it because it reduces the social security tax the company pays on the employees behalf (it is required). It makes me crazy to see drivers accept per diem as wages and the companies to have the nerve to actually charge the driver to implement the practice. If you are taking per diem as part of your wages and can opt out, seriously look at the details. Trucking truth and ask the trucker web sites provide good explanations. Trucking companies take advantage of drivers in many ways. this one (in my mind) is unforgivable.