49 CFR Part 387.7 states that "Form MCS 90" is an "Endorsement for Motor Carrier Policies of Insurance for Public Liability Under Sections 29 and 30 of the Motor Carrier Act of 1980." While it may appear to be an insurance certificate, in reality it is more. It is an endorsement that shows proof of required financial responsibility, and all vehicles operated by for-hire carriers must have an MCS 90. In the US, motor carriers domiciled in contiguous foreign countries (Canadian carriers) must have a legible copy, in English, on board the vehicle while US carriers must have the form at their principle place of business. Be aware though, some Canadian carriers are leased onto and operating under the authority of a US carrier when operating in this country and thus would not need the form in the vehicle.
