Do I need MCS-150 if I only operate intrastate?
Most intrastate carriers with a USDOT still need to file MCS-150 every 24 months. The 49 CFR §390.19 biennial-update requirement applies to any carrier registered with FMCSA — intrastate-only carriers who hold a USDOT (typically because they operate CMVs above the federal threshold and the state-level USDOT registration was federalized) are in scope.
About 30 states have adopted the federal USDOT registration system for intrastate CMV operations as well — a CMV operating intrastate above the federal threshold (10,001 lbs+ for some classifications, 26,001 lbs for CDL) gets a USDOT and is then on the FMCSA biennial-update schedule. The carrier files MCS-150 the same as an interstate carrier.
The remaining states maintain a separate state-level intrastate registration system. Carriers operating purely intrastate in those states may not have a federal USDOT and therefore not be on the MCS-150 schedule — but they typically have a state-level equivalent registration with its own update cadence.
For carriers operating both interstate and intrastate (a common pattern for regional fleets), the federal MCS-150 covers the interstate operation; the intrastate registration cycle is a separate state-level filing on top.
A common confusion: a carrier with a USDOT but no MC (private fleet hauling its own goods, intrastate-only) still needs MCS-150 because they hold an active USDOT. The MC vs USDOT distinction does not change the §390.19 requirement.