What the Five FMCSA BASICs Actually Measure
FMCSA's Safety Measurement System (SMS) organizes roadside inspection results into five categories, known as BASICs — Behavior Analysis and Safety Improvement Categories. Each one tracks a different type of safety risk, and together they're the closest thing to a continuously updated safety scorecard that exists for most carriers, since the vast majority have never gone through a full compliance review (see What a Safety Rating Is — and Why Most Carriers Don't Have One).
1. Unsafe Driving
This category covers violations observed during roadside inspections and reported crashes related to dangerous driving behavior — speeding, reckless or improper lane changes, using a handheld phone while driving, and similar moving violations. Because these violations are typically caught during traffic enforcement rather than a vehicle inspection, this BASIC reflects how a carrier's drivers behave on the road, not the condition of its equipment.
2. Hours-of-Service (HOS) Compliance
Federal hours-of-service rules limit how long a driver can be on duty and driving before taking a required rest break, to reduce fatigue-related crashes. This BASIC tracks violations of those limits — driving beyond the allowed hours, falsifying a logbook or electronic logging device record, or failing to take a required break. It's one of the more heavily scrutinized categories because fatigue is a well-documented contributor to serious crashes.
3. Driver Fitness
This category covers whether drivers are properly licensed and medically qualified to operate a commercial motor vehicle — a valid commercial driver's license (CDL) for the vehicle type, a current medical certification, and compliance with any restrictions on that certification. A violation here usually means a driver was operating without proper credentials on file, not that a crash or moving violation occurred.
4. Controlled Substances/Alcohol
This BASIC tracks violations related to drug and alcohol use and testing — a positive test result, a refusal to test, or operating a commercial vehicle under the influence. Carriers are required to maintain drug and alcohol testing programs for their drivers, and lapses in that program can also surface here, not just an individual driver's violation.
5. Vehicle Maintenance
This is the mechanical-condition category: brake problems, worn tires, lighting defects, steering and suspension issues, and other equipment violations found during a roadside inspection. It's typically the category with the highest overall violation volume, simply because a physical inspection can surface many small defects that individually seem minor but collectively indicate how well a fleet is maintained. See Vehicle Maintenance Violations That Most Often Ground a Truck for the specific defects that come up most.
FMCSA previously tracked a sixth category, Crash Indicator, based on a carrier's reported crash involvement. It's not part of the current public BASIC framework the same way the five above are, though crash history itself remains public and is shown separately on a carrier's profile — see How FMCSA Crash Reporting Works — and Its Known Gaps.
How a BASIC score is built
Each BASIC is calculated from violations found during roadside inspections over a rolling window, generally weighted so that more recent and more severe violations count for more. The result is a measure that reflects a mix of how many inspections a carrier has had and how many violations turned up relative to that exposure — a carrier with very few inspections simply doesn't generate enough data for FMCSA to calculate a reliable score in a given BASIC.
Measure vs. percentile vs. alert
It's worth separating three different things FMCSA's data can show for a BASIC: the raw measure (a calculated value based on violation history), a percentile ranking against peer carriers, and an alert flag indicating the carrier exceeds a threshold FMCSA considers worth flagging. Not every carrier type gets all three published — see How to Read an SMS Percentile for the specifics of what's actually public for property carriers versus passenger/hazmat carriers, and how CarrierPedia fills the gap for the majority that don't get an official percentile.
Where to see a carrier's BASIC results
Use Safety Rating Lookup to check a specific carrier's BASIC results and safety rating status together, or DOT Number Lookup to open its full profile, which also includes inspection counts, out-of-service rates, and crash history alongside the BASIC breakdown.