Frequently Asked Questions
The Frequently Asked Questions (FAQs) are questions and answers about Compliance,
Safety, Accountability (CSA) that the Federal Motor Carrier Safety Administration
(FMCSA) compiled to assist the public. As questions come in through the website,
FMCSA adds them to the database along with their answers. If you do not see your
question or topic addressed, please
contact us
by submitting a feedback form. We will respond to you directly and consider your
question for inclusion in the FAQs.
The FAQ area has recently been enhanced. Users can now search FAQs by stakeholder
group, topics (displayed on the left side of the page), or by entering a keyword
below. Choosing “Show All” will display the entire collection of FAQs.
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Why does the Safety Measurement System (SMS) use segmentation and how does it work?
Answer
The SMS uses segmentation within the Unsafe Driving and Crash Indicator Behavior
Analysis and Safety Improvement Categories (BASICs) to account for carrier differences
by placing the carrier population into two groups based on the types of vehicles
operated. Carriers are grouped by the following two vehicle types/operations:
- Combo Segment — Combination trucks/motor coach buses constituting 70 percent or
more of the total Power Units (PUs) (vehicles).
- Straight Segment — Straight trucks/other vehicles constituting more than 30 percent
of the total PUs (vehicles).
The segmentation of motor carriers means that companies who have fundamentally different
types of vehicles/operations are not compared to each other.
For a detailed description and examples of the safety event groupings by and for
each BASIC, please refer to the
SMS Methodology document.
(
link)