One of the ways the SMS accounts for the differences between motor carriers and their operations is by placing carriers in safety event groups based on the number of safety events (e.g., inspections, crashes) in which the carriers have been involved. However, the Federal Motor Carrier Safety Administration’s foremost concern is safety and it accomplishes this by addressing the carriers who pose the greatest crash risk, irrespective of their industry segment.

Safety event groups enable the SMS to deal with the widely diverse motor carrier population, while ensuring that similarly situated carriers are treated with the same standards. Safety event groups do not compare carriers by the commodities they haul or their industry segment.

The tables below outline the safety event groups for each of the Behavior Analysis and Safety Improvement Categories (BASICs) and can be found in the SMS Methodology document.

Hours-of-Service (HOS) Compliance, Driver Fitness, and Vehicle Maintenance BASICs

Safety Event Group Category	Number of Relevant Inspections*
1	3-10 (HOS Compliance) 5-10 (Fitness, Vehicle)
2	11-20
3	21-100
4	101-500
5	501+

Hazardous Materials Compliance BASIC

Safety Event Group Category	Number of Relevant Inspections*
1	5-10
2	11-15
3	16-40
4	41-100
5	101+

*A relevant inspection is one where the roadside inspector reviewed a particular area for evidence of violations (not all inspection types/levels look at all areas).

Controlled Substances/Alcohol BASIC

Safety Event Group Category	Number of Inspections with Controlled Substances/Alcohol Violations
1	1
2	2
3	3
4	4+

The Unsafe Driving and Crash Indicator BASICs divide the safety event groups further into two additional categories: combo and straight segments. The following is used under the SMS to determine the carrier's segment:

• Combo – combination trucks/motor coach buses constituting 70 percent or more of the total Power Units (PUs).
• Straight – straight trucks/other vehicles constituting more than 30 percent of the total PUs.

Unsafe Driving BASIC

Safety Event Group Category	Combo Segment: Number of Inspections with Unsafe Driving Violations	Straight Segment: Number of Inspections with Unsafe Driving Violations
1	3-8	3-4
2	9-21	5-8
3	22-57	9-18
4	58-149	19-49
5	150+	50+

Crash Indicator BASIC

Safety Event Group Category	Combo Segment: Number of Crashes	Straight Segment: Number of Crashes
1	2-3	2
2	4-6	3-4
3	7-16	5-8
4	17-45	9-26
5	46+	27+