According to JJ Keller, hours of service violations and brake problems were the top violations found during the  2007 Roadcheck. Between vehicle problems, and driver problems, approximately 49% of the inspections showed either the vehicle or the driver should not be on the road. JJ Keller reported:

A total of 62,370 inspections were conducted during the 72-hour Roadcheck 2007 event from June 5–7, 2007. The following out-of-service (O-O-S) statistics emerged for drivers and vehicles:

Driver O-O-S Violations

Violation

Number

Percentage

HOS

3,027

65.9%

False Logs

  522

11.4%

Suspended

  177

3.9%

Driver Qualification

  166

3.6%

Endorsement

  120

2.6%

Expired License

   78

1.7%

Drugs/Alcohol

   71

1.5%

Age

   15

0.3%

Revoked License

   12

0.3%

Withdrawn License

   11

0.2%

Cancelled License

    9

0.2%

Other

  607

13.2%

TOTAL

4,815

Vehicle O-O-S Violations

Violation

Number

Percentage

Brake Adjustment

 6,954

27.7%

Brake System

 6,566

26.2%

Lights

 3,521

14.0%

Loading (securement)

 2,610

10.4%

Tires and wheels

 2,286

9.1%

Suspension

 1,159

4.6%

Steering

   533

2.1%

Frame

   345

1.4%

Hazardous materials

   261

1.0%

Coupling device

   178

0.7%

Fuel system

   166

0.7%

Exhaust

    48

0.2%

Other

   924

3.7%

TOTAL

25,551

The number of U.S. state inspections totaled 53,451 (85.70%); Canadian inspections totaled 7,274 (11.66%); U.S. FMCSA inspections totaled 1,506 (2.41%); and Mexican inspections totaled 139 (0.22%).

See: www.jjkeller.com/news/newsinfo/T_news2194.htm