Study Conducted to Examine HOS Rules

The commercial driver Hours of Service rules - or HOS rules - were first instituted in 1939 and remained virtually unchanged for nearly 60 years. Recently, new research on sleep patterns, fatigue, and driver safety resulted in these rules being reconsidered. The original HOS rules were finally overhauled in 2003, and the changes were put into effect the following year in 2004.

These revamped rules were changed to better follow the 24-hour circadian schedule. The changes include requirements for longer off-duty periods, reduced daily tours-of-duty, an extra hour of driving time, and a provision that allows drivers to zero out their hours after 34 continuous off-duty hours.

In response to these changes, the Federal Motor Carrier Safety Administration (FMCSA) and the trucking industry performed a study to gauge the effectiveness of the revamped HOS rules. The study was to examine the perceptions of those most directly affected by the changes and determine if they provided positive changes in driver safety and health.


The study aggregated driver injury and collision data taken from 23 fleets representing approximately 100,000 drivers and 10 billion annual vehicle miles of travel. Statistics from 2003 - representing the period before the rule changes - were compared to 2004 findings.

An analysis of the data found that there was a 3.7 percent decrease in the collision rate per million vehicle miles traveled, a 4.8 percent decrease in preventable collision rate, and a 0.8 percent decrease in non-preventable collision rate. Driver injury rate decreased by 12.6 percent, collision injury rate went down by 7.6 percent, and non-collision injury rate dropped 13.7 percent. Furthermore, drivers reported feeling more relaxed, more capable of scheduling their time at home and at work, and less fatigued.


The conclusions reached by the study have found that the 2004 changes in the HOS rules were beneficial to drivers and the trucking industry. Based on these findings, the rules were altered further in 2005 to make an 8-hour sleeper berth time mandatory.

View the summary of the study here.


View additional Trucking Articles here.


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