How the hours of service rules for truck drivers ever became a safety regulation is a question that has vexed many in the industry. The rules came into being in the 1930s as a combination of labor and economic regulation intended to bring some stability to the nascent trucking industry, and to protect workers from overly demanding employers. There were few rules to speak of at the time, and little was known scientifically about fatigue, sleep, driver performance, or crash causation.

The earliest regulations requiring rest for truck drivers, circa 1935, allowed drivers to work 12 hours within a 15-hour period while requiring nine hours of rest and three hours of breaks within a 24-hour day. That rule also established a weekly maximum of 60 hours on-duty over seven consecutive days. Sound familiar?

A few years later, organized labor petitioned trucking’s regulator, the Interstate Commerce Commission, for a reduction in the hours drivers were required to work, proposing an eight-hour daily limit and 48-hour weekly limit. The ICC, lacking any specific knowledge on the matter, asked the U.S. Public Health Service in 1938 to investigate truck driver hours of work. The resulting report was not very conclusive, but it did note, “... a reasonable limitation of the HOS would ... act in the interest of highway safety.”

The rules would not change substantially until 1962, when the ICC eliminated the 24-hour framework and replaced it with a rotation that allowed the driver to drive up to 10 hours within a 15-hour period before being required to take eight hours off. The net effect allowed the work/sleep rotation to slip to as short as 16 hours. This meant drivers could get across the country in fewer days, but they would find themselves with no hours left in their 60-hour, seven-day cycles within five or six days.

The split sleeper-berth provision was added in the mid-1960s, which allowed drivers to split their sleeper time into two periods. This meant some would log formerly “clock-running” on-duty time as sleeper time, regardless of whether they were in the sleeper resting or not.

By the late 1960s, as highways grew more crowded, the number of truck crashes was rising, and several safety groups began calling on government to do something to prevent the carnage. They claimed truck driver fatigue was at the root of many crashes and called for changes to the drivers’ HOS rules. This prompted the first scientific analysis of driver fatigue. Three studies would be conducted in the 1970s that did note a causal relationship between fatigue and truck crashes, but the results were not conclusive enough to justify changes proposed in 1979 by the U.S. Department of Transportation.

The HOS rules would remain fundamentally unchanged for almost 60 years until 1995, when Congress directed the DOT to establish a new set of HOS rules incorporating the latest scientific understanding of human fatigue and alertness. DOT published a new rule in 2003 that, again, merely tweaked the rule.

Those, and subsequent changes to HOS up to the present, have statistically done little to lower truck crash rates. While many in the industry complain that they did succeed in limiting trucking’s productivity and drivers’ ability to rest when they needed to rest, critics say the rule changes have not addressed the suspected problem of truck driver fatigue as it relates to crashes and to driver well-being.

Depending on which of the fatigue experts you believe, the various HOS rules developed over the past 80 years have increased driver fatigue while limiting opportunities for rest, have increased drivers’ alertness but could still be improved upon to reduce crashes, or, have done little to meaningfully reduce truck crash rates.