The number of hours a truck driver can work in a day is governed by Hours-of-Service (HOS) regulations. These rules, mandated by the Federal Motor Carrier Safety Administration (FMCSA), apply to commercial drivers in the United States. The guidelines are designed to mitigate the risks associated with driver fatigue, a significant factor in commercial motor vehicle accidents. Compliance with these limits is mandatory for carriers and drivers.
The Foundation of Hours-of-Service Rules
The objective of the HOS rules is to manage driver fatigue and promote highway safety. These federal regulations, outlined in 49 CFR Part 395, apply to most commercial motor vehicle (CMV) drivers involved in interstate commerce. Understanding the limits requires distinguishing between two categories of work time: Driving Time and On-Duty Time.
Driving Time is the time a driver spends operating the vehicle while it is moving. On-Duty Time encompasses all work-related activities, including driving, waiting for loading or unloading, performing vehicle inspections, or administrative duties. The HOS framework sets separate maximums for driving time and the total on-duty period.
Defining the Three Core Daily Limits
The daily limits dictate the maximum time spent driving, the total allowable workday, and mandatory rest requirements. A driver must take a minimum of 10 consecutive hours off duty before starting a new shift.
The maximum amount of time a driver can spend driving within a single shift is 11 hours. This 11-hour limit is a cap on time behind the wheel and is calculated from the end of the driver’s last 10-hour rest period. This driving time must occur within the 14-hour driving window.
The 14-Hour Driving Window is the total consecutive time a driver can be on duty, including driving and non-driving tasks. Once the shift begins, the 14-hour clock starts and cannot be paused. When the 14 hours expire, the driver must take 10 consecutive hours off duty, regardless of whether they used all 11 hours of driving time. The final daily rule is the Mandatory 30-Minute Break, which must be taken after a driver has accumulated 8 cumulative hours of driving time.
Cumulative Weekly Driving and On-Duty Limits
Beyond the daily restrictions, HOS rules establish cumulative weekly limits to prevent the buildup of fatigue. These restrictions limit the total number of on-duty hours a driver can accumulate over a set period. The two main cumulative cycles are the 60-Hour Limit and the 70-Hour Limit.
The 60-Hour Limit restricts a driver to a maximum of 60 on-duty hours within a 7-consecutive-day period, applying to carriers that do not operate CMVs every day. The 70-Hour Limit is for carriers that operate daily, allowing a maximum of 70 on-duty hours within an 8-consecutive-day period. On-duty time includes all driving and non-driving work tasks.
To reset either cumulative clock, a driver must take a mandatory 34-Hour Reset. This requires the driver to take a minimum of 34 consecutive hours off duty, after which their weekly clock is fully reset, allowing them to begin a new cycle.
Common Exceptions and Special Provisions
The HOS regulations include specific provisions that allow for flexibility under certain circumstances. These exceptions address common scenarios while prioritizing driver safety.
Short-Haul Exception
The Short-Haul Exception relieves certain drivers from maintaining a detailed Record of Duty Status if they meet specific criteria. This applies to drivers who operate within a 150 air-mile radius of their work location and return there at the end of their shift. They are limited to a 14-hour work shift. Drivers who qualify are exempt from the mandatory 30-minute break rule and do not need to use an Electronic Logging Device.
Adverse Driving Conditions
The Adverse Driving Conditions provision provides flexibility when drivers encounter unexpected delays caused by weather or traffic. If a driver encounters unforeseen conditions, they are allowed to extend both their 11-hour driving limit and their 14-hour driving window by up to two hours. This exception applies only if the conditions were not known, or could not reasonably have been known, by the driver or the motor carrier before the shift began.
Sleeper Berth Provision
For drivers who utilize a sleeper berth in their truck, the Sleeper Berth Provision offers a way to split the required 10 consecutive hours of off-duty time into two segments. This split must involve one period of at least 7 consecutive hours spent in the sleeper berth, and another period of at least 2 consecutive hours, which can be spent either off-duty or in the sleeper berth. Both periods must add up to at least 10 hours. When used correctly, neither period counts against the 14-hour driving window, effectively pausing the clock and providing greater flexibility.
Tracking Hours and Compliance Requirements
To ensure compliance with HOS regulations, most commercial motor vehicles are required to use an Electronic Logging Device (ELD). An ELD is a certified electronic hardware device that synchronizes with the vehicle’s engine to automatically record driving time. This technology replaces traditional paper logbooks, providing a more accurate and tamper-resistant record of a driver’s duty status.
The ELD automatically records data points like engine hours, vehicle movement, and miles driven, making it easier for drivers and carriers to track compliance with the daily and weekly limits. Non-compliance with HOS regulations can result in significant consequences for both the driver and the motor carrier. Drivers face potential fines and can be placed Out-of-Service, prohibiting them from operating the vehicle until they have received the required rest. Motor carriers are also subject to fines and may see a reduction in their safety rating for HOS violations.