What Do These Six Crashes Have in Common?

Can you spot the common denominators in these six crashes?

1. Collision of Motorcoach with Combination Vehicles Parked Along Exit Ramp to I-70 Rest Area

At 1:48 a.m. on July 12, 2023, a motorcoach carrying 21 people veered off I-70 near Highland, Illinois, colliding with three parked combination vehicles. Three passengers died. The driver and 11 other passengers sustained injuries of varying severity.

2. Combination Vehicle Rollover, Fire and I-95 Overpass Collapse

At 6:17 a.m. on June 11, 2023, a truck-tractor with a tank trailer carrying 8,500 gallons of gasoline crashed while exiting northbound I-95 in Philadelphia, Pennsylvania. The driver lost control on a curved exit ramp, causing the truck to overturn and strike a concrete barrier. The resulting fire destroyed the truck, caused the collapse of the northbound I-95 lanes and fatally injured the truck driver.

3. Box Truck Centerline Crossover Collision with Bus

At 6 a.m. on Jan. 28, 2023, a bus and a box truck collided head-on on New York State Route 37 in Louisville, New York. The truck crossed the centerline, striking the bus, which was transporting workers to a construction site. This crash resulted in six fatalities, two serious injuries and five minor injuries among the bus passengers, along with minor injuries to the bus driver and serious injuries to the truck driver.

4. Rear-End Collision Between Combination Vehicle and Medium-Size Bus

At 1:36 a.m. on Dec. 16, 2022, a trucktractor with a semitrailer crashed into the rear of a slower-moving bus on I-64 near Williamsburg, Virginia. The truck, traveling between 65 and 70 mph with cruise control, did not brake before impact, while the bus was moving at 20 to 25 mph. The collision resulted in the deaths of three bus occupants, serious injuries to nine bus occupants and the truck driver, and minor injuries to 11 bus occupants.

5. Multivehicle Collision Involving Milk Tank

At 10:07 p.m. on June 9, 2021, a trucktractor with a tank trailer crashed into a queue of stopped passenger vehicles on State Route 202 in Phoenix, Arizona. Traveling at 62 to 64 mph without slowing or steering, the truck initiated a chain-reaction collision involving six other vehicles. The crash resulted in four fatalities and 11 injuries among passenger vehicle occupants, with the truck-tractor and one car consumed by fire.

6. Multivehicle Crash in a Queue of Slowed and Stopped Traffic

At 6:45 a.m. on June 12, 2020, a trucktractor with a semitrailer struck the end of a traffic queue of slowed and stopped vehicles on I-39 near Arlington, Wisconsin, which had formed due to prior collisions. This initiated an eight-vehicle crash that resulted in four fatalities and three serious injuries.

All but one of these crashes occurred in the 2 to 6 a.m. window, the lowest point of a typical circadian rhythm when the body’s drive for sleep is strongest. The exception occurred in the late evening, the typical highest peak of homeostatic sleep pressure, when the body’s timer drive for sleep is strongest.

All crashes involved fatalities, injuries and major damage – main features of fatiguerelated crashes. In fatigue-related crashes, drivers do not brake.

While many drivers may operate at those times without incident, another common factor in these six crashes, revealed only after a thorough National Transportation Safety Board (NTSB) investigation, was an irregular schedule. Check the sources at the end of this article for the NTSB investigation reports on each of these six crashes to learn about the crash specifics, the lessons learned and the NTSB recommendations. These reports are a must-read for motor carrier principals and safety managers.

Adopting regular schedules and sound scheduling practices, as recommended by the North American Fatigue Management Program (NAFMP), is essential for preventing fatigue-related crashes, maintaining driver alertness and enhancing operational efficiency. NAFMP offers a free online course, Module 9: Driver Scheduling and Tools, available at lms.nafmp.org

Additionally, a recording of the June 25 webinar, “The Scheduling Puzzle: Sleep Science and Driver Fatigue,” provides practical applications of sleep science to scheduling and staffing. The webinar is available at nafmp.org/webinars. Anyone involved in driver scheduling must understand how sleep architecture, circadian rhythm, sleep pressure and brain wave speeds affect a driver’s alertness to prevent crashes and maximize productivity.

Understanding the Physiological Roots of Fatigue in Scheduling

Several key physiological factors contribute to driver fatigue, each directly influenced by scheduling decisions:

• Time of Day: The human body's circadian clock naturally promotes alertness during the day and sleep at night. Operating between midnight and 7 a.m. significantly increases fatigue. Schedules requiring extensive night driving counteract this natural rhythm, leading to poorer quality sleep during the day and increased fatigue while driving.
• Recent Sleep: Most individuals need between six and nine hours of sleep for optimal function. Sleep deprivation in the last 24 hours can be a significant fatigue factor. Scheduling practices that consistently reduce sleep time opportunity directly contribute to this deprivation.
• Continuous Hours Awake: Being awake for more than 16 consecutive hours since the last major sleep period dramatically increases fatigue due to homeostatic sleep pressure. Long hauls without adequate breaks for restorative sleep, a common outcome of poorly planned schedules, push drivers into this dangerous zone.
• Cumulative Sleep Debt: Accumulated sleep debt must be repaid. More than eight hours of accumulated sleep debt since the last full night of sleep, including disrupted sleep, is a major fatigue factor. Schedules offering inconsistent rest periods or forcing drivers to constantly "catch up" on sleep contribute to this chronic issue.
• Gradual Schedule Changes: The body's circadian rhythm adapts slowly to changes. When shifting work schedules, do so gradually, ideally by no more than 1-2 hours per week. Drastically altering sleep-wake times overnight can lead to significant desynchronization between the internal clock and the external environment, exacerbating fatigue and impairing performance for several days until the body fully adjusts.
• Forward Schedule Changes are Easier: Due to the build-up of homeostatic sleep pressure, the body generally adapts more easily to a schedule that shifts forward (e.g., going to bed and waking up later) than backward (going to bed and waking up earlier). Shifting forward allows homeostatic sleep pressure to accumulate more, making it easier to fall asleep at a later time. Conversely, trying to shift backward fights against existing sleep pressure, making it harder to fall asleep earlier and potentially leading to accumulated sleep debt.
• Task Monotony or Complexity: The nature of the driving task itself can influence fatigue levels. Highly monotonous driving, such as long stretches on straight highways with little traffic or environmental change, can lead to under-stimulation and boredom, making it easier for drivers to become drowsy. Conversely, overly complex or demanding driving conditions, such as navigating heavy traffic, adverse weather or intricate routes, can increase mental workload and cognitive fatigue, even if the driver isn't physically tired. Both extremes require careful consideration in scheduling and rest planning.
• Underlying Sleep Disorders: Undiagnosed or untreated sleep disorders can significantly contribute to chronic fatigue, even with seemingly adequate sleep opportunities. Conditions such as obstructive sleep apnea, where breathing repeatedly stops and starts during sleep, can severely disrupt sleep quality, leading to excessive daytime sleepiness regardless of time spent in bed. Drivers with unmanaged sleep disorders face a heightened risk of fatigue-related incidents and require proper diagnosis and treatment to ensure road safety. Check out NAFMP’s Module 7: Motor Carrier Sleep Disorders Management at lms.nafmp.org.

Shared Responsibility: A Collaborative Approach in a Fatigue Management Program

Mitigating fatigue in driver schedules is a shared responsibility between management and drivers. Management, planning and dispatch establish a driver's work demands. The driving schedule then determines available sleep opportunities. Key actions for management include:

• Promote a Safety Culture: Foster an environment that encourages drivers to value sufficient sleep and safely manage their fatigue. They should be trained to recognize objective signs of fatigue as a significant physiological risk to safety. If your drivers do not feel comfortable telling you when they are tired, you do not have a safety culture.
• Schedule Predictability: Adopt practices that provide drivers with advanced information about scheduling, allowing them to plan their work and rest schedules. Reliable advanced information on scheduled appointments is crucial for drivers to plan effective sleep and nap opportunities
• Practice Fatigue-Conscious Resource Allocation:
  • Leverage resources to provide drivers with nighttime opportunities to sleep
  • Schedule appointments that favor opportunities for naps
  • Favor sequences of duty periods that maximize time to recover from sleep debt during restart
  • Schedule drivers in line with their natural time-of-day preferences and promote regularity of schedules or advanced notice to aid driver planning
  • Query about fatigue levels when revising assignments

Check NAFMP’s Module 2: Safety Culture and Management Practices for a course on how to implement a fatigue management program that includes both a safety culture and a fatigue risk management system (FRMS) at lms.nafmp.org

Empowering Drivers on the Road

While operational pressures exist, drivers have some control over immediate trip planning to mitigate fatigue. Management should support drivers in:

1. Encouraging planning for sufficient rest stops during long-haul driving

2. Promoting the use of naps to supplement sleep, understanding that any sleep is beneficial, even if nighttime sleep is ideal; longer naps can lead to deep sleep, but drivers should allow time for recovery from sleep inertia, using strategies like light and noise exposure, physical activity and smart caffeine use

3. Emphasizing the importance of keeping sleep times as stable as possible

4. Suggesting a nap prior to an evening departure

5. Drivers are responsible for obtaining adequate sleep on workdays and during recovery periods to manage fatigue; they should follow principles of sleep hygiene and seek treatment for sleep disorders

6. While not a substitute for adequate sleep, strategies like breaks, exercise, smart caffeine use and social interaction can provide short-lived relief from fatigue; drivers should be aware these are temporary measures and not a replacement for proper rest

Have your drivers take NAFMP’s Module 3: Driver Education for a complete guide on these principles, with the knowledge and skills they need to change fatigue-risky behaviors, available at lms.nafmp.org.

Part of Your FRMS Arsenal

Scheduling and routing tools can be valuable assets in managing driver fatigue. These tools are decision-support systems, not decisionmakers, and are based on biomathematical models of fatigue physiology. By evaluating fatigue metrics, scheduling and routing tools can inform the planning of predictable operations. This allows for immediate incorporation of mitigations into the scheduling plan and route, reducing the likelihood of unacceptable fatigue levels.

For operations difficult to schedule in advance, periodic review of actual work schedules using these tools can identify contributing factors to fatigue. Some tools even allow for the incorporation of sleep data collected during operations to refine analysis accuracy. This retrospective approach helps management design customized strategies to mitigate fatigue in day-to-day operations.

Make a Commitment to Your Company's Sustainability

Scheduling practices, often influenced by the demands of a dynamic motor carrier industry, can inadvertently contribute to driver fatigue due to factors like time of day, recent sleep, continuous hours awake and cumulative sleep debt. However, by embracing NAFMP principles, motor carrier safety managers, dispatchers and owners can transform their operations to make them more effective and reliable.

Incorporating regular schedules, promoting predictable work and rest cycles, and utilizing advanced scheduling tools are not just recommendations; they are investments in safety, driver well-being and, ultimately, the long-term sustainability of your motor carrier business. By ensuring fatigue management is a shared responsibility and making it a company value in every scheduling decision, motor carriers can protect their drivers, enhance their safety performance and foster a more resilient and efficient operation long term. Please don’t wait for an NTSB investigation of your company to start managing fatigue.

Reach out for questions or specific fatigue concerns at rodolfo.giacoman@cvsa.org.

NTSB INVESTIGATION REPORTS

1. Collision of Motorcoach with Combination Vehicles Parked Along Exit Ramp to I-70 Rest Area (www.ntsb.gov/investigations/Pages/HWY23MH015.aspx)

2. Combination Vehicle Rollover, Fire and I-95 Overpass Collapse (www.ntsb.gov/investigations/Pages/HWY23FH014.aspx)

3. Box Truck Centerline Crossover Collision with Bus (www.ntsb.gov/investigations/Pages/HWY23FH005.aspx)

4. Rear-End Collision between Combination Vehicle and Medium-Size Bus (www.ntsb.gov/investigations/Pages/HWY23MH004.aspx)

5. Multivehicle Collision Involving a Milk Tank Combination Vehicle and Stopped Traffic Queue (www.ntsb.gov/investigations/Pages/HWY21MH008.aspx)

6. Multivehicle Crash in a Queue of Slowed and Stopped Traffic (https://www.ntsb.gov/investigations/Pages/HWY20FH006.aspx)