At the NTSB, we’ve investigated many tragic transportation accidents that could have been prevented with some planning, forethought, and good decision making. As we mark the beginning of the holiday travel season, we want to encourage all Americans to make it their goal to arrive safely at their destinations, so we’ve boiled down some lessons we’ve learned that the traveling public can use.
Fatigue, impairment by alcohol and other drugs, and distraction continue to play major roles in highway crashes. Here’s what you can do:
If your holiday celebrations involve alcohol, ask a friend or family member to be your designated driver, or call a taxi or ridesharing service.
In a crash, seat belts (and proper child restraints) are your best protection. Always make sure that you and all your passengers are buckled up or buckled in!
Don’t take or make calls while driving, even using a hands-free device. Set your navigation system before you start driving. If you’re traveling with others, ask them to navigate.
By Bus or Train
The NTSB has made recommendations to improve passenger rail and motorcoach operations and vehicle crashworthiness, but travelers should know what to do in an emergency.
Pay attention to safety briefings and know where the nearest emergency exit is. If it’s a window or roof hatch, make sure you know how to use it.
If you’re unsure of where the exits are or how to use them, or if you didn’t receive a safety briefing, ask your driver or the train conductor to brief you.
Always use restraints when they’re available!
By Air or Sea
Airline and water travel have become incredibly safe, but these tips can help keep you and your loved ones safe in an emergency.
When flying, make sure that you and your traveling companions have your own seats—even children under age 2.
Don’t forget your child’s car seat. The label will usually tell you whether your child car seat is certified for airplane use; the owner’s manual always has this information.
If you don’t know the rules for using a child’s car seat on your flight, call the airline and ask what you need to know.
Pay close attention to the safety briefing! Airline and marine accidents have become very rare, but you and your family can be safer by being prepared.
Whether you’re on an airplane or a boat, know where to find the nearest flotation device.
No matter how you travel, you deserve the benefits of the lessons we’ve learned through our investigations, but you need to play an active part to take advantage of them. This holiday season, make a commitment to put safety first.
I recently had the privilege of speaking in Manchester, England, at the National Safer Roads Partnerships Conference. The United Kingdom has some of the lowest road-user fatality rates in the world. While our annual vehicle miles traveled vary greatly, on a typical day, about 109 road users are killed on America’s roadways, while only 5 Britons lose their lives the same way. But, as I reminded the conference audience, even one fatality is still too many.
This was a unique opportunity to represent the NTSB because the audience was mainly British law enforcement officers, and the British tradition of “policing by consent” was tailor‑made for a prevention-focused discussion. Policing by consent means that, because most people want law and order, the goal should be to prevent crime rather than focus on punishing perpetrators. Our Safety Advocacy Division operates with much the same philosophy, working to prevent transportation accidents by encouraging stakeholders to implement the agency’s recommendations. We also explain road safety to vulnerable populations, such as young drivers, to bring lifesaving information to the traveling public, and we share our findings with colleagues.
We know that, as we face coming challenges in road safety, prevention opportunities abound. Our recent speeding study noted the value of a “safe system” approach, which depends on layers of safety in a given road environment and recognizes preventive uses of technology, such as automated speed enforcement. Our recent investigation into the fatal crash of a partially automated vehicle allowed us to consider the double-edged sword of automation. Our investigations have shown that, as vehicles rely more and more on automated sensors, they also collect more data, which should be gathered in a standard format and reported when vehicles with enabled control systems crash.
The world is changing, crash factors are changing, and our tools are changing. The data that cars themselves can provide about crashes is expanding. As I told the law enforcement officers in Manchester, the NTSB has learned that everything an accident can tell us is worth our attention. We are conscious that every safety lesson learned is worth retelling, both to spur acceptance of our recommendations and to prepare ourselves, our colleagues, and the public for the challenges of a fast-approaching future. By sharing lessons learned across borders, we improve our chances at reaching zero transportation fatalities worldwide.
Nicholas Worrell is Chief of the NTSB Safety Advocacy Division.
The Tremont Street Subway in Boston began service in 1897 as the first subway tunnel in North America. That subway tunnel was the beginning of the now complex rail transit system that is commonly known as the Massachusetts Bay Transportation Authority (MBTA), or “the T.” With an average of 1.3 million passengers riding its heavy rail, light rail, trolleys, buses, and ferryboats each weekday, this is one of the busiest transit systems in the country.
I recently had the opportunity to tour the MBTA system and learn how such a complex legacy system is managed. I also heard about the collaboration that has developed between the MBTA and its safety oversight body—the Massachusetts Department of Public Utilities (MDPU). I often used the T years ago when I was in law school, so it was very informative to see how the system has grown and changed in the intervening years.
Improve Rail Transit Safety Oversight is on the NTSB’s Most Wanted List of transportation safety improvements to promote our recommendations addressing oversight of rail mass transit operations. It is critically important that rail transit systems be adequately monitored to maintain and enhance safety and to help ensure that small problems can be caught before they become big ones; our accident investigations have shown that an important part of that monitoring is effective safety oversight. This visit to the MBTA allowed us to observe some of those safety programs and their oversight.
Massachusetts is one of four states (the others being California, Colorado, and New York) that has the authority to compel a rail transit agency to comply with system safety program plans, Federal Transit Administration requirements, and state regulations or requirements. This authority has fostered a collaborative relationship between the MBTA and the MDPU for rail transit safety oversight. These two agencies are in regular contact about rail transit decisions; this open relationship enables faster resolution when issues arise and comprehensive planning to help prevent disasters from occurring.
It was very interesting to see the behind-the-scenes operations that keep everything running smoothly. We received comprehensive briefings from both the MDPU and the MBTA to better understand the system’s history, past and current safety challenges that the agencies face, and plans to improve safety systems and extend the service to serve more of the traveling public in the Boston area.
We also toured the MBTA Emergency Operations Control Center and learned how transportation and law enforcement officials work closely during major planned events, such as the Boston Marathon, the St. Patrick’s Day Parade, and the fireworks displays on July 4, and during unplanned emergencies, like weather events or disasters, to safely move as many people as possible under unusual circumstances.
Our MBTA guides took us underground to the new Emergency Training Center, built in former streetcar tunnels, to see where all MBTA operators, first responders, and law enforcement personnel receive emergency simulation training on heavy rail, light rail, and bus equipment and facilities.
Vehicle and equipment maintenance and upkeep are also part of good safety oversight and are needed to spot any actual or potential problems that may arise, diagnose them, and determine and implement a solution to keep everything running smoothly. To get some idea of that part of the operation, we toured the Orient Heights Car House and learned about the preventative maintenance program that helps ensure all cars are operating efficiently and safely.
On the second day of our tour, we rode the Green Line to get an in-depth look at this oldest subway line in the country. MBTA and MDPU personnel shared their progress toward implementing Positive Train Control—another item on our Most Wanted List—on this line, whose age, signal system, and street‑running sections present operational complexities and risks that the MBTA’s safety programs and oversight continuously seek to address.
The MBTA and the MDPU share the goal of providing and maintaining a reliable, safe transit structure to move the people of Boston safely and efficiently. We enjoyed and appreciated the opportunity to visit and learn so much about this legacy system. In the coming years, we plan to reach out to other mass transit operators and their regulators to learn, first hand, what they are doing to build safer systems and prevent future accidents, injuries, and fatalities.
On August 21, 2006, I was sworn in as the 37th member of the National Transportation Safety Board. At the same time, I was appointed by President George W. Bush to serve as NTSB Vice Chairman. In 2011, President Barack Obama reappointed me for an additional five-year term as a board member.
As I reflect on 10 years as an NTSB board member, there are several things that stand out. First, is the mission. Our role in transportation safety quickly became apparent when, on my seventh day on the job, I launched to an airline crash in Lexington, Kentucky. Tragically, that crash claimed 49 lives.
But, the NTSB’s primary mission involves more than just investigating accidents. It also involves determining the cause of accidents, and then, most importantly, issuing safety recommendations to prevent future accidents. At the entrance to our training center, we have an etched glass window that says, “From tragedy we draw knowledge to protect the safety of us all.” And that’s exactly what we do – we learn from tragedy so we can keep it from happening again.
Recently, one of our investigators wrote to me about a rail accident he investigated where fire and explosion claimed multiple lives. He told of meeting a man who was glaring at the carnage as he pushed a baby in a carriage. As it turned out, the man’s wife – the baby’s mother – had been killed in the disaster. Our investigator promised the man that the NTSB would get to the bottom of why this event occurred so other accidents could be prevented. “I also watched a man standing outside of the exclusion zone peering over the barrier in tears as a backhoe demolished his home,” the investigator explained in his note to me. “My thoughts were of those victims, and it was clear that we were being called upon to do this for them.”
Yes, we are here to give a voice to those who don’t have a voice—the victims and their families of transportation accidents. I take great solace knowing our work really does make a difference and keeps others from enduring similar tragedies.
The NTSB is an independent federal agency – meaning, we are not attached to a larger federal organization such as the U.S. Department of Transportation. In my opinion, independence is one of our greatest virtues because it allows the agency to conduct investigations and explore safety issues without being encumbered by actual or perceived political pressures. As I’ve often said, our independence allows us to “call it the way we see it.”
What also stands out to me is the dedication of the men and women of the NTSB. Their passion and determination to find the truth is uplifting. In the most recent employee viewpoint survey, 96 percent of respondents replied positively to the statement, “When needed I am willing to put in the extra effort to get a job done.” That demonstrates the commitment and dedication NTSB employees share for fulfilling our mission.
In addition to investigative activities, there is a proactive side to the NTSB. Our staff conducts safety studies, tracks and follows up on our safety recommendations, and advocates for safety improvements by providing testimony on safety issues, promoting our Most Wanted List, bringing important safety issues into the public discussion via social media efforts, and organizing safety events such as roundtable discussions.
One of the NTSB’s values is transparency; we are open and honest with the public about our work. We post on our website all accident reports and publications, as well as the docket for each accident. The docket provides reams of background information for accidents, such as interviews, photos, and technical information that may not be in the actual accident report. Our board meetings are webcast and open to the public. And, our Office of Safety Recommendations and Communications ensures the media are informed of the status of investigations by answering questions, arranging interviews, issuing press releases, and releasing updates through social media.
Many are surprised to learn that the NTSB also serves as a court of appeals for pilots, aircraft mechanics, and mariners who receive violation notices from the Federal Aviation Administration and U.S Coast Guard. The NTSB’s Office of Administrative Law Judges (ALJ) processes those cases, and our three ALJs hold hearings to adjudicate those matters.
The NTSB’s Office of Transportation Disaster Assistance – a highly trained group with expertise in social services, emergency management, and forensics – works closely with various organizations to meet the needs of disaster victims and their families. This group also serves as the primary point of contact for family members and disaster victims, providing updates regarding the status of NTSB investigations and addressing their questions. It takes a special person to do the work they do, and I’m always appreciative of how well they do it.
There are other parts of the agency that aren’t often acknowledged, but nevertheless are important to allowing the agency to function. As in any organization, job openings need to be posted and filled, bills paid, contracts written and executed, and our computers maintained. The employees who perform these functions are as dedicated as those performing the agency’s core mission.
To put it simply, I’m so proud to be part of this agency. Our mission, independence, transparency, and people are all so important. I’m honored to have served with them for the past 10 years.
In last week’s blog, Roundtable Review-Part 1, I provided an overview of the NTSB’s July 13, 2016, rail tank car roundtable. Today’s blog discusses how the industry is monitoring its progress and the available options for meeting the earliest federal deadlines.
Following the February 2015 crude oil derailment and fire near Mt. Carbon, WV, the NTSB issued an urgent recommendation calling for the Department of Transportation to make a “publicly available reporting mechanism that reports at least annually, progress on retrofitting and replacing tank cars.” Section 7308 of the FAST (Fixing America’s Surface Transportation) Act calls for the DOT Secretary to implement a reporting mechanism to monitor industry-wide progress toward meeting these federally-imposed deadlines. Many who participated in the roundtable were optimistic that the deadlines could be met.
More than two dozen rail tank car owners, operators, and manufacturers, as well as labor union representatives and transportation safety associations, came together to discuss ways industry and government can work together to overcome the challenges associated with meeting federally-imposed mandates that involve phasing out both legacy DOT-111 and CPC-1232 tank cars that carry flammable liquids (see image of timetable).
Participants addressed concerns with issues surrounding replacing older specification tank cars. “The one thing is to make sure we’ve got the best inspection and prevention techniques and technologies that we can possibly deploy,” said Hal Gard.
Gard is the rail administrator with Oregon’s DOT, a state which saw 42,000 gallons of crude oil spill along a scenic stretch along its revered Columbia River in Mosier after a derailment of CPC-1232 tank cars in June. “It was a bad day,” Gard said. “The CPC-1232s actually performed well, [but] we still are going to have to deal with the aftermath of that accident for a while.”
During the meeting, the roundtable participants dug into various details of and challenges associated with implementing the provisions of the FAST Act—for example, addressing differences between the types of tank cars currently in crude oil and ethanol service, specifications of the new DOT-117 cars, and various options available to the industry to retrofit.
Most agreed that it would take a sustained, concerted effort from all industry parties working together to meet the required deadlines. The shipper is responsible for the proper packaging of whatever they’re going to ship, reminded Robert Hulick, executive vice president with Trinity Rail. He said that many play a role in meeting deadlines, including the tank car owners and those who lease the cars. “It’s not any one party that makes that decision unilaterally,” he said.
Denford Jaja, with the Hess Corporation, agreed that there needs to be “a joint effort between the industry, the shippers, railroads, [and] the regulatory bodies.”
Jaja also said that when all parties involved have access to clear, validated information, it is easier to measure progress toward the goal. “We are fully supportive of a science- and fact-based approach to safety,” he said. “The faster we can resolve uncertainties, I think that’ll give us some certainty on the path forward.”
Andreas Aeppli, principal with Cambridge Systematics, said everyone who has a vested interest or role in the transport of commodities by rail needs to continue to educate themselves and understand what is actually required. For instance, while some of the most distant federal deadlines for halting the transport of crude oil and ethanol in DOT-111 and CPC-1232 tank cars aren’t until May 2025, the earliest mandates for some tank cars take effect much sooner, on January 1, 2018.
“It’s really important to have…information available because it’s freely out there. When you want to hold people’s feet to the fire, particularly as we get closer to the deadlines, [we need] to ensure that everybody is aware of what’s going on and adheres to the regulations and requirements that are being called for,” Aeppli said.
As stated in last week’s blog, those participating in the roundtable left feeling hopeful that progress would continue to be made. William Bates, a labor union legislative director with SMART Transportation Division, was among those who are cautiously optimistic. Addressing the entire roundtable, he said: “I would have the peace of mind knowing that I got the best equipment there. I hope that every car I pull is a [DOT] -117 or [one that has been] retrofitted. We need everybody’s help. Let’s get on the ball!”
For a complete transcript of the roundtable, see our “Events” page.
I had the privilege of moderating a day-long NTSB roundtable pertaining torail tank car safety on July 13, 2016, in which more than two dozen rail-car manufacturers and owners, union representatives, and transportation safety associations discussed the rail industry’s progress and challenges on implementing new federal safety standards for tank cars that carry flammable liquids. The event provided rail industry leaders an open forum to discuss the logistics of replacing the existing tank car fleet in flammable liquid service to meet new federally imposed deadlines, and to identify ways in which government and industry can overcome roadblocks they face to meeting those mandates.
The U.S Department of Transportation (DOT) is requiring shippers to address the oldest, higher risk tank cars first: DOT-111 tank cars – which historically have been the most common type of cars to carry crude oil and ethanol. Shippers using legacy DOT-111 tank cars to haul crude oil must decide to either retire or retrofit them to new standards by March 2018, at the latest. For the DOT-111 tank cars that haul ethanol, shippers have until May 2023.
The deadlines set by federal officials for compliance are more relaxed for newer, modified version of these tank cars, called CPC-1232s. Deadlines to get CPC-1232s out of service for shipping crude oil and ethanol (or retrofitted to meet DOT-117 standards) extend as far into the future as May 2025. For shipping other Class 3 flammable liquids, shippers have until May 2029.
DOT-117 tank cars are a safer means of transporting flammable liquids because these tank cars are less likely experience a puncture (and therefore, a product release) because of several safety specifications that DOT-111 and CPC-1232 tank cars do not have.
Newly manufactured DOT-117 tank cars are built with a thicker shell that is nine-sixteenths of an inch thick, which is 28 percent thicker than legacy DOT-111 tank cars and most CPS-1232 cars. DOT-117 cars also have thermal and top fittings protection; an extra layer of 11 gauge (approximately 3 mm) steel surrounding the shell, known as a tank jacket; and full-height head shields, which add an extra one-half inch of protective steel on each end of the tank cars. Also, there is improved protection to the bottom outlet valve handle to guard against inadvertent opening during a derailment.
Two main points are relevant when considering whether shippers can meet these new deadlines. First, can tank car manufacturers supply enough cars to meet demand? We were encouraged to hear that manufacturers felt they could.
There are, however, more complex considerations on the demand side. With the recent decrease in domestic oil production, some in the industry see steep price tags for new and retrofitted cars as being prohibitive. “This is a game changer for shippers,” said Gabe Claypool, with Dakota Plains Holdings, Inc., during the roundtable.
John Bryne, of the Railway Supply Institute, agreed. He said economic factors heavily influence the decision making process when it comes to the timing of the legacy tank car phase out. “Industry has done a good job at meeting voluntary improvements for better packaging, but more needs to be done. Also, there needs to be some sort of incentive for the shippers to act more quickly.”
Without those incentives, Bryne warned that progress toward swifter compliance with federal deadlines could be stifled, although the deadlines themselves can be met. This leads to the next point: one hurdle toward quick implementation of these needed changes are, in a sense, the deadlines themselves. With some of the due dates extending nine years or more, shippers and those who currently lease tank cars can wait several more years before the recommendations to phase out older tank cars become absolute law.
While these considerations may make sense from a business perspective, from the NTSB’s perspective, the sooner these changes are made, the better – a belief that is fueled by numerous accidents we have seen involving breached tank cars. In the past decade, there have been 28 significant accidents in the U.S. and Canada involving flammable liquids transported by rail, in which nearly 5 million gallons of crude oil and ethanol have spilled. In each of these accidents, legacy DOT-111 or CPC-1232 tank cars were used to transport flammable liquids. If past performance is a predictor of future performance, continuing to transport crude oil and ethanol in DOT-111 or CPC 1232 tank cars poses an unacceptable public risk.
Several roundtable participants expressed optimism that the deadlines could be met.
Robert Fronczak, assistant vice president of the American Association of Railroads, provided statistics showing the number of legacy DOT-111 tank cars in crude oil transportation has steadily decreased since 2013 – from a peak of more than 21,600 three years ago, to just 708 through the first quarter of this year.
Kevin Neels, Ph.D., a transportation and research consultant with The Brattle Group, stated those numbers are a sign industry is headed in the right direction. “A lot of the riskiest cars are going out of service. And that’s good. We need to continue to monitor this to ensure that risk-prone tank cars stay out of service. In due course, we’ll see a much safer fleet hauling these materials.”
In next week’s blog, we will discuss how the industry is monitoring its progress and the available options for meeting the earliest federal deadlines.
The rail business is an industry full of tired, stressed workers. It is an epidemic.
I know this first-hand because, before coming to the NTSB several years ago, I spent more than 30 years working in the freight railroad industry. While freight railroad managers and crews count on reliable schedules to make their shipments and make their customers happy, there is no routine schedule for the hundreds of thousands of crewmembers employed in this business. As a result, many railroad workers are literally walking and working in their sleep.
I was one of them.
One of my last jobs before coming to the NTSB was as a trainmaster for a major freight railroad. My duties included safely seeing the arrival and departure of trains in and out of terminals in California. I spent a large majority of my time reviewing train schedules and communicating with train personnel of arriving and departing trains. I coordinated the efforts of nearly 300 crewmembers, including yardmasters, dispatchers and engineers, to execute the transportation plan on my territory. Additionally, I was responsible for making sure all the work was done safely and in accordance with rules and regulations.
The job was very stressful and required long hours. It wasn’t unusual for me to work 80 hours a week. I often worked overnight, evenings, weekends and long hours.
Over time, I became chronically fatigued. I gained weight and began to lose my memory and other cognitive abilities. I had no routine schedule for sleep, because I worked irregular hours that were counter to my circadian rhythms. Eventually, I began to make mistakes at work and in my personal life – potentially dangerous ones.
Noting how my work and home life was suffering, I went to a sleep specialist. The doctor determined that I was fatigued at a dangerous level – to the point where the state of California took my driver’s license. Ironically, while I could no longer drive a car, I was still expected to carry out the meticulous details associated with managing rail yards.
I warned my bosses, but there was little help or response. I made suggestions for improvements, including encouraging the railroad to provide better lineups and opportunities for rest, but I felt unsupported and became concerned for the safety of my crews. Eventually, I left the railroad and began a new career.
My story is not unusual. And when I came to the NTSB as Chief of the Railroad Division, I quickly learned that the NTSB also realized the dangers of fatigue in the railroad business. As a result of our investigations in recent years, we have issued more than 25 recommendations related to managing fatigue—all still open, needing to be addressed.
One accident, in particular, involving a freight train perhaps best highlights the danger the NTSB is attempting to eradicate. In April 2011, an eastbound BNSF Railway (BNSF) coal train traveling about 23 mph, collided with the rear end of a standing BNSF maintenance-of-way equipment train near Red Oak, Iowa. The collision resulted in the derailment of 2 locomotives and 12 cars. The lead locomotive’s modular crew cab was detached, partially crushed, and involved in a subsequent diesel fuel fire. Both crewmembers on the striking train were fatally injured.
We determined that the probable cause of the accident was the failure of the crew of the striking train to comply with the signal indication requiring them to operate in accordance with restricted speed requirements and stop short of the standing train because they had fallen asleepdue to fatigue resulting from their irregular work schedules and their medical conditions.
As a result of that accident, we recommended that the railway require all employees and managers who perform or supervise safety-critical tasks to complete fatigue training on an annual basis and document when they have received this training, and that they medically screen employees in safety-sensitive positions for sleep apnea and other sleep disorders.
Both the conductor and the engineer had worked irregular schedules for several weeks leading up to the accident. During this time, work start times often varied significantly from day to day for both crewmembers. Changing work start and end times can make achieving adequate sleep more difficult, because irregular work schedules tend to disrupt a person’s normal circadian rhythms and sleep patterns, which in turn can lead to chronic fatigue.
More recently, we investigated an accident in New York where a Metro North Railroad locomotive engineer was operating a train with undiagnosed severe obstructive sleep apnea (OSA). The train, on its way toward Grand Central Station in New York, New York, had 115 passengers on board. The engineer headed into a curve with a 30 mph speed limit traveling at 82 mph, resulting in a derailment. Sixty-one people were injured, and 4 passengers died.
The engineer experienced a dramatic work schedule change less than 2 weeks before the accident, with his wake/sleep cycle shifting about 12 hours. Previously, he had complained of fatigue but had not been tested or treated for sleep apnea. After the accident he had a sleep evaluation that identified excessive daytime sleepiness and underwent a sleep study resulting in a diagnosis of severe OSA. Following the study, he was treated successfully for OSA within 30 days of the diagnosis.
The NTSB issued safety recommendation to the Metro-North Railroad to revise its medical protocols for employees in safety-sensitive positions to include specific protocols on sleep disorders, including OSA.
We have issued numerous recommendations to the Federal Railroad Administration, as well, requiring it to develop medical certification regulations for employees in safety-sensitive positions that include, at a minimum, a complete medical history that includes specific screening for sleep apnea and other sleep disorders, a review of current medications, and a thorough physical exam. If such a recommendation had been implemented at the railroad for which I worked, my fatigue most likely would have been caught earlier and mistakes avoided.
(Note: As I was writing this blog, I was heartened to hear that, on March 8, the FRA announced it was seeking public input on the impacts of screening, evaluating and treating rail workers for obstructive sleep apnea.)
And while the railroads and the federal regulators are responsible for addressing this epidemic, so too must railroad workers recognize the dangers of working while fatigued. Yet many are compelled to make money and want to stay ready to react at any hour of the day to avoid missing the opportunity to get paid. To a certain extent, I understand this. And that’s why we must also work with labor unions to address this issue and provide workers the opportunity for sleep, while still allowing them the opportunity to get a paycheck and progress in their careers.
Fatigue in transportation is such a significant concern for the NTSB that it has put “Reduce Fatigue-Related Accidents” on its Most Wanted List of transportation safety improvements. It is not just an issue in rail, but an issue in all modes of transportation that must be addressed.
As a former railroad worker and now as a supervisor of railroad accident investigators, I can tell you we still have a long way to go to address this issue. Doing so will require the joint efforts of the regulator, the operator, and the employee. These efforts must be undertaken, because we can’t keep running down this dangerous track.
Georgetta Gregory is chief of NTSB’s Railroad Division.