Friday, January 9, 2015

Fatigue an Important Cause of Road Crashes



Driver Fatigue is an important cause of road crashes.

  Driver fatigue is very dangerous condition created when a person is suffering symptoms of fatigue while driving, often resulting from the hypnotic (Inducing sleep; soporific or hypnosis) effect especially during nighttime (peak levels at night can be 10 times daytime levels) driving either falling asleep at the wheel or so exhausted they made serious - and fatal - driving errors. 

However the early hours of the morning and the middle of the afternoon are the peak times for fatigue accidents. Also long journeys on monotonous roads, such as motorways, are the most likely to result in a driver falling asleep. Sunlight signals or bodies when to be awake. But even deprived of any natural light, we will still feel a surge of fatigue in the middle of the night and to a lesser extent, in the middle of the afternoon. The latest research also shows the grogginess right after you wake up can also be dangerous. 

There's a strong possibility that the driver fall asleep and run off the road. Tiredness and fatigue can often affect your driving ability long before you even notice you’re getting tired. Fatigue related crashes are often more severe than others because driver's reaction times are delayed or they have failed to make any maneuvers to avoid a crash. Symptoms of driver fatigue include heavy eyelids, frequent yawning, a drifting vehicle that wanders over road lines, varying vehicle speed for no reason, misjudging traffic situations, and seeing things "jump out" in the road, feeling fidgety or irritable and daydreaming.

A study by National Central University in Jhongli, Tatung University, Taiwan; recently reported at New Scientist magazine that "driving for just 80 minutes without a break can make motorists a danger on the roads". They found that drivers who do not take frequent rest stops have slower reactions than those who break up long journeys.

People run a higher risk of succumbing to driver fatigue between 2am and 6am and during what is known as the "2pm slump". Studies show the number of accidents increase according to the time of day and the number of hours driven. High risk occupations include night-shift workers, airline crew, students, commercial drivers, medical staff, sales representatives and journalists.

Enforcement of duty cycle limitations; suppose bus drivers operating on irregular schedules suffer greater subjective fatigue and physiological stress than drivers operating on a regular schedule. Service regulations in Canada reported that after 24 hours of duty, workers experience a25% decrease in performance.

A new in-depth on-scene study last year in the Vehicle Safety Division, at Chalmers University of Technology, in Sweden reveals that driver fatigue, slippery roads, and inexperience could be just as important and should be factored into the design of new vehicle safety features.

Stats of Road Crashes as a cause of driver fatigue:

Recent international research has suggested that driver fatigue is under- represented in accident statistics, and some estimates show that it could be a contributing factor in twenty to twenty four percent of fatal crashes.
A study conducted by the Adelaide Centre for Sleep Research shown that drivers who have been awake for 24 hours have an equivalent driving performance to a person who has a BAC (blood alcohol content) of 0.1 g/100ml, and is seven times more likely to have an accident.

Photo from the scene where a Greyhound bus from New York City struck a tractor-trailer early Wednesday on Interstate 80 in central Pennsylvania, killing a woman, critically injuring four other people and sending dozens to the hospital. Cause is still under investagation


In the USA:

In the USA a series of studies by the National Transportation Safety Board (NTSB) have pointed to the significance of sleepiness as a factor in accidents involving heavy vehicles.
The NTSB came to the concluded that 52 per cent of 107 single-vehicle accidents involving heavy trucks were fatigue-related; in nearly 18 per cent of the cases, the driver admitted to falling asleep. Summarizing the US Department of Transportation's investigations into fatigue in the 1990s, the extent of fatigue-related fatal accidents is estimated to be around 30%. Research shows that driver fatigue is a significant factor in approximately 20% of commercial road transport crashes and over 50% of long haul drivers have fallen asleep at the wheel.
Recently The National Highway Traffic Safety Administration (NHTSA) estimate that there are 56,000 sleep related road crashes annually in the USA, resulting in 40,000 injuries and 1,550 fatalities.

An analysis of road accidents between 1990 and 1992 in North Carolina found 5,104 accidents (0.5%) in which the driver was judged to have fallen asleep.  A survey of 205 drivers in another State found that 31% admitted having dozed off at least once while driving during the preceding twelve months.
One study calculated that 17% (about 1 million) of road accidents are sleep related. A 1995 study suggested that 2.6% of accidents caused by driver inattention were due to fatigue
A study of road accidents on two of America’s busiest roads indicated that 50% of fatal accidents on those roads were fatigue related. Another study claims that 30% - 40% of accidents involving heavy trucks are caused by driver sleepiness. Truck driver fatigue was a particular problem in single-vehicle fatal crashes. In 2002 alone the Total Cost of Fatigue-Related Crashes (in 1999 Dollars) exceeded $2.3 billion.

Rubbernecking, driver fatigue (12%) and looking at scenery were some of the leading causes of distraction-related traffic crashes, according to a study in 2003 over more than 2,700 crash scenes involving distracted drivers and nearly 4,500 drivers; conducted by Virginia Commonwealth University for the Virginia Department of Motor Vehicles.

In 2010 fatigue was involved in at least 18% of fatal accidents and accounts for about 7% of all accidents.
The Government’s Road Safety Strategy, “Tomorrow’s Roads: Safer for Everyone” identifies driver fatigue as one of the main areas of driver behavior that needs to be addressed if the target for reducing the number of people killed and seriously injured in road accidents by 40% by 2012 is to be achieved.

In Australia:

One study based on coronial and police reports found that fatigue played a part in only 5 per cent of fatal crashes in 1988. A more recent survey (for 1994) based on coronial and police reports found that fatigue played a part to about 18 per cent of fatal crashes. It included not only those crashes in which police identified fatigue as a cause, but also cases where the crash description suggested 'loss of concentration' had been a contributing factor. A third review found that around 30 per cent of rural crashes in Western Australia could be attributed to fatigue. Fatigue is a major cause of crashes in Victoria resulting in some 70 deaths and approximately 500 serious injuries each year. Recently research shows fatigue is a contributing factor in around 20-25 per cent of all fatal car accidents in Victoria.

In Canada:

A collaboration study by Moller of the University Health Network and the University of Toronto Sleep Research Unit found that driver fatigue is a serious road safety issue that kills 400 Canadians every year. Also, according to a 2005 study, one in five Canadians - 4 million people - admitted to nodding off or falling asleep at the wheel at least once in the previous 12 months.

In UK, Ireland, New Zealand, Germany:

In the UK alone, almost 45,000 people are killed, or seriously injured in road accidents every year, and road safety experts consider driver fatigue is a major cause. Driver fatigue is shown to be responsible for more than 20% of traffic accidents in UK.
The Road Safety Authority (RSA) of Ireland Chief Executive Noel Brett said scientific studies prove that driver fatigue is as dangerous as driving when over the drink drive limit and warned recently that one of five driver deaths in Ireland were as a result of driver fatigue, when a motorist begins to nod off behind of the wheel of a car.

A study in New Zealand of 370 heavy motor vehicle crashes in 1997, found that driver fatigue was listed as a contributing factor in 7% of accidents. In 2006 at least 40 people lost their lives while almost 1000 people were injured because they, or the driver of the car they were in, succumbed to fatigue.

According to an investigation carried out by insurance companies in Germany, fatigue is responsible for one in four fatal motorway accidents. Another study of motorway accidents in Bavaria estimated that 35% of fatal motorway crashes were due to reduce vigilance (driver inattention and fatigue).

Key Messages for prevention:

  • Avoiding driver fatigue on long trips. The biggest mistake people make is not stopping when they are tired, thinking they can make it. Drivers should give themselves plenty of time to get to their destinations and schedule in regular breaks.
  • For long trips plan in advance so you know where you are going to take a break. Don’t work a full day and then driving for hours before leaving a good night's sleep to avoid the cumulative effect of not getting enough sleep.
  • Take a break at least every 2 hours.
  • Plan to stay somewhere overnight if you are going on a long journey and avoid heavy foods.
  • Share the driving - and make sure to take rest when you are not driving.
  • Try not to drive when you would normally be asleep (early mornings and late nights.
  • Don’t drink and drive. Not only does alcohol severely impair your driving ability, but it also acts as a depressant. Just one drink can induce fatigue. Also, avoid smoking when you drive. Smoke’s nicotine and carbon monoxide hamper night vision. If there is any doubt, have your headlights properly aimed. Misaimed headlights blind other drivers and reduce your ability to see the road. Being seen is as important as seeing.
  • Caffeine (coffee, cola drinks) provides a quick, but short-lived improvement in alertness. So, to capitalize on its benefits, one should use it only when a boost is needed. Drink water, eat fruit and healthy snacks rather than fatty and sugary food.
  • If you are taking any medication, check whether it causes drowsiness.
  • Use air conditioning to keep you more alert and will help avoid frustration and stress.
  • Adjust driving seat to an upright position is to ensure the base of your wrists can make contact with the top of the steering wheel.
  • Additionally recently New Zealand’s Accident Compensation Corporation (ACC) Programme Manager of road safety advised for busting fatigue are: "A power nap of only twenty minutes (A brief power-nap) can boost energy levels as well as improve your driving skills and alertness". The National Sleep Foundation also recommends taking a nap for 15-45 minutes.

You should look out for these signs when you are driving (long and short trips):

  • you keep yawning ,day-dreaming, wandering in lane
  • your reactions unintentionally speeding up or slowing down. Anxiety, mood states, personality and temperament as factors that may possibly affect driver fatigue.
  • you feel stiff your eyes feel heavy
  • you find you are day dreaming
  • you wander over the center line or
  • on to the edge of the road
  • you don’t remember driving the last few miles or cannot remember the last few minutes or seconds.
Need more information?
The information presented here was generated in cooperation with the Roads and Traffic Authority. You can get more information from the RTA Driver Fatigue. The Federal Office of Road Safety also has a great deal of information as does the NSW Health site.

Wednesday, January 7, 2015

Building Buses with Stainless and Aluminum

Building Buses with Steel, Stainless Steel and Aluminum


For some reason, we have received several questions lately on the various metals generally used in bus construction. This was probably expected since some of these metals have been in the news recently. Prevost has introduced aluminum luggage bay doors on their X-series coaches. Caio is putting aluminum siding on its new coaches and Setra is dipping their frames into a tank to coat them against corrosion.

I can go through some of the basic items on different metals without getting too involved with metallurgy. None of this is rocket science. In fact, I would bet that many of our tenured readers are already knowledgeable in this area. While we can provide some basic information, hard and fast rules are difficult because of differences in both bus construction and usage.

Let me start out by saying that there is no “best” bus for everyone and every application. One operator may want a local shuttle bus to operate three hours a day, transport 20 people around town, and have a useful life of 200,000 miles. Another operator will ask for a bus that will carry up to 50 people in long distance scheduled service and will last for 2,000,000 miles. Somewhat obviously, the “best” bus for each of these applications is not the same bus.

Next, let me suggest that a great deal depends on quality of construction and related longevity. Stainless steel and aluminum do not necessarily improve the quality of construction. However, they can help the bus last longer and improve resale value by reducing corrosion as the bus gets older.

A third point I feel compelled to bring up is galvanic corrosion. Using different metals in the same bus can cause problems where they join. I remember hearing more on this years ago. It appears that in recent times this concern is more under control.

A good place to start is to review some of the basic differences between the European and American bus markets and typical construction.

European coaches typically are expected to run fewer miles than on this side of the Atlantic. Bear in mind that it is less than 1,000 air miles from London to Rome so you do not put a lot of miles on a coach unless you run a tour beyond typical Western Continental Europe. Moreover, since tours are a major part of European coach operations, there is more pressure for newer coaches. Hence, it is not unusual for a European coach to be built from mild or carbon steel and have a useful life of about 1,000,000 miles. Since there are no major long distance scheduled service operations in Western Continental Europe and most of the tours are short by American standards, there is no strong demand for coaches with high longevity.

However, to be fair, I should mention that any of the European-built coaches that survive on the American market tend to be at least a cut above the standard European coach. In some cases, the export model going to America may have more features than coaches built for local use.

While coaches in Western Europe have primarily evolved around tourism, the bus industry in America started out primarily as scheduled service. Greyhound started out running between Hibbing and Alice, Minnesota and virtually all of the earlier larger bus companies were heavily involved with scheduled service.
Add to this the fact that the distance from New York to San Francisco is three times the distance from London to Rome. Hence, early bus design in the United States and Canada centered around longevity and durability. For the most part, I have no problem with suggesting that our domestic coaches (now primarily built in Canada) are easily the most durable in the world. They not only have a high stainless steel content but typically have a useful life of 2,000,000 miles or more.

When does it pay to use aluminum or stainless steel in addition to or instead of mild or carbon steel? This is a fairly typical question but, again, a great deal depends on the operator’s needs and the type of operation. The more years you plan to keep the bus, the more that stainless steel or aluminum would be a positive factor. Buses that are built to operate more than 1,000,000 miles are also good candidates for these metals. In addition, stainless steel or aluminum could be more important if residual value is a high priority to you.

Carbon or mild steel is the usual metal used in most buses that do not have a high longevity. The industry tends to define it as having no more than two percent carbon and no other appreciable alloying element. It is the most popular type of steel, is less expensive than other specialized types of steel and is generally easy to work with. Its biggest negative feature from our standpoint is corrosion. Iron in the steel mixes with oxygen in the air to form ferric oxide, forms of which are more commonly known as iron oxide or rust.

In earlier decades, many of the buses built in the United States used carbon or mild steel. It worked well for some makes and models and not so well with others. For example, Eagles were notorious for rust. There were people who unkindly suggested that if you stood close to an Eagle you could actually hear it rust. After looking at going to stainless steel, Eagle converted to CorTen (or “weathering”) steel. This tended to reduce the rust problem but is not as good as stainless steel in this area.

Carbon steel is almost always used for cutaways and other body-on-chassis buses in the United States and Canada. Since body-on-chassis buses rarely run for more than 500,000 miles, the use of stainless steel would be considered a waste of money by most people. However, I have seen cutaways that use some stainless steel in areas most prone to corrosion, such as doors and stepwells.

Temsa’s coaches coming to America have high stainless steel content. However, I have been told that Temsa will build some models using mild or carbon steel on customer request. This does reduce the price of the coach but it is more prone to corrosion. Setras are built with carbon steel but since their acquisition by Daimler, the frames are very carefully rust proofed in a cathodic dip tank at the Mercedes facility in Mannheim, Germany. Holes in the tubular steel allow the treatment to go both inside and outside of the frame members. The use of an electrical charge on the frame makes this process similar to plating and provides a very thorough coating.
Aluminum has been used in bus and coach production for a long time. There are different kinds of aluminum alloys with some less likely to suffer corrosion and some actually stronger than some steel alloys. The primary advantage of aluminum is its ability to withstand corrosion. Aluminum does react with oxygen in the air to produce Aluminum Oxide. This then typically coats the aluminum and tends to prevent any further corrosion.

A second advantage of aluminum is low weight. This can be increasingly important today when weight and ecology are important considerations. However, there are at least two disadvantages when using aluminum. One is the potential for galvanic corrosion when in contact with steel. The second is that most aluminum is not as strong as steel and hence is less appropriate for use as structural members that have to bear a lot of weight.

General Motors made good use of aluminum on many of their buses and coaches. The use of aluminum for siding was typical. What the industry called “silversiding” was actually aluminum. I note that many of the Scenicruisers ran more than three million miles before leaving the Greyhound fleet, suggesting that GM knew how to make steel and aluminum work well together.

Today we are seeing a reemergence of aluminum in buses and coaches. Its light weight and reduced corrosion are factors making it popular. I note that Prevost is now offering aluminum baggage bay doors on its X series coaches. In addition, I find it interesting that CAIO is putting aluminum siding on its coaches. I suspect that we will see more aluminum on coaches in the years ahead.

Of course, the “top of the line” as far as buses and coaches go is stainless steel. Also known as inox steel (from the French inoxydable), stainless steel is usually defined as a steel alloy with a minimum of 10.5 to 11 percent chromium content by mass.
The single biggest advantage of stainless steel is its reduced corrosion. Unprotected carbon steel tends to form iron oxide or rust when exposed to air and moisture. The rust is active and helps form more iron oxide. Since the iron oxide molecules are larger than iron molecules, the rust tends to flake and fall off. Hence, over time the carbon steel is reduced in size and in strength.

Stainless steel is stain-less, not stain-proof. The chromium in stainless steel mixes with oxygen in the air and forms a coating of chromium oxide that protects the metal from further corrosion. On the negative side, stainless steel is more expensive than carbon or mild steel. In addition, some people say that some types of stainless steel can be more brittle than mild steel and hence more difficult to work with.

Credit for introducing stainless steel into American coaches in a big way goes to Harry Zoltok, the founder of MCI. Challenged with building buses for Canadian Greyhound that could survive Canadian winters and pre-War Canadian roads, Zoltok developed a combination of platform integral construction and stainless steel that undoubtedly qualifies as the most durable type of bus ever built in any quantity. This goes a long way towards explaining why MCI has had an enviable reputation for durability and continues to enjoy a substantial market share.

However, I do give credit to other manufacturers for learning that stainless steel enhances the longevity of an already high-quality coach. Today, Prevost, Van Hool and Temsa coaches sold in the United States all have a high degree of stainless steel content.
I should at least briefly mention that we are seeing more and more plastics and similar materials being used in bus and coach construction. Bob Lee and his crew at Neoplan once developed a lightweight carbon fiber bus. Today’s modern buses typically use various types of plastics or fiberglass for front and rear caps, walls and sidings and even flooring. Their main advantage is light weight and a lack of corrosion. Although in most cases, these materials are not strong enough to be used for structural members.

Finally, for those people who have asked, the most durable American buses in the past were built with platform integral construction. This includes the popular GM coaches as well as the MCI coaches through the D model. The newer models built with tubular web frame construction have not yet met the three-million mile record of the Scenicruisers. However, it can easily be suggested that in todays operations, heavy in charters and tours rather than heavy scheduled service, coaches simply do not run as many miles as they used to.

Whether or not the top mileage makes any difference, tubular web frame integral construction appears to be replacing platform integral construction. The major reason for this is that platform integral construction tends to limit design possibilities in an era when design is increasingly important in a charter and tour market. In spite of this, I suggest that stainless steel will remain important in coach construction for a long time and we most likely will see more aluminum in the years ahead.