The humble seatbelt has been a ubiquitous part of automobiles for 50 years. The safety device has saved countless lives. But, thousands of motorists still die behind the wheel every year. In fact, U.S. Transportation Secretary Norman Mineta claims the problem of highway traffic deaths has become a "national epidemic."
According to the National Highway Transportation Safety Administration (NHTSA, Washington, DC), 42,800 people died in car crashes in the United States in 2004 vs. 42,643 in 2003. Mineta says those accidents come at an enormous cost to society. He estimates that highway crashes cost $230.6 billion a year, which translates into $820 per person.
Despite numerous challenges, automotive engineers are scrambling to find new ways to cost-effectively produce the next generation of lifesavers. Indeed, the market for high-tech vehicle safety systems, such as collision avoidance systems, lane departure warning systems, smart air bags and tire-pressure monitors, is expected to explode during the second half of this decade.
At the recent SAE World Congress in Detroit, safety was a hot topic. According to an annual study of attendees conducted by DuPont Automotive (Troy, MI), safety is the second biggest challenge currently facing the automotive design and engineering community. It ranks ahead of fuel economy and alternative powertrains, but slightly behind cost reduction.
And, the auto industry's focus on safety is growing. Indeed, the number of respondents citing safety concerns rose from 13 percent in 2004 to 15 percent in 2005. At the same time, cost reduction dropped from 33 percent in 2005 to 26 percent in 2005. A majority (64 percent) of engineers responding to the survey believe that "enhanced safety systems" are the most important attribute to consumers today. Safety ranks ahead of vehicle performance (41 percent), styling (34 percent) and fuel efficient, environmentally friendly vehicles (34 percent).
"We see double-digit growth for safety systems that advance efforts in collision avoidance, that detect occupant positioning, and actively deploy interior systems to minimize injury," says Michael Sanders, global director of automotive safety at DuPont. "Recent crash safety rankings are driving consumer demand for side air bag and air curtain systems, more robust anti-intrusion protection and laminated side glass, particularly in small cars where efficient packaging and weight reduction are essential."
A recent consumer survey conducted by J.D. Power and Associates (Westlake Village, CA) confirms that trend. Among 20 emerging automotive features, such as surround sound and driver recognition systems, "the four most desired features enhance the safety and security of vehicle occupants and are of interest to at least three-fourths of consumers surveyed," says Melissa Sauter, director of automotive emerging technologies. Side-impact air bag protection tops the list, with nearly 90 percent of respondents expressing an interest in having this feature on their next vehicle.
Publication of crash ratings by organizations such as NHTSA and the Insurance Institute for Highway Safety (Arlington, VA), and consequent greater awareness among consumers, is increasing demand for safety systems. "Competitive pressures and vehicle manufacturers' desire to differentiate their vehicles are also increasingly important factors in the safety systems market, and will remain so going forward," notes Anis Sayyad, a senior research analyst at Frost & Sullivan Inc. (San Antonio).
"Automakers are catering to this increased awareness by making more systems standard equipment," adds Sayyad. "The middle to high-end segments offer automakers more room to differentiate their vehicles based on safety systems." Sayyad predicts that the North American market for safety systems will grow from $2.8 billion in 2003 to $4.1 billion in 2010.
Automakers and suppliers are currently developing a wide variety of advanced safety systems suitable for mass production. New sensor technology, higher sensing speeds, wireless communication, onboard computing power, high-speed cameras and other technology are becoming less expensive every day, allowing engineers to create cost-effective applications.
As a result, "a new war among automakers is on the verge of breaking out," predicts Robert LaGuerra, senior automotive industry analyst at ABI Research (Oyster Bay, NY). "The main focus of this battle will be centered on safety as the key differentiator for vehicle lines. There are a host of cutting-edge safety systems in varying stages of development that will alter the consumer's perception of what makes for a ‘safe' vehicle."
LaGuerra says automakers are tackling the issue of safety from different perspectives. But, most companies are focusing on "active safety" technology. Active safety systems help drivers avoid accidents. A vehicle's tires, brakes, handling, acceleration, steering and visibility all contribute to active crash avoidance. In sharp contrast, passive safety systems, such as seatbelts, help drivers and passengers stay alive and reduce the risk of injury in a crash. Many experts believe that active safety technology will reduce fatalities by 50 percent, because they help motorists avoid accidents and collisions.
"Passive safety systems are reaching diminishing returns in terms of incremental lives saved, increasing the focus on active safety as an additional tool for mitigating injuries and saving lives," says Frost & Sullivan's Sayyad. "But, there is no move away from passive safety toward active safety. Active safety systems are mostly installed over and above passive safety features, such as standard fitment air bags and seatbelts."
"The once rigid distinction between active and passive vehicle safety has become more blurred," adds Jurgen Dickmann, head of situation evaluation, sensor functionality and sensor technology assessment at the laboratory for active safety and assistance systems at the DaimlerChrysler Research Center (Ulm, Germany).
According to Dickmann, accidents should be prevented, whenever possible, through the use of active safety systems designed to assist drivers. And when accidents are unavoidable, they should be identified as early as possible so that their impact can be diminished.
"The time leading up to an accident generally offers scope for action, since it lasts much longer than the collision itself," Dickmann points out. "In the same way that a ski binding is set to release the boot at a certain load, the safety systems in future vehicles will be able to adapt themselves more closely to individual occupants.
"The ability to evaluate situations quickly and accurately is the key to realizing accident-free driving," claims Dickmann. "Enhanced sensor technology is set to play a crucial role in this regard."
Sensors that monitor a vehicle's operating condition for anomalies that require intervention are the most commonly used safety devices. These devices trigger the safety component to respond as intended to counteract the irregularity. Vehicles typically have dozens of safety-related sensors that monitor everything from crash impacts to rollovers, tire pressure, lane-change warnings, ice presence and wheel lock up.
"It all starts with the sensor," says Larry Stockline, president of Promess Inc. (Brighton, MI). "Other elements are not relevant without sensors. Sensors must be designed for hot-cold conditions, humidity, acids such as salt, age and [insurance, litigation and warranties]. It's an Atlas of responsibility. Communication software, wire, wireless, switches and computers are all part of the solution."
"All safety-related components have to be highly reliable in their function," adds Mitch Coleman, an automotive application specialist at ATS Automation Tooling Systems Inc. (Cambridge, ON). "These devices typically have back checks that occur every time the vehicle is started to ensure their operational functionality."
According to Coleman, there are three main challenges to mass-producing sensors for automotive safety applications:
- To assemble each component to the highest level of quality to ensure that they perform as designed during an emergency event.
- To design traceability into the assembly system for tracking purposes in case a recall related to the component should occur.
- To test the component in a nondestructive manner to ensure compliance to the original design specification.
- "It is the assumption and expectation of the consumer that safety-related devices must work on demand, no matter how many years the vehicle has been in operation," notes Coleman.
As active safety applications grow, the average number of sensors per car will continue to increase. Auto Research Analysts (London) predicts that the automotive sensor market will increase 39 percent annually between now and 2010.
"Volumes will increase in the next 3 to 5 years as people see favorable statistics on the new active safety products, such as injury prevention and handling improvements," says Coleman. "The desire for such features could lead OEMs to make active safety systems standard equipment; that will significantly increase their volumes."
Traditionally, advanced technologies take time to trickle down through the many layers and segments of the auto industry. Due to pricing pressure, automakers typically unveil high-tech safety systems on high-end vehicles, which are produced in low volumes. Once a feature becomes standard, it typically becomes less expensive to make and install in all vehicle segments. But, that philosophy is starting to change.
In 2004, Honda Motor Co. (Tokyo) and Toyota Motor Corp. (Aichi, Japan) were the first nonluxury automakers to install electronic stability control and antilock brake systems across their entire North American light truck model range. At the same time, Nissan Motor Co. (Tokyo) was the first OEM to introduce a lane departure warning system on a North American passenger car.
By the end of 2006, all Honda and Acura vehicles will have standard front, side and side-curtain air bags. In addition, the automaker will include stability control with anti-rollover sensors in all of its trucks, sport-utility vehicles (SUVs) and minivans.
Japanese and European automakers typically provide active safety systems as standard equipment, whereas U.S. automakers offer them as enhancements or options at additional costs. "This is a way for domestic OEMs to keep their vehicle base prices lower to be more competitive with the foreign OEMs," Coleman points out.
"Differences in the consumer markets and infrastructure between North America and Western Europe lead to differential rates of safety system installations," adds Frost & Sullivan's Sayyad. "A time lag is seen between the North American market vis-a-vis the European and Japanese markets."
Many factors contribute to those differences, such as consumer preferences, driving habits, demographics, regulatory frameworks and infrastructures. However, Detroit is ahead of the curve when it comes to adopting some new safety technology, such as tire pressure monitoring systems.
"Vehicle manufacturers attempt to control the cost of [developing and installing] safety systems within a certain budgeted percentage of the total vehicle price," Sayyad points out. "For suppliers, the key challenge is to offer highly sophisticated and reliable active safety systems at a reasonable price. Other challenges facing automakers and suppliers are system reliability, technical challenges in systems networking, reluctance of vehicle manufacturers to add content, and rising consumer expectations for safety as standard equipment included in the base price."
Despite those pressures, Sayyad says active safety systems are not necessarily more expensive to manufacture than passive safety systems. For instance, anti-lock brakes (ABS) have been around a number of years and are relatively inexpensive because the technology has been widely adopted. "More critical than manufacturing challenges, such as ease of mass-manufacture, is the challenge to increase system adoption rates on vehicles, which brings increased volumes," notes Sayyad.
However, the active safety market is very diverse, with numerous product segments. Each pose unique challenges and opportunities for automotive engineers.
Electronic stability control is a proven active safety technology that can help a driver maintain safe braking and steering. It significantly reduces the danger of skidding and rollover accidents. Microelectronics detect when loss of vehicle control is imminent and automatically apply brake pressure to specific wheels, allowing the driver to maintain steering control and continue in the intended direction.
A recent study conducted by NHTSA on vehicles equipped with stability control found a 35 percent decrease in single-vehicle crash risks for cars and a 67 percent decrease for SUVs. Fatalities in single-vehicle crashes were reduced by 30 percent in cars and 63 percent in SUVs.
According to CSM Worldwide (Farmington Hills, MI), 18 percent of vehicles produced today in North America are equipped with electronic stability control. But, this figure is expected to reach 28 percent by 2010, an increase of 1.9 million units. That pales in comparison to Europe, however, where 53 percent of vehicles produced in 2005 will be equipped with the technology.
"This difference is a direct result of government regulation making ABS standard for all vehicles beginning in 2005," says Bill Rinna, manager of North American component forecasts at CSM Worldwide. "Knowing ABS will be standard, OEMs looked for ways to differentiate vehicles from the competition. The answer was vehicle stability control (VSC), which led to cost competition between stability control system suppliers.
"The lower cost benefited the consumer and enabled European manufacturers to tweak a less expensive chassis setup to enhance suspension, chassis and steering inefficiencies," adds Rinna. "In North America, where ABS is not regulated by the government, the VSC trend began in 2004 when OEMs began asking for a reduction in VSC system prices across the board from suppliers. This reduction in cost, which eventually worked out to about $100 per system, is driving competition in much the same way it has in Europe."
DaimlerChrysler, Ford Motor Co. (Dearborn, MI) and General Motors Corp. (Detroit) recently announced that they will be offering VSC as a standard feature on all SUVs sold in North America. According to Rinna, that's a "not too subtle message that the companies are getting serious about safety in vehicles. The more visibility given to the benefits of technologies such as VSC, the more consumers will request them."
Air Bag Advances
Driver- and passenger-side front air bags have been mandatory equipment on all U.S. passenger cars since 1998. Side-curtain and rear passenger air bags are currently used on most luxury cars and some high-end SUVs. And, NHTSA's proposed upgrade to Federal Motor Vehicle Safety Standard 214 would require side-impact protection, such as curtain air bags, to be phased in over the 2006-2009 period.
"There has been increased demand for equipment to assemble automotive safety products, particularly in the air bag product line," notes ATS Automation Tooling Systems' Coleman. "The proliferation of air bags in the passenger compartment is considerable, with some vehicles featuring as many as 12 different devices. Future luxury cars could have as many as 17 air bags to protect occupants in both the front and back seats."
As more air bags are installed in vehicles, engineers have been forced to miniaturize the systems. "Today, much smaller air bags are used vs. 10 years ago," says Gary Grebe, marketing director at Cincinnati Test Systems Inc. (Village of Cleves, OH). For instance, the propellant modules that force air into the bag are shrinking in size. The sealed cylindrical devices used to measure approximately 3 inches in diameter, but today they are approximately 1 inch, especially for side-impact applications.
While the basic technology behind air bags is fairly mature, engineers continue to push the envelope. For instance, Siemens VDO Automotive AG (Regensburg, Germany) has developed sensors that activate air bags according to passenger weight. The system is currently used in the Mercedes-Benz S-Class sedan.
It uses four sensors embedded in the seat to measure weight load at each point to the nearest 150 grams. A metal spring in the sensor compresses by a maximum of 0.2 millimeter, depending on the pressure acting on the seat. This compression is registered and passed on to the air bag control unit as an electrical signal.
Software analyzes the measured weight and can classify occupants into five categories, from small child to heavy adult. If an accident occurs, the timing and force of the air bag's actuation are automatically matched to the individual occupant, based on this classification, to offer increased protection and reduced risk of injury when it is deployed.
Siemens engineers have also developed a crash impact sound sensor that monitors the vibrations in a vehicle's chassis. It "hears" a crash before it occurs and assesses the seriousness of the accident in just a few milliseconds. The air bag control unit then triggers the seatbelt tensioner and the necessary air bags to protect the vehicle occupants.
A team of researchers at the Cranfield Impact Centre Ltd. (Cranfield, England) have developed an ultrasound finger scanner and processor that fine-tunes air bags and seatbelts. Finger readings are used to estimate the skeletal strength of an individual's body--particularly the chest, which can be severely injured when air bags deploy. By scanning the bone strength of vehicle occupants, the system is able to assess their injury tolerance limits and determine the maximum protection required.
More than 30 percent of accidents in Europe and the United States are caused by lane changes or unintentional lane departure. However, new technology to reduce this risk is being developed for passenger vehicles, based on earlier efforts in the commercial trucking industry.
Engineers at Valeo (Paris) have developed a product called LaneVue. Using infrared beams linked to an electronic control unit, the lane departure warning system monitors the lane markings ahead of the car. If the car strays over the line without the indicator being activated, the driver is alerted by the vibration of his seat on the side of the line being crossed.
The system, which was developed with Iteris Inc. (Anaheim, CA), consists of a miniature video camera that uses proprietary software algorithms to continuously monitor lane markings in front of the vehicle. During unintentional lane departures--detected when a driver fails to use the turn signal--the driver is alerted to take corrective action by an audible tone, a rumble in the driver's seat or a shake in the steering wheel. Engagement of the turn signal shuts off the system, which also features a cancel switch.
LaneVue is currently available on Citroen C4 and C5 sedans in Europe. Nissan's Infiniti division was the first car manufacturer to install the system on a production vehicle for the U.S. market. The lane departure warning system is currently available as an option on the 2005 Infiniti FX SUV and the 2006 M35 and M45 sedans.
Other suppliers have been developing lane departure systems that use radar sensors rather than cameras. For instance, the Lane Change Assistant from Hella KgaA Hueck & Co. (Lippstadt, Germany) uses 24 -gigahertz radar sensors to monitor vehicles approaching from behind.
Drivers are warned of critical situations by acoustic, haptic or optical signals. Two radar sensors, located on both sides of a vehicle, recognize other road users or objects behind and alongside it. The sensors have a range of 50 meters and are not affected by weather conditions.
If there is a vehicle in the adjacent lane and the driver intends to change lanes, he is warned either by an optical signal, such as a red light in the mirror, an acoustic signal, such as a warning sound in the radio loudspeaker, or a haptic signal, such as "shaking" of the steering wheel.
The product will be available next year, in addition to a companion item that controls proximity to vehicles in front. Using infrared laser technology, the adaptive cruise control system recognizes hazards in road traffic at an early stage. Unlike camera-based systems, it is extremely effective in limited visibility conditions, such as fog or snow.
The system scans vehicles in the same lane traveling in the same direction. It determines the distance between the vehicles and their relative speeds. By adjusting engine performance and braking force accordingly, it ensures that the distance to the vehicle in front remains constant in relation to the vehicle's own current speed.
Hella claims that the performance, functional ability and reliability of infrared laser technology is comparable with much more expensive radar technology. The infrared proximity sensor used for its system is based on optoelectronic measuring technology: The time it takes light to travel a certain distance is determined following the principle of light detection and ranging (LIDAR). A brief light impulse is transmitted and the return scatter signal is recorded with the aid of electronics.
Engineers at Robert Bosch GmbH (Gerlingen-Schillerhohe, Germany) have developed an adaptive cruise control system that uses advanced radar technology. It detects vehicles cruising in front, calculates their traveling speeds and maintains a safe distance between vehicles through active brake and engine control. As soon as there is no vehicle within the scanning range, the system accelerates the car to the preselected speed.
Four overlapping radar lobes scan the area up to 200 meters in front of the vehicle. By emitting specifically modulated frequencies combined with corresponding evaluation algorithms, the system is able to calculate the speed of the vehicles scanned and the distance to them. The new BMW 3 Series is one of the first cars to feature the technology.
Approximately 85 percent of all burst tires are a result of gradual pressure loss that was not recognized on time. Earlier this year, NHTSA issued a mandate that requires all passenger cars sold in the United States to have tire-pressure monitoring systems beginning with the 2006 model year. The regulations require tiremakers to install a system that can detect when one or more of a vehicle's tires are 25 percent or more below the recommended inflation pressure.
Phase-in of the new regulation will begin Sept. 1, 2005. All new four-wheeled vehicles weighing 10,000 pounds or less must be equipped with the monitoring system by the 2008 model year.
According to NHTSA, underinflated tires can adversely affect fuel economy, lead to skidding, and loss of control and hydroplaning on wet surfaces. They can also increase stopping distance and the likelihood of tire failures.
Automotive safety experts estimate that 120 lives a year will be saved when new vehicles are equipped with tire-pressure monitoring systems. In addition, consumers should see improved fuel economy and increased tire life. The OEMs' average cost per vehicle is estimated to be between $48.44 and $69.89, depending on the technology used: direct measurement or indirect measurement.
Direct measurement systems monitor the actual pressure and temperature value of the air in tires, which is then sent to a module for evaluation. Sensors are located on the inside of the wheels.
Indirect measurement systems utilize ABS speed sensors to assess differential speeds of the wheels and calculate changes in tire pressure on the basis of algorithms. If the relative differential speed of one wheel suddenly exceeds a calculated threshold compared to the other wheels, the system assumes that the air pressure in the wheel in question has fallen and an alarm is activated.
Beru AG (Ludwigsburg, Germany) offers a system that features lithium battery-powered electronics that measures tire pressure and temperature in short intervals. These values are transmitted by a high-frequency antenna to a central electronic control device where they are evaluated. The direct measurement system alerts the driver if there is a 0.2 bar deviation to prevent insufficient pressure, loss of pressure or a flat tire.
Engineers at SmarTire Systems Inc. (Richmond, BC) have developed a battery-less system that monitors all tires independently, ensuring they are correctly inflated and running optimally. "A passive sensor inside each tire is energized by an antenna located within each wheel arch," says company president Robert Rudman. If an air pressure or temperature problem occurs, drivers are immediately alerted so that they can take the appropriate corrective action. Rudman claims that eliminating the battery in the sensor "greatly reduces its weight, size and cost."
After various active safety technologies have been perfected, an even bigger challenge for automotive engineers will be to get all the systems interacting. Indeed, the increasing electronic content and complexity of safety systems is leading to efforts to integrate the various systems. The goal is to cross-link many standalone control units. Software will allow various components to communicate with each other.
Active-passive integration involves using the sensors, electronics and software developed for active safety systems, such as stability control and collision avoidance systems, to be used for readying passive safety systems into a stage of alert.
"Engineers have pretty much exhausted the possibility of obtaining any large improvement in vehicle safety through passive systems," says ABI Research's LaGuerra. "During the next 10 years, there will be more focus on getting existing sensor technologies to work with each other and cross-share information, which is a requirement for active safety systems. There will also be more by-wire technology used for braking and steering applications."
"The development of systems to provide early warning of potential accident situations will remain one of the biggest challenges for road safety in the years to come," adds DaimlerChrysler's Dickmann. "The major challenge [is] to link up the systems we already have in order to form one overall system."
However, before that happens, "several major hurdles must be overcome," warns LaGuerra. For instance, je says one big question that has to be addressed is the issue of when drivers have "control" of a vehicle and how much control they have. "As you go from passive to active safety systems, the way you inform the driver of an impending accident is important," he points out. "Too much information can end up being a distraction.
"Software development and standardized parts are also important," says LaGuerra. Lack of standardization of both hardware and software has made systems integration more difficult, contributing to rising electronic warranty issues, and has resulted in escalated manufacturing costs. That has made it difficult for automakers to add more systems, such as active safety, across a wide range of vehicle segments.
Some competitors are starting to come together to address this issue. For instance, a group of leading air bag suppliers recently formed the Safe-by-Wire Plus consortium. Participants include Autoliv Inc. (Stockholm, Sweden), Robert Bosch, Continental Temic microelectronic GmbH (Nuremberg, Germany), Delphi Corp. (Troy, MI), Key Safety Systems Inc. (Sterling Heights, MI), and TRW Automotive Holdings Corp. (Livonia, MI). The group plans to combine their knowledge to define a global standard for networking safety systems for the benefit of automotive manufacturers.
The goal of the consortium is to combine two independent, competing automotive safety bus standards into a single global standard that captures the best features from each. Through component standardization, the consortium expects to help reduce development costs and extend the benefits of economies of scale to automotive manufacturers, thus allowing more efficient integration of advanced safety features. The royalty-free standard should lead to rapid acceptance by OEMs and suppliers.
Autoliv, Bosch and Continental Temic have also cooperated in the development of the PSI5 peripheral sensor interface, an open standard for universal automotive applications. It meets the needs of vehicle manufacturers for interface standardization. The global, open standard will be used in future generations of sensors in occupant safety systems.
"The introduction and refinement of these systems are stepping stones toward a larger plan to integrate all the ancillary systems into one fully interactive and sophisticated safety system," concludes ABI Research's LaGuerra. "The ultimate goal is to have braking, steering, suspension and other systems interacting and working together to provide a safer driving experience."
Making Sense of Safety
A car that may represent the shape of things to come in safety generated a lot of attention at the recent Geneva Motor Show. Rinspeed Inc. (Zumikon, Switzerland) displayed a concept vehicle that takes automotive safety to a personal level. It features numerous sensors and electronic controls that gather and analyze biometric data about the driver.
The three-seat Senso "senses" the driver by measuring his or her biometric data. It then keeps the individual alert by applying elements of smell, sound, touch and vision.
A biometric watch located in the cockpit (insert) measures the driver's pulse. A camera records driving behavior, such as how well the motorist changes lanes and at what speed he approaches traffic in front. Depending on what condition the individual appears to be in, four small LCD monitors emit stimulating, relaxing or neutral color patterns (orange, blue and green, respectively) into the driver's line of vision. The optical stimuli are reinforced by unique sounds stored digitally on a computer.
In case that's not enough, special scents flow into the car through ventilators. Vanilla-mandarin has a calming effect on the driver, while citrus-grapefruit is more stimulating. If the central computer system detects any symptoms of fatigue, electric motors integrated into the seat shake the driver awake by vibrating.
"The risk of an accident is significantly reduced if the person behind the wheel is relaxed and wide awake," claims Frank Rinderknecht, president of Rinspeed. His futuristic vehicle uses a 3.2 liter engine from a Porsche Boxster sports car that is modified to run on gasoline and natural gas.