Toxicological Information
The accident drivers toxicological specimens were split and examined by two laboratories: (1) the Maryland Office of the Chief Medical Examiner found the specimen negative for drugs and ethanol and reported that its carbon dioxide levels were normal, and (2) the Federal Aviation Administrations Civil Aeromedical Institute Toxicological Laboratory found the specimen negative for drugs and ethanol.

Survival Aspects

The accident driver was ejected during the accident sequence and sustained fatal injuries. The Explorer was equipped with three-point lap/shoulder belt restraints in the four outboard seat positions and a two-point lap belt in the rear center seat position. The drivers restraint system was equipped with a belt pretensioner in the retractor, which activated when the supplemental air bag restraints deployed. The drivers seat belt and the webbing showed no evidence of use3 at the time of the accident. The driver and front right
Evidence of use is usually crash-induced loading marks, such as stretch marks and abrasions.
seat positions were equipped with frontal supplemental air bags that deployed as a result of the accident. The four occupants of the Windstar sustained fatal injuries. The front seat passenger was ejected during the accident sequence. The vehicle was equipped with threepoint lap/shoulder belt restraints in the front and rear seats. The drivers and both rear seat restraint systems exhibited signs of use. The front seat passengers restraint system did not show signs of use. An examination of the front seat tracks revealed significant damage; however, the tracks remained attached to their anchorage points. The Windstar was equipped with front dual-threshold air bags, which deployed. The Jeep driver sustained minor injuries; the two rear seat occupants were uninjured. The Jeep was equipped with three-point lap/shoulder belt restraint systems in the outboard positions and a lap belt in the center rear seat, which were functional. The drivers three-point lap/shoulder belt showed signs of use. The right rear seat occupant (the 3-year-old) was secured in a child safety seat that met U.S. Department of Transportation (DOT) standards, and the center rear seat occupant (the 11-week-old) was secured in an infant safety seat that met DOT standards. The child safety seat had been removed before the National Transportation Safety Boards inspection. The base of the detachable infant safety seat was attached and connected to the center lap belt.
Accident Driver Information
At the time of the accident, the 20-year-old driver held a valid Virginia drivers license issued February 2, 1999. (Her driving license instruction permit was issued July 1, 1997.) A review of her Virginia driving record revealed no history of previous traffic violations or accidents. The driver successfully completed a high school drivers education class, which included classroom and on-the-road instruction, while in the 10th grade during the 1997-98 school year. According to the drivers mother, with whom she resided, the drivers actual driving experience consisted of the infrequent use of vehicles that she borrowed from friends during the 3 years before the accident. She had not previously owned a motor vehicle, and her mother did not own one at the time of the accident. She had not driven the accident vehicle before picking it up from the automobile dealer 2 hours before the accident. The drivers mother said that her daughter was in good general health and was not using any type of medication. A review of the drivers medical records found no history of chronic or acute ailments or illnesses. The Safety Board compiled a 72-hour work-rest history for the accident driver from interviews with her mother and male friend. On Tuesday, January 29, 2002, she worked for 7 hours and slept 7 hours Tuesday night. She had Wednesday off from work and slept 7 hours Wednesday night. On Thursday, she worked 8 hours and slept 7 hours Thursday night. On Friday, the day of the accident, she worked 7 hours.

Meteorology

Wind Advisories Traffic on bridges is more exposed to the effects of wind. On the day of the accident, the Maryland Transportation Authority (MTA)10 placed a wind-warning advisory in effect at all MTA bridges from 9:45 a.m., February 1, 2002, until 7:16 a.m., February 2, 2002, due to high winds in the region. Wind advisories were broadcast over the local media.
9 Maryland Department of Transportation, Report to the Maryland General Assembly Senate and Taxation Committee and House Appropriations Committee, Study of Guardrail End Treatment and Height Deficiencies, November 1, 2002.
Established in 1971, the MTA is responsible for constructing, managing, and operating Marylands toll facilities. The MTA oversees seven toll facilities: a turnpike (a 50-mile section of I-95), two tunnels (Fort McHenry Tunnel and Baltimore Harbor Tunnel), and four bridges (Thomas J. Hatem Memorial Bridge; Francis Scott Key Bridge; William Preston Lane, Jr. Memorial Bridge; and Governor Harry W. Nice Memorial Bridge).
Surface Weather Observations The National Weather Service (NWS) issued a Surface Analysis Chart for 7:00 p.m. on February 1, 2002, showing that the accident site was on the western, or cold-air, side of a complex-occluded frontal system.11 The closest surface weather observation stations to the accident site were at Andrews Air Force Base (Andrews AFB), about 5.5 miles south; Ronald Reagan Washington National Airport (DCA), about 10 miles to the southwest; and BaltimoreWashington International Airport (BWI), about 22 miles to the northeast. (See figure 14.)
Figure 14. Area map showing location of surface weather observation facilities relative to the accident location. Andrews Air Force Base. Andrews AFB reported the following weather conditions at 7:55 p.m.: wind from 310 sustained at 23 mph, gusting to 39 mph; visibility 7 miles; few clouds at 3,000 feet, scattered clouds at 10,000 and 20,000 feet; temperature of 46 F; dew point 27 F; and altimeter 29.98 inches of mercury. Remarks: peak wind recorded from 300 at 41 mph at 7:17 p.m.; peak wind from 300 at 44 mph reported at 7:56 p.m.; wind from 310 sustained at 24 mph, gusting to 32 mph, reported at 8:55 p.m.; and visibility and sky conditions unchanged.
A front formed by a cold front overtaking a warm front and lifting the warm air above the earths surface.

Pavement Coefficient of Friction On February 5, 2002, the SHA Structures and Pavement Inspection Division performed dry pavement friction tests at the accident site. Using a trailer-mounted testing device, personnel conducted five dry pavement friction tests in each direction. On May 15, 2002, the SHA carried out both wet and dry pavement tests using a treaded tire that conformed to American Society for Testing and Materials standard E274-97.13 Before the accident, as part of its annual pavement performance-monitoring program, the SHA had
A transfer of phosphorus from the needle to the dial at impact.
Standard test method for skid resistance of paved surfaces using a full-scale tire. This test method uses a measurement representing the steady-state friction force on a locked test wheel as the wheel is dragged over a wet paved surface under constant load and at constant speed while its major plane is parallel to its direction of motion and perpendicular to the pavement.
conducted friction tests at three locations within a mile of the accident site. Table 7 shows the results of these tests.
Table 7. Pavement friction tests.
Date February 5, 2002 Direction Northbound Southbound May 15, 2002 Northbound Northbound 2000 Northbound Southbound Friction number* 61.0 (dry) 57.0 (dry) 72.0 (dry) 43.0 (wet) 46, 47, 50 (wet) 45, 45, 47 (wet)
*A friction number represents the frictional properties of the pavement. These numbers are used to evaluate the pavements skid resistance relative to other pavements and/or to evaluate the change in the pavements skid resistance over time. The higher the number, the more skid resistance the pavement provides.
Simulation The Safety Board evaluated the Explorers controllability in crosswinds and the potential effects of a driver-delayed reaction time due to wireless telephone use. Investigators used Simulation Model Non-linear (SIMON) software14 to calculate the vehicles movement, Human Vehicle Environment (HVE) software15 to visualize the vehicles movement, and AutoCAD Land Development Desktop software16 to build the accident scene based on three-dimensional mapping data obtained at the accident site. Safety Board staff modeled the two-door accident vehicle using the 1991-1994 four-door Explorer in the HVE vehicle library and modifying its wheelbase, fore and aft center of gravity, vehicle weight, and sprung mass moments of inertia to match data provided by Ford Motor Company for a 1998 two-door Explorer. The two wind speeds used in the simulations were the 23-mph-sustained wind measured at Andrews AFB and the 44-mph wind gust. Investigators used various wind gust durations in the simulation, since the exact duration of the gusts at the time of the accident was unknown. Ford Motor Company also provided wind tunnel-derived aerodynamic coefficient data. The two ranges of driver reaction times used in the simulation were (1) for an alert driver reaction (0.30 to 0.59 second) based on the median reaction times of young drivers to abrupt wind gusts17 and (2) for a wireless telephone user driver reaction (0.685 to 1.15

Table 8. Accident drivers wireless telephone record for February 1, 2002.
Number 15 Time 4:00 p.m. 4:03 p.m. 4:43 p.m. 6:16 p.m. 6:22 p.m. 6:23 p.m. 6:33 p.m. 6:34 p.m. 6:57 p.m. 6:59 p.m. 7:07 p.m. 7:23 p.m. 7:24 p.m. 7:55 p.m. *8:00 p.m. Incoming or Outgoing Outgoing to a number in Arlington Outgoing to voice mailbox Outgoing to a number in Occoquan, Virginia Incoming from the male friends number Incoming from the male friends number Outgoing to the male friends number Outgoing to the male friends number Outgoing to the male friends number Incoming from the male friends number Outgoing to the male friends number Incoming from the male friends number Outgoing to the male friends number Outgoing to the male friends number Incoming from the male friends number Outgoing to the male friends number Length in Minutes 3
*The accident occurred about 8:00 p.m.
Nationwide and Worldwide. According to the Cellular Telecommunications &
Internet Association, the number of wireless telephone subscribers in the United States in April 2003 was 144,770,650.19 This figure represented about 76 percent of the 191 million licensed U.S. drivers.20 (Not all wireless telephone subscribers were drivers license holders.) Also, according to the association, nearly 118,000 wireless telephone calls are made to 9-1-1 and other emergency numbers each day, totaling more than 43 million calls annually. In its 1997 study, An Investigation of the Safety Implications of Wireless Communications in Vehicles, NHTSA estimated that at any given time during daylight hours, 3 percent of U.S. drivers were talking on a handheld wireless telephone. Observational studies21 in Dallas, Texas, (during an afternoon rush hour) found a 5-percent use rate and in Washington State a 3.5-percent use rate. In a 2002 North Carolina study,22
Information accessed on May 19, 2003, from <http:www.wow-com.com>.
U.S Department of Transportation, National Highway Traffic Safety Administration, Traffic Safety Facts 2001 (Washington, DC: NHTSA, 2002).
21 Anne T. McCartt, Elisa R. Braver, and Lori L. Geary, Drivers Use of Handheld Cell Phones Before and After New York States Cell Phone Law, Insurance Institute for Highway Safety (Arlington, VA: June 2002).
Jane C. Stutts, Herman F. Huang, and William W. Hunter, Cell Phone Use While Driving in North Carolina: 2002 Update Report, University of North Carolina, Highway Safety Research Center, December 2002.
the authors estimated that 58.8 percent of the States licensed drivers had used a wireless telephone while driving. A recent survey23 performed by The Gallup Organization for NHTSA indicated that 25 percent of the 4,010 drivers interviewed had used a wireless telephone while driving. According to a U.S. General Accounting Office report24 on wireless telephone health issues, the number of wireless subscribers increased from 16 million in 1994 to 110 million in 2001. The report also states that some experts project that worldwide wireless telephone use will reach 1.2 billion subscribers in 2005. In Austria, Finland, Italy, Norway, South Korea, and Sweden, more than half of the populations subscribe now. Wireless Telephone Use and Driving In its 1997 report, NHTSA characterizes wireless telephone use while driving a form of driver distraction. According to NHTSA research, driver distraction occurs when a driver is delayed in the recognition of information needed to safely accomplish the driving task because some event, activity, object, or person within or outside the vehicle compels or induces the drivers shifting attention away from the driving task.25 Other researchers have defined driver distraction as any activity that takes a drivers attention away from the task of driving26 and have identified four categories of distraction: visual, auditory, biomechanical, and cognitive. For example, talking on a handheld wireless telephone might involve auditory, biomechanical, and cognitive distraction. During the 1990s, the use of wireless telephones and other wireless communication devices while driving became the subject of debate as government agencies considered restrictive legislation. Research established that when auditory and visual tasks are performed simultaneously, performance on both tasks is degraded through slowed responses, reduced accuracy, or both.27 Research performed in driving simulators28 and in actual driving environments29 suggested that the cognitive demands of wireless telephone conversations may lead to driver distraction. A Canadian study concluded that wireless telephone units that allow hands-free operation offer little, if any, safety

Young Drivers. In 2001, 6.8 percent of the driving population was age 20 years or
younger (13 million drivers of 191 million total drivers).54 Of all drivers involved in fatal accidents, 14.3 percent were age 20 years or younger (8,253 of 57,480 total drivers).55 According to NHTSA, when driver fatality rates are calculated on the basis of estimated annual travel, teen drivers (16 to 19 years old) have a fatality rate about four times higher than the fatality rate for drivers 25 to 69 years old. In addition, NHTSA estimated that all highway crashes cost society about $231 billion a year, which includes $42 billion for crashes involving drivers between 15 and 20 years old.
Distraction, Particularly, Wireless Telephone Use. The reported incidence of
wireless telephone use in accidents is low. According to Congressional testimony,56 NHTSA Fatality Analysis Reporting System (FARS)57 data for the year 2000 indicated that 37,409 fatal crashes occurred; in 101 of those crashes a wireless telephone was present. At the time of the testimony, only Minnesota and Oklahoma included on their accident reports a data field for wireless telephone use as a contributing factor.
54 U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2001 (Washington, DC: FHWA, 2002). 55 56
NHTSA, Traffic Safety Facts.
NHTSA testimony before the House Committee on Transportation and Infrastructure, Subcommittee on Highways and Transit, on May 9, 2001. FARS, maintained by NHTSA, is a census of all crashes involving a motor vehicle traveling on a traffic way customarily open to the public that results in the death of a person (occupant or nonmotorist) within 30 days of the crash.
According to the NHTSA testimony, before a data field for wireless telephone use was added to accident reports, the data were obtained from accident report narratives, provided the investigating officer had added that information to the report. Now, driver distractions are included in the Model Minimum Uniform Crash Criteria Guideline 2003.58 The codes for these data elements are for a driver who is: Not distracted. Distracted by an: Electronic communication device (wireless telephone or pager), Other electronic communication device (navigation device or palm pilot), Other distraction inside the vehicle (radio or another passenger), and Object outside the vehicle (road sign or another vehicle).
According to the Governors Highway Safety Association, as of November 2002, 16 States59 code wireless telephone use as a data element on their accident investigation forms. The AAA Foundation for Traffic Safety funded a study by the University of North Carolina Highway Safety Research Center60 to examine the role of driver distraction in traffic crashes. This study, issued in 2001, used 1995 through 1999 narrative data from the NHTSA crashworthiness data system and 2 years of North Carolina police-reported crash narratives. Researchers found that driver distraction was involved in 8.3 percent of accidents and that the reported cases of using or dialing a wireless telephone were 1.5 percent of the distractions among distracted drivers. In addition, the researchers reported that young drivers (under 20 years of age) were the most likely to be involved in distraction-related crashes. In a 2002 North Carolina study,61 researchers did a computerized narrative search of all reported crashes that occurred in the State from January 1, 1996, through August 31, 2000. They identified 452 wireless telephone-related crashes and nearly 1.1 million that did not involve wireless telephones.

58 The Model Minimum Uniform Crash Criteria (MMUCC) represent a model minimum crash data set and have specific attributes for each data element. The Governors Highway Safety Association, NHTSA, the FHWA, and the Federal Motor Carrier Safety Administration jointly developed the MMUCC in collaboration with State and local agencies. 59 California, Florida, Iowa, Maryland, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Jersey, New York, Oklahoma, Oregon, Pennsylvania, Tennessee, and Texas. 60 61
Stutts, Reinfurt, Staplin, and Rodgman. Stutts, Huang, and Hunter.
Pennsylvania crash data62 for 1999 and 2000 indicated that 10,315, or 3.5 percent, of all traffic crashes involved citations for driver distractions. Using or dialing a wireless telephone accounted for 5.2 percent of driver distractions. The California Highway Patrol examined driver distraction and inattention accident data in California for the 6-month period from January 1 to June 30, 2002.63 The law enforcement agency found that 6 percent (5,677 of 491,083) of drivers in all accidents were inattentive. Of the accidents related to inattention, the largest category (611 of 5,677), or 11 percent, involved wireless telephones. According to Virginias accident records, 12.5 and 12.1 percent of drivers involved in accidents in 2000 and 2001, respectively, were inattentive at the time of the crash. A Virginia study64 examined driver distraction accidents from June 15 to November 30, 2002, in which the police had reported the type of distraction in driver inattention crashes. The study included information on 2,792 crashes involving 4,494 drivers, of whom 2,822 were distracted drivers. Driver fatigue or drivers who fell asleep accounted for 17 percent of the distractions reported, and wireless telephone use accounted for 3.9 percent. The Safety Board analyzed the 1991-2000 FARS data to identify driver distraction factors and utility vehicle65 involvement in accidents. Driver distraction factors, as coded under FARS and used in this analysis, included wireless telephones, fax machines, computers, on-board navigation systems, two-way radios, and heads-up displays. Distraction factors accounted for about 0.09 percent of the coded factors (553 of 601,002); wireless telephones accounted for 88.5 percent of the distraction factors (489 of 553). Driver distraction factors accounted for about 0.15 percent of the coded driver factors in both single-vehicle accidents involving a utility vehicle (38 of 28,140 coded driver factors) and all utility vehicle accidents (66 of 43,195 coded driver factors). Wireless telephone use accounted for all distraction factors in the single-vehicle accidents involving a utility vehicle and all but two of the coded distraction factors for utility vehicle accidents overall. Other Accidents Involving Wireless Telephone Use The Safety Board investigated three other 2002 accidents in support of the Largo accident investigation. All three involved drivers who were engaged in a wireless telephone conversation at the time of the accident.

Driver Distractions and Traffic Safety, Staff Report Pursuant to 2000 Senate Resolution No. 127, General Assembly of the Commonwealth of Pennsylvania, Joint State Government Commission, December 2001. California Highway Patrol, Driver Distractions and Inattention Data Summary, Report to the Governor and Legislature, November 2002.
64 Andrea L. Glaze and James M. Ellis, Pilot Study of Distracted Drivers, Center for Public Policy at Virginia Commonwealth University, Virginia, January 2003. 63
Utility vehicle categories are compact utility, large utility, utility station wagon, and utility unknown body type.
About 9:10 a.m. on April 11, 2002, a 1998 Chevrolet passenger car was traveling southbound on State Route 5 near Korona, Florida, when the driver lost control and the vehicle ran off the road, colliding with two trees.66 The unbelted 16-year-old driver, unbelted 14-year-old left rear seat passenger, unbelted 14-year-old center rear seat passenger (ejected), and unbelted 7-year-old right rear seat passenger (ejected) all sustained fatal injuries. The lap/shoulder-belted 6-year-old right front seat passenger sustained serious injuries. At the time of the accident, the Chevrolet was following another vehicle, and the accident driver was engaged in a wireless telephone conversation with that vehicles driver. About 8:08 a.m. on June 24, 2002, southbound Amtrak train 68 struck an eastbound 1996 Toyota Camry on the highway-rail grade crossing at Baseline Road near Little Rock, Arkansas.67 None of the 142 passengers and 11 crewmembers aboard the train sustained injures. The 44-year-old Toyota driver sustained fatal injuries. Witnesses reported that the crossing gates were down and that the Toyota driver was talking on a handheld wireless telephone as she approached the crossing, changed lanes to go around a stopped vehicle, and drove around the crossing gates into the path of the approaching train. Her wireless telephone records indicated that she had placed three calls between 8:02:31 a.m. and 8:08:01 a.m. About 7:13 p.m. on November 10, 2002, a 2002 Dodge Dakota pickup truck was traveling northbound on North Road, in Raymond Township, Illinois, when the vehicle failed to stop at a stop sign, entered the intersection with North 21st Avenue, and collided with an eastbound 1996 Freightliner tractor-semitrailer.68 The 55-year-old pickup truck driver sustained fatal injuries, and the tractor-semitrailer driver sustained minor injuries. Witnesses and wireless telephone records indicated that the pickup truck driver was engaged in a wireless telephone conversation at the time of the accident. Provisional or Graduated Licenses A provisional license system is a three-stage graduated licensing system comprising a learners permit; a provisional, probationary, or intermediate licensed period;69 and, eventually, full, unrestricted driving. The duration of time for the intermediate stage varies from State to State but is less than 2 years in all States. According to the Insurance Institute for Highway Safety,States, the District of Columbia, and 4 Canadian provinces have adopted three-stage graduated licensing systems. If certain conditions are violated under a provisional license system, the provisional license can be suspended or revoked or issuance of an unrestricted license can

which measures rotation of the vehicle around its vertical axis, monitors how quickly a vehicle is beginning to rotate, or spin out of control. The ESC computer algorithm then brings the vehicles actual path in line with the drivers intended path, unless the yaw acceleration is so severe that it cannot be corrected. ESC systems act by selectively applying braking force at the appropriate wheel to return the vehicle to driver control. For example, when a vehicle is beginning to spin out (oversteering), the ESC momentarily brakes the outside front wheel to straighten the vehicle and prevent spinning, and when a vehicle is not turning quickly enough for the drivers steer input (understeering), the ESC momentarily brakes the inside rear wheel to provide greater path curvature. (See figure 15.) In addition to selective brake control, some systems incorporate throttle control to reduce engine power, as necessary, and each system is tuned to the individual vehicle. The ESCs intervention requires no active driver participation, and most drivers do not realize that the ESC has intervened.
Figure 15. Detection of oversteer and understeer by the ESC system known as the electronic stability program (ESP). (Illustration courtesy of Continental Teves.)
According to the Electronic Stability Control Coalition, an organization of ESC manufacturers, the cost of installing ESC as standard equipment on vehicles ranges from $150 to $400 depending on the existing standard equipment ($350 to $400 for vehicles that do not have ABS, $250 to $300 for vehicles that have ABS, and $150 to $200 for vehicles that have ABS and traction control). Currently, 6 percent of vehicles produced in the United States have ESC. For the 2003 model year, most European passenger cars sold in the United States have ESC as standard equipment, and ESC is offered on many Japanese cars as optional equipment. ESC is also optional equipment on some Ford Motor Company and General Motors Corporation luxury models. Daimler-Chrysler Corporation recently completed an accident study that compared Mercedes products in European service equipped and not equipped with ESC systems.75 Researchers examined statistics from more than 1.5 million accidents that had been compiled by the German Government Statistics Office. They compared 1998-1999 accidents involving Mercedes models without ESC to 2000-2001 accidents involving Mercedes models with ESC. The results indicated a 15-percent reduction in overall accidents, a 10-percent reduction in rollover accidents, and a 12-percent reduction in the most serious injury accidents.

November 26, 2002, press release.

Analysis

General
This accident involved multiple risk factors, some of which are associated with young drivers. A 20-year-old, inexperienced, unbelted driver was operating a high-profile, short-wheelbase, sport utility vehicle, with which she was unfamiliar, 15 to 20 miles over the speed limit, while talking on a handheld wireless telephone. The driver encountered wind gusts, oversteered for a number of reasons that will be discussed below, and lost control. The vehicle yawed off the left side of the roadway, drove over an obsolete guardrail end treatment through a depressed median, hit the back of a guardrail, and vaulted into an oncoming minivan. This analysis first discusses the factors and conditions that the Safety Board was able to exclude as neither causing nor contributing to the accident. It then provides a brief overview of the accident events and a detailed discussion of the issues. The major safety issues identified were: the accident drivers speed, operating inexperience, and unfamiliarity with the vehicle; the use of a wireless telephone while operating a vehicle; the need for technology to aid vehicle stability; and the adequacy of the existing barrier system.

Exclusions

The accident drivers postaccident toxicological tests were negative for alcohol and drugs, and she appeared to have received adequate rest in the 72 hours before the accident. Postaccident inspection of the Explorer revealed no mechanical anomalies. The Safety Board specifically examined the Explorer components that could have contributed to the vehicles rapid swerving motion. Although severely damaged as a result of the accident, the steering and suspension apparatus showed no signs of preaccident defects. Likewise, the tires were closely examined. Although they too were severely damaged as a result of the accident, the tires showed no signs of preaccident shredding or tearing that would indicate tire failure. While accident damage prevented investigators from determining the pressure in three of the four tires, none of the tires exhibited wear due to low tire pressure prior to the accident. The Prince Georges County Fire Department was on scene within 7 minutes of notification. Therefore, the Safety Board concludes that the accident driver was not impaired due to alcohol, drugs, or fatigue; the mechanical condition of the Explorer did not contribute to the accident; and the emergency response was adequate and timely. Neither the driver of the Explorer nor the right front passenger of the Windstar was using the available restraint systems. However, the collision forces between the two
vehicles, as well as the occupant compartment intrusions for both vehicles, were severe. The Injury Assessment Reference Values found in 49 Code of Federal Regulations 571.208, Federal Motor Vehicle Safety Standard 208, indicate that in a 30-mph barrier crash, the typical forces occur in 85 to 100 milliseconds. These values further indicate that forces exceeding 60 gs (acceleration of gravity) on the chest, chest compression of more than 3 inches, a femur load of more than 2,250 pounds, and head injury criteria [HIC] above 1,000 are considered to exceed human tolerances. In this accident, the Explorers vault speed off the guardrail was at least 40 mph, and the Windstar was traveling between 80 and 90 mph. The closing speed in such circumstances would have been approximately 120 mph, the equivalent of a 60-mph barrier crash, or about twice as much as that required to exceed human tolerances. Furthermore, the Explorer collided with the Windstar while inverted and struck the Windstar in its windshield and A-pillar area, causing major intrusion of the occupant compartments. The Safety Board concludes that the collision forces and intrusion into the occupant compartments of both the Explorer and Windstar rendered the vehicles occupant spaces unsurvivable.

The Accident

Weather Conditions On the day of the accident, the NWS issued weather advisories warning of high wind conditions, including strong west to northwest winds expected into the evening hours. Wind speeds of 25 to 35 mph and wind gusts of up to 45 mph were predicted. About 10 minutes before the accident, Andrews AFB recorded winds of 23 to 24 mph and gusts of 39 mph from a heading of 310. These winds would have come from an angle about 35 to the left of the Explorer.76 Shortly thereafter, Andrews AFB recorded a wind gust of 44 mph from a heading of 300, about 45 to the left of the Explorers direction of travel. (See figure 16.) Additionally, a witness traveling behind the Explorer at the time of the accident described wind gusts that were sufficiently severe to cause him to reduce his vehicles speed. Therefore, the Safety Board concludes that at the time of the accident, the Explorer experienced strong winds, including potential gusts between 39 and 44 mph, from the left at an approximate angle of 35 to 45.
At the time of the accident, the Explorer was traveling at a heading of 355 magnetic or 345 true.

Northbound I-95/495

Wind direction
Figure 16. Explorers path from the northbound lanes through the median.
Collision Events The Explorer was proceeding northbound in the left lane of I-95/495, when it abruptly departed the roadway. A witness traveling behind the Explorer reported that the accident vehicle was traveling between 70 and 75 mph at the time. Shortly before the Explorer left the roadway, it probably encountered severe wind gusts from the left that would have pushed it to the right. Tire marks on the roadway indicated that a sharp swerve to the left preceded the vehicles departure from the roadway. Investigators found no mechanical anomalies that would account for the swerve. In response to the wind gust, which would have pushed the vehicle to the right, the driver apparently made a sharp steering maneuver to the left. This sharp steering maneuver was quite likely the culmination of several factors, as outlined below. Shortly before the accident, the driver made a wireless telephone call to her male friend and was talking on the telephone when the accident occurred. Since no hands-free devices were found with the telephone, the driver was probably holding the telephone in one hand and steering with the other hand at the time of the accident. Given the content of the telephone conversation as reported by the male friend, the driver was probably scanning the roadway ahead and searching for his vehicle, which was somewhere on the highway ahead of her. Therefore, not only did the cognitive process of the conversation probably distract her, but her attention was likely to have been redirected from the driving task to a searching task. As a result, when the Explorer encountered the wind gust, the driver was most likely not attending to the driving task, was instead focused on the conversation and a searching task, and was further hampered by physically holding the wireless telephone, which left only one hand for driving this unfamiliar vehicle. The driver, not expecting the wind gust that probably pushed her vehicle to the right, would have had to perceive what was happening and then react. Typical driver perception-reaction time77 ranges from 0.9 to 2.1 seconds78 and the 95th-percentile79 reaction time is 1.6 seconds. Previously noted research suggests that drivers may respond more quickly to crosswinds than to other driving tasks. Conversely, a drivers perceptionreaction time can be greater if other factors, including surprise, inexperience, and distraction, are present. Because the accident driver was distracted, may not have been expecting the wind gust, and was inexperienced, 1 to 2 seconds may have elapsed before she reacted to the wind gust. If she was driving 70 mph at the time of the wind gust, the driver may have traveled 100 to 200 feet before she reacted. Due to the lack of physical evidence, the Safety Board was unable to determine precisely how far the wind may have pushed the Explorer during this 1- to 2-second period; however, given the length of time and the velocity of the wind, the Explorer may have intruded into the adjacent lane. Because the driver was focused on the telephone

91 Vehicle stability, or the tendency to continue traveling in a straight line, is directly affected by the vehicle's wheelbase, or length between the front and rear axles. The greater the wheelbase, the less the vehicle is affected by wind perturbations or sharp steering inputs.
The simulation modeled a generic SUV that had a wheelbase similar to that of the accident vehicle; however, the ESC system applied was not specifically tailored to the vehicle model. Therefore, the results represent the minimum benefits of the ESC system.
The first comparison evaluated both vehicle models traveling straight at 70 mph with a driver-initiated quick left steering input, followed by a counter-steer to the right, then hard left steering, and, finally, quickly reducing the steering angle to zero, or straight. In this comparison, the standard SUV continued to sideslip and yaw at the end of the simulation, even though the driver steering input was straight ahead. This yawing and sideslip indicated that the vehicle was not yet under control or stable when the simulation ended. However, in the ESC-equipped vehicle, the sideslip and yaw velocities were zero at the end of the simulation, indicating that the stability control system brought the vehicle under control and that the vehicle was steering along the path intended by the driver. In the second comparison, the same type of steering maneuver was assumed (left steer, right steer, left steer); however the final steering input was modified to return the vehicle to its original path. The standard SUV was unable to regain its original path but instead crossed that path, and the sideslip increased and the vehicle yawed, indicating that the vehicle would be very difficult to control through steering alone. In contrast, the ESCequipped vehicle intersected its original path at a slight angle with essentially zero yaw velocity and sideslip, and the vehicle could be easily steered back onto that path. The simulations demonstrated that ESC systems can reduce sideslip and yaw in situations in which steering or lateral movements are encountered, allowing a driver to regain control of a vehicle. Additionally, the simulations showed that ESC may assist drivers of errant vehicles to not only regain control, but also return to their intended path. In both cases, the amount of time available to a driver to steer the under-control vehicle to avoid an accident increased significantly. Moments before the actual crash, the accident driver probably had the steering wheel positioned so that the Explorer would remain in its travel lane as the wind gust began pushing it to the right. Had the Explorer been equipped with ESC, once the vehicle was pushed to the right by the wind, and assuming the sideslip and yaw rotation associated with the path deviation to the right were great enough, the sensors would have signaled the ESCs computer that a correction was necessary to maintain the drivers intended path straight ahead. The ESC system would then have applied the appropriate braking to intervene and reduce the yaw acceleration, thereby greatly increasing the vehicles responsiveness to steering inputs. Such an ESC intervention may have been sufficient to allow the driver to maintain control of her vehicle. Following the wind gust, the driver probably attempted to steer sharply to the left, causing the vehicle to swerve off the road. As the Explorer departed the road, an ESC system would have been monitoring the vehicles rotational motion and in this situation, as in the wind gust situation, may have applied braking to compensate. Such an ESC intervention could have provided the driver with enough additional reaction-response time to steer her vehicle back onto the roadway. The Safety Board cannot conclusively determine the degree to which an ESC system might have affected either the vehicles initial reaction to the wind gust or the vehicles reaction to the drivers sharp, high-speed steering input. Detailed driver inputs, exact wind forces, and precise vehicle dynamics are unknown. Additionally, ESC system

5. 6. 7. 8. 9.

10. An electronic stability control system may have helped the accident driver maintain control of her vehicle during the Explorers initial response to the wind gust and during the subsequent reaction by the driver. 11. The barrier system in place at the accident site was ineffective because it failed to redirect the accident vehicle and prevent it from entering the opposing lanes of traffic. 12. The median barrier warrant guidance in the American Association of State Highway and Transportation Officials 2002 Roadside Design Guide is inadequate to cover todays high-speed, high-volume roadways.

Probable Cause

The National Transportation Safety Board determines that the probable cause of the February 1, 2002, collision of the Ford Explorer Sport with the Ford Windstar minivan and Jeep Grand Cherokee was the Explorer drivers failure to maintain directional control of her high-profile, short-wheelbase vehicle in the windy conditions due to a combination of inexperience, unfamiliarity with the vehicle, speed, and distraction caused by use of a handheld wireless telephone. Contributing to the severity of the accident was the lack of an effective median barrier at the accident site.

Recommendations

As a result of this accident, the National Transportation Safety Board makes the following safety recommendations:
To the National Highway Traffic Safety Administration: Develop, in conjunction with The Advertising Council, Inc., a media campaign stressing the dangers associated with distracted driving. (H-03-03) Develop, in conjunction with the American Driver and Traffic Safety Education Association, a module for driver education curriculums that emphasizes the risks of engaging in distracting behavior. (H-03-04) Determine the magnitude and impact of driver-controlled, in-vehicle distractions, including the use of interactive wireless communication devices, on highway safety and report your findings to the U. S. Congress and the States. (H-03-05) Expand your current evaluation of electronic stability control systems and determine their potential for assisting drivers in maintaining control of passenger cars, light trucks, sport utility vehicles, and vans. Include in this evaluation an accident data analysis of electronic stability control-equipped vehicles in the U.S. fleet. (H-03-06) If the results of your evaluation of electronic stability control systems are favorable, initiate a phased-in electronic stability control mandate for passenger cars, light trucks, sport utility vehicles, and vans. (H-03-07) To the 48 States that do not have legislation prohibiting holders of learners permits and intermediate licenses from using interactive wireless communication devices: Enact legislation to prohibit holders of learners permits and intermediate licenses from using interactive wireless communication devices while driving. (H-03-08) To the 34 States that do not have driver distraction codes on their traffic accident investigation forms: Add driver distraction codes, including codes for interactive wireless communication device use, to your traffic accident investigation forms. (H-03-09) To the American Driver and Traffic Safety Education Association: Develop, in conjunction with the National Highway Traffic Safety Administration, a module for driver education curriculums that emphasizes the risks of engaging in distracting behavior. (H-03-10)

Fuel Pump Replacement on a 2003 Sport Trac By: David Rheman This is how I changed the fuel pump on my 2003 Ford Explorer Sport Trac 4x2. This is for possible information ONLY! Anything I say or do here that causes you to say or do anything is completely at your own risk! Dont do something stupid just because I did it and may have gotten away with it so far! Tools: 13mm Socket for the tank strap bolts (but a worked as well) Ratchet Extensions (for the back bolt) Floor Jack Jack Stands Ramps Fuel line fitting release tool LARGE flat bladed screwdriver Mallet (I used a brass mallet, but almost any hammer will work) Parts: New Fuel Pump (Mine came from Ford, part #3L2U-9H307-EB) Re-use old fuel pump gasket and big plastic nut

Step 1.

Put the back of the truck up on ramps. Hopefully yours will do like mine did and will run for long enough to get it up there!

Step 2.

Put chocks under one of the front tires. Theres almost nothing worse than being under a car that starts rolling!

Step 3.

This is a picture of the bolt you will have to take out to release the front strap that holds the tank in. The other end of the strap fits into a slot in the frame, so one bolt is all you need to release the strap.

Step 4.

This is a picture of the bolt for the back strap. You will need a long extension or really skinny arms to reach past the driveshaft!

Step 5.

I used a rope from one side tie-down to the front of the bed and down past the driveshaft to the tank and back up again on the other side. The fishing pole helps fish the line back up the other side.

Step 6.

This really isnt a step, but here you can see where the rope goes underneath. The strap is already off in this picture. Please put the rope in place BEFORE you release the strap!

Step 7.

I used a jack stand to hold up the front. With a half a tank of gas it wasnt too bad, but I should have used a small board between the jack stand and the tank to distribute the weight better!

Step 8.

Partway down the tank suddenly wont go any farther. Youll have to reach up and unscrew the clamp to the filler neck hose attachment to the tank.

Step 9.

I took this picture to show the clips holding the fuel line to the tank. I released the clips to allow the fuel line to move away from the tank. I later realized its easier to release the lines from the fuel filter and take them out with the tank.

Step 10.

Here are the tank straps on the ground. You see the bolt on one end and the T on the other end that slips into a slot in the frame.

Step 11.

Heres the tank halfway down. Take it slow and easy, a little down on one end then a little down on the other end. Keep an eye on the vent hoses so you can pull them loose when you can get to them. Now is a good time to find the wire to the pump and release it from its socket, which is against the frame crossmember.

Step 12.

Here is the tank on the ground!

Step 13.

Here is the tank out of the truck! Now you can release the fuel lines from the fuel pump. These used the same fittings that attach to the fuel filter, so the same tool should work.

Step 14.

This is the top of the fuel pump. You will need to unscrew the big grey ribbed ring to get the pump out. I found that a large flatbladed screwdriver against the ribs of the nut worked ok to get the nut to turn. I used a brass mallet to smack the end of the screwdriver. It took some work to get it going, but it finally started moving.

Step 15.

This is why I had trouble finding the right pump. My old pump had five pins in the electrical socket, and all the aftermarket pumps had four pins! And all said Its yours if you hook it up! No returns on installed electrical items! Autozone had a five pin pump shown, but they had to order it from out of state! I finally got the number off the old pump and had a friend at a Ford dealership chase it down. It turns out the four pin pump supercedes the five pin pump! He got me a good price, too! I didnt even know he worked there! Ask your friends if they work at Ford!

Step 16.

Here is the new, four pin connector.

Step 17.

Here is the old pump.

Step 18.

Here is the new pump. Looks a lot better, doesnt it?

Step 19.

Here is a picture of the fittings on the fuel filter end. They look the same as the fittings on the pump end. I didnt think so at first, so I tried other ways to remove the fittings, and wound up messing up one of the fittings. Use the same method to remove the fittings from the pump that you use to remove the fittings from the filter!

Step 20.

Here is the new pump installed in the tank. The big plastic nut takes a little patience and work to get it lined up and threaded right. Find the start of the threads on the nut and the start of the threads on the tank and set them into each other, then push the other side of the nut down until its level. Then start threading the nut onto the tank. It should go by hand until snug, then use the mallet and screwdriver again to seat it tightly.

Step 21.

Those of you with sharp eyes may have noticed that the last picture showed a slightly modified clip for the fuel line! I wound up busting the larger one before I realized it was the same as the fuel filter clip. I tried all the parts stores I could think of on a late Saturday, but none of them carried that clip! So I shoved the line onto the pump, stuffed the remaining part of the clip into the slot and around to the back, and it seemed to hold. I knew it wouldnt stay there, so I threaded a zip-tie around the clip and through the holes in the fitting. It keeps the clip from rotating, and it ought to stay, but well see!

Step 22.

Here is the finished tank, ready to go back in the truck! Take your time getting it back up in there, but it really isnt all that hard. The rope trick used to let it down doesnt work very well to lift it back up, but it does help to keep the tank from falling if it slips off the jack. Use a board on a floor jack to lift it a little at each end. Use the rope to hold it at the back and the jack stand to hold it at the front, and back and forth until its in! Dont forget to hook up the vent hoses, filler hose, and electrical connector before the tank is all the way up! Use dielectric grease inside the connector to keep moisture out of the connection.
Step 23. (No Picture) When you fire it up, remember that the lines are empty and need to refill and re-pressurize before it will start, so give it a minute with the key in the on position before you try to start it. If it doesnt start on the first try, give it a minute more. Mine took three tries before it would start! Afterword: Theres more to the story. Two days after changing the pump, my Trac died on the way to work. On a whim, I reached under the dash and pushed the button for the fuel cutoff switch, which is the switch that cuts power to the pump in an accident. It fired right up! I headed home, and she died twice more before I got there, but pressing the switch fixed it each time. When I got home, though, I found that the switch had melted the connector! So the switch was the problem all along, not the pump. But you got a project out of it, didnt you?