Can a Vehicle Involved in a Rollover Be Insured Again

• Journal List
• Ann Adv Automot Med
• five.52; 2008
• PMC3256771

Ann Adv Automot Med. 2008; 52: 9–22.

A Comprehensive Review of Rollover Accidents Involving Vehicles Equipped with Electronic Stability Control (ESC) Systems

Abstruse

This written report investigated 478 law accident reports from ix states to examine and characterize rollover crashes involving ESC-equipped vehicles. The focus was on the sequence of critical events leading to loss of command and rollover, and the interactions between the blow, driver, and surroundings. Results show that, while ESC is effective in reducing loss of control leading to certain rollover crashes, its effectiveness is diminished in others, peculiarly when the vehicle departs the roadway or when environmental factors such equally slick road conditions or driver factors such as speeding, distraction, fatigue, impairment, or overcorrection are present.

INTRODUCTION

This study addresses the effectiveness of Electronic Stability Control (ESC) systems using field accident data. A contempo review of bachelor field data on crash-involved ESC-equipped vehicles indicated that ESC is highly effective for rollovers in which the rollover is the offset harmful event (Padmanaban, 2007). Nonetheless, that study also showed that ESC is not nearly equally effective for other types of rollover crashes (Padmanaban, 2007). To farther investigate this finding, the present written report made a detailed review of police force accident reports of unmarried-vehicle rollovers involving vehicles with ESC installed as standard equipment ("ESC vehicles"). In improver to the information coded in state accident information bases, narrative descriptions and scene diagrams were examined to identify factors associated with rollovers involving ESC vehicles.

Past Studies

Every bit defined in Federal Motor Vehicle Safety Standard 126, ESC systems "utilize automated estimator controlled braking of private wheels to assist the commuter in maintaining control in disquisitional driving situations in which the vehicle is beginning to lose directional stability at the rear wheels (spin out) or directional control at the front wheels (plough out)" (NHTSA, 2007)

By 2011, the standard volition require such systems in light vehicles to:

• □ Monitor or approximate driver steer input, yaw, side slip and/or side slip rate.

• □ Employ a figurer algorithm to apply brake torque at individual wheels to produce a cosmetic yaw moment.

• □ And thereby limit oversteer (spin out) and understeer (plough out).

While there are numerous systems, operating under diverse names, any system referred to in this newspaper every bit "ESC" meets the definition provided above. Systems built past various manufacturers monitor dissimilar vehicle dynamic parameters and may include other interventions too (such every bit reduction in engine torque).

Over the past decade, various studies have suggested that ESC systems are constructive in reducing crashes; nevertheless, about of these studies evaluated very few vehicles (mostly luxury models, since these were the first to be equipped with ESC systems) and used limited crash data and/or vehicle types (generally cars and SUVs). Mercedes-Benz (2006) examined the effectiveness of their proprietary ESC organization in their passenger cars in Germany; Aga and Okada (2003) included only 3 Toyota passenger car models, involved in traffic accidents in Japan; Prevarication (2005) included more vehicle model serial than either the Toyota or Mercedes studies, just focused on cars but. A recent study of 50,000 accidents in Britain covered more types of crashes and conditions; in that written report, ESC effectiveness was estimated to exist seven% for all collisions, 25% for fatal collisions, and 36% for rollover events (Thomas and Frampton, 2007).

Several The states studies covered a greater multifariousness of vehicles and crashes, but came to differing conclusions. Farmer's (2004) Insurance Institute for Highway Condom study looked at police-reported crashes (all crash types) in vii states over a two-year period, and fatal crashes in the United states over a three-twelvemonth period, for cars and sport utility vehicles (SUVs) and credited ESC systems with a 41% reduction in all (and a 56% reduction in fatal) single-vehicle crashes, but institute reductions for multiple-vehicle crashes to be insignificant. A Pacific Institute for Enquiry and Evaluation study found a 53% reduction in single-vehicle crashes, and a 12% reduction in multiple-vehicle crashes, involving low-cal vehicles (Bahouth, 2005).

A University of Michigan Transportation Enquiry Plant (UMTRI) study examined cars and SUVs separately for crashes "generally associated with loss of control" (Green and Woodrooffe, 2006). The UMTRI study used Full general Estimates System (GES) files to examine all crashes and Fatality Analysis Reporting System (FARS) data to examine fatal and fatal rollover crashes. The study estimated ESC systems would reduce odds of fatal rollover crashes past twoscore% for cars and 73% for SUVs. A simulator-based written report of 120 subjects in loss-of-control situations with and without ESC systems (Papelis et al., 2004) expressed a more positive view of the system's usefulness in reducing crashes. That study found ESC systems offered an 88% reduction in loss of control, and its authors concluded that: "In all cases, there was a do good to having the system" (Papelis et al., 2004).

The National Highway Traffic Safe (NHTSA) ESC report (Dang, 2006) examined constabulary-reported crash data from vii states and institute ESC to be effective in reducing single-vehicle "run-off-road" crashes by 46% for rider cars and 75% for light trucks. The NHTSA study also evaluated FARS data for 1997 to 2004 model year passenger cars and light trucks and found ESC systems to be effective in reducing fatal single-vehicle "run-off-road" crashes by 35% for passenger cars and 72% for light trucks. This written report was subsequently updated to include more recent field information and the conclusions were consistent with their earlier study (Dang, 2007).

A study done by JP Research (Padmanaban, 2007) showed that ESC systems were highly effective for fatal single-vehicle rollovers in which the rollover was the first harmful event. For light trucks, ESC was not significantly effective for single-vehicle rollovers where the showtime harmful events included collision with tree/pole/post/guardrail/culvert or ditch/beach. These types of rollover crashes were primarily off-road rollover crashes, and NHTSA'southward study did not examine the effectiveness of ESC in reducing such rollover crashes.

To better understand factors relating to rollovers involving vehicles with ESC systems, it was deemed appropriate to perform a comprehensive review of field data. Hence this study.

Current Study

As indicated, a comprehensive review was fabricated of police accident reports for 478 single-vehicle rollover crashes involving vehicles equipped with ESC systems. The objectives were to examine and characterize rollover crashes involving ESC-equipped vehicles in greater particular than is possible using but the coded information bachelor in state and FARS databases. This included review of engineering science bug that chronicle to ESC effectiveness. In particular, the sequence of critical events leading to rollovers and the interactions betwixt the blow, driver, and environment were examined for ESC vehicles.

METHODS

Vehicle models with ESC systems every bit standard equipment were identified using multiple publicly bachelor sources and information from vehicle manufacturers. The study included single-vehicle rollover crashes from the state accident data files, and difficult copies of police reports containing accident narratives were obtained. A detailed coding of accident scenarios was performed past an engineering team. The coding effort incorporated 47 variables, including those for critical events (departure from route, loss of directional control, impact with an object, and driver'southward input); commuter factors (impairment, speeding, inattention, distraction, fatigue, and overcorrection); and environmental factors. Finally, an technology review was undertaken to provide insights into several accident scenarios in which ESC was not highly effective in preventing rollovers.

Vehicle Nomenclature

Vehicle models with ESC systems were identified using the NHTSA Safercar.gov website, the Insurance Institute for Highway Safety website, MSN Automobile, and information from vehicle manufacturers.

Blow Information

For the study, all police blow reports for single-vehicle rollover crashes involving 1997–2006 model year vehicles equipped with ESC equally standard equipment were requested from 9 states (Alabama, Florida, Idaho, Kansas, Maryland, Missouri, Nebraska, Washington, and Wyoming). These states include a selection of the ecology and demographic conditions bachelor throughout the land. Law coded fields were examined for consistency beyond the states, and standardized coding fields were adult for the study.

Of the 507 reports received, 29 accidents were excluded due to the fact that ESC was not standard equipment or the crash was non a SVA rollover. Consequently, the study included 478 single vehicle rollovers.

Arroyo

Two specific objectives of this study were to use detailed data from police reports to (1) identify factors (including commuter, vehicle, and environmental factors) associated with the single-vehicle rollovers in this study and (two) make up one's mind critical events leading to those rollovers. Major factors associated with unlike blow scenarios were examined.

Detailed instructions were developed for variables to be coded from the law reports. These included variables that place:

• □ the sequence of critical events, such as divergence from roadway (with or without driver input), and loss of directional control (vehicle is not following the directional path commanded by the commuter)

• □ driver actions or decisions (such as speeding, booze interest, failure to stay in lane, overcorrection, or fatigue/inattention/lark) that could have influenced crash occurrence/outcome

• □ features of the crash environment (such equally conditions, roadway features and surface condition, and lighting) that might have influenced crash occurrence/outcome.

Procedures were adult to code variables in a consistent format suitable for input to statistical and engineering science analysis. Some variables, such as identifying occurrence of skidding, yawing, or driver overcorrection were coded for their occurrence at any time during the accident. Other variables examined chronologically immune structure of the critical consequence sequence leading to each of the rollovers. Examples of disquisitional event sequences include:

• □ Vehicle departure from road; steering; reentering road; second departure from road

• □ Loss of directional control; difference from road; impact

• □ Loss of directional command; steering; braking; skidding; deviation from road.

Table 1 (Appendix B) provides a detailed description of all codes used to identify critical events and other factors.

RESULTS

Factors Contributing to ESC Rollovers

Critical Sequences

Review and assay of the 478 police accident reports resulted in four primary categories of single-vehicle rollovers for ESC vehicles, as shown in Figure 1 (Appendix A):

1. 30% (143) of ESC vehicle rollovers involved departure from roadway without any driver input and prior to loss of directional command.

2. iii% (13) involved impacting an object without driver input prior to either road divergence or loss of directional control.

3. 31% (148) experienced loss of directional control prior to bear upon or route departure.

4. 26% (122) departed the route with possible commuter input. The records for an additional 52 crashes (11%) did not have enough information to categorize.

The vehicles in the beginning and 2nd categories that departed the road or impacted without driver input were at risk prior to the opportunity for ESC engagement.

For the 143 cases involving difference without driver input (starting time category), the subsequent critical events in the rollover crash sequences were examined, as shown in Figure ii. It was found that:

• □ 53% (76) impacted or rolled over

• □ 27% (39) reentered road

• □ 17% (24) experienced loss of directional control

• □ 3% (4) experienced some other event.

For the 39 vehicles that reentered the road, xc% involved steering overcorrection and the vast bulk (31) experienced a 2d departure from road (Figure 3). Twenty viii of these 31 experienced loss of control before the 2d divergence.

The 148 cases in the third category involved a loss of directional control prior to affect or route divergence. This ways the vehicle, while on the road, was yawing or rotating such that it did not follow the intended path commanded by the driver (based on narrative descriptions and scene diagrams). Subsequent rollover occurred either on or off the road.

Of the 122 cases in the fourth category (parting the route with possible driver input), 47% (57) of the instance records included information indicating drivers had attempted to steer or brake prior to road departure. The vehicles in this category demonstrate that, in spite of drivers' attempts to command their ESC-equipped vehicles, these vehicles may nonetheless depart the road and curl over.

Driver Factors

Figure 4 presents commuter-related factors associated with ESC vehicle rollovers. Speeding clearly dominates as the most frequent driver factor and was involved in xl% of all the rollovers. Fatigue/inattention/distraction is also prominent and was institute present in 29% of the single-vehicle rollover events. Overcorrection and booze impairment were also pregnant factors for rollovers involving ESC vehicles, with overcorrection present in 22% of the rollovers and alcohol impairment present in 21% of the rollovers.

For the two virtually common critical result categories (departure from roadway without commuter input and loss of directional command), driver factors contributing to rollovers were somewhat different. For events in which vehicles departed the road without driver input, fatigue/inattention/distraction dominated the listing, with speeding next (Figure 5A). When the outset critical event was loss of directional command, speeding was the dominant contributing gene and fatigue/inattention/distraction was next (Figure 5B). These values testify fatigue, distraction, and inattention to be (together) a more mutual factor for those cases in which a vehicle departs the road without driver intervention, and speeding to be a more common factor in loss of command accidents.

Environmental Factors

The role of environs, too, was shown to be important (Figure 6). In 47% of the accidents where the first critical event was loss of directional command, the pavement was slippery (either icy or wet). This is consistent with the fact that maximum braking forces (either practical through the pedal or ESC intervention) are diminished past low coefficient surfaces and, hence, ESC will have less stabilizing capacity. In contrast, 90% of the accidents with divergence from route as the first disquisitional outcome took place on dry roads.

DISCUSSION

Although many of the studies of ESC report high percentages of effectiveness, it is clear that numerous rollover accidents however occur for ESC vehicles. This study considered rollover accidents for ESC vehicles only, thus direct comparisons of ESC and non-ESC feel could not be quantified. However, analyses of those events for which ESC did not forestall rollover were still possible. This study showed that many ESC rollover cases involve situations where ESC has footling or no reason or opportunity to finer arbitrate, or where its intervening brake and throttle controls are limited past the bachelor friction at the tire/road interface.

In three% (thirteen) of the cases examined for this study, the vehicles rolled due to impact that occurred prior to either loss of directional control or departure from the road. Another 16% (76) impacted or rolled over subsequently departure from road with no driver input or known loss of directional control that might have engaged the ESC system. Hence in xix% (89) of the studied cases, ESC would not have been called upon to arbitrate until after impact. Conspicuously, ESC has no effectiveness if it is not engaged, and unlikely effectiveness subsequently significant impact forces, whether bear upon occurs on or off the road.

More often than not, vehicles that depart the road without driver input are "tracking" (non yawing out of control) equally they leave the road. Once off the road, the risk of control loss and rollover is compounded by two factors:

1. Driver surprise or anxiety apparently stimulates overcorrective steering maneuvers, which can induce specially loftier yaw moments. This is amplified when tires differentially engage relatively high-coefficient road surfaces and low-coefficient shoulders and off-road surfaces.

2. Off-road surfaces are more likely to be irregular, sloping, have areas of soft earth or hazards that can provide momentary and unpredictable yaw forces that would be difficult to avoid or compensate for, and are more likely to have tripping hazards known to trigger rollover (Viano and Parenteau, 2003).

Factors such as these would explicate the continued occurrence of loss of command and rollover for those vehicles departing the route without driver input.

The 122 vehicles that departed the route afterward possible driver braking, steering, or change in throttle control were subject to the same two gamble factors described above. This category included 46 cases with known driver input and no loss of directional control prior to departure from road; of these there are likely to be some for which ESC was engaged and loss of directional control was successfully avoided prior to route difference. Nevertheless, in the presence of the 2 off-road chance factors, rollover occurred later in the sequence. Likely to be included in this set would be some cases for which ESC was able to preclude loss of directional control only was unable to maintain the driver'southward chosen path on the road. Of course, ESC is unable to choose the most prudent path for safety, regardless of its effectiveness for maintaining the driver's chosen path.

Of the 478 total cases, 55% (265) involved departure from the road prior to known loss of directional command and despite the presence of ESC. The boosted gamble of rollover after road difference is not currently considered in NHTSA's development of vehicle tests that characterize rollover potential (Forkenbrock et al., 2003). Given the variability of off-road conditions, designing such tests would be difficult. Yet, these results testify that road-departure conditions are clearly important, and ESC is unable to eliminate off-road excursions and rollovers.

All 148 cases in which directional control was not maintained involved accidents in which ESC date was likely. Of the 122 where the vehicle departed the road with possible driver input, 57 involved the vehicle leaving the road with known driver input. It is likely that many of these besides involved ESC activation. Consequently, 43% (205) of the cases had still resulted in rollover despite probable ESC activation.

Commuter factors of fatigue, inattention, or lark; speeding; and steering overcorrection, as well as commuter impairment from alcohol or drugs, were clearly associated with these rollover accidents.

CONCLUSIONS

While ESC is effective in reducing loss of command in certain situations probable to lead to rollover crashes, its effectiveness is diminished in others, especially when the vehicle departs the roadway or when environmental factors such every bit slick road weather condition or driver factors such as speeding, fatigue/lark/inattention, booze/drug damage, or over-correction are present.

Conclusions regarding types of rollover accidents for vehicles with ESC equally standard equipment include:

• □ For about thirty% (143) of rollovers, the first critical event was departure from road without commuter input (i.due east., before ESC was engaged).

• □ Some other 31% (148) of rollovers occurred when loss of directional control took identify before the vehicle departed the road.

• □ About 26% (122) of rollovers occurred when vehicles departed the route after possible commuter input.

• □ Well-nigh 55% (265) of rollovers involved departure from the road prior to loss of directional control or rollover.

• □ About 43% (205) had probable ESC engagement, only however rolled.

Conclusions regarding driver factors include:

• □ For those cases where ESC vehicles reenter road prior to rollover, 90% of drivers imparted steering overcorrection and 80% of the vehicles departed the route again

• □ Speeding, fatigue/lark/inattention, overcorrection, and alcohol involvement were predominant driver factors associated with these rollovers.

  • – For divergence from road events: fatigue/lark/inattention, and overcorrection were predominant.

  • – For loss of directional control events: speeding was predominant.

• □ For all of these rollovers, alcohol involvement was besides identified as a pregnant contributing factor (21%).

Conclusions regarding ecology factors include:

• □ Environmental factors such every bit snowy/icy/wet route conditions were significant factors for loss of directional control events.

FUTURE WORK

The electric current report examined single-vehicle rollover accidents that occurred with ESC vehicles. A similar review and analysis of vehicles without ESC installation is underway. The purpose of that study is to allow comparisons and contrasts to farther explain ESC performance based on differences in frequencies of road departure, loss of directional control, feel on wet and icy roads, and driver demographics for ESC and non-ESC vehicles.

Appendix A: Figures

Figure 1

Primary Categories of Single-Vehicle Rollovers for ESC Vehicles

Figure 2

Critical Events Post-obit Road Departure Without Driver Input

Figure three

Vehicles Reentering Road After Departure Without Driver Input

Figure iv

Driver Factors Contributing to Single-Vehicle Rollovers of ESC Vehicles

Figure 5A

Driver Factors for Departure from Road without Driver Input (143)

Figure 5B

Driver Factors for Loss of Directional Command (148)

Figure 6

Comparisons of Roadway Conditions

Appendix B: Variables Coded for ESC Police Accident Report Analysis

1. Sharp Elevation Alter

2. Critical Event (upwards to 10)

3. Critical Outcome Text (upward to ten)

4. Departed Road (upwardly to ten)

5. Departed Route Text (up to 10)

6. Departure from Route (accident level)

7. Driver Factor Description (up to 4)

8. Divided Road

9. Driver Lark Inattention

10. Driver Distraction Inattention Text

11. Grade of Road

12. Lighting Conditions

13. Loss of Control Consequence Clarification

14. Loss of Path Control (up to x)

15. Loss of Path Control Basis (upward to 10)

16. Number of Lanes in Travel Direction

17. Object Impacted (upward to ten)

18. Object Impacted Text (upwardly to 10)

19. Object Surface Tripped Upon

20. Object Surface Tripped Upon Text

21. Overcorrection During Blow

22. Pre Event Movement

23. Pre Event Motility Text

24. Quarter Roll Description

25. Quarter Rolls

26. Reenter Road

27. Study Number

28. Roadway Alignment

29. Roadway Surface

30. Roadway Surface Status

31. Roadway Surface Condition Text

32. Rollover Initiation Location

33. Rollover Initiation Type

34. Rollover Initiation Blazon Text

35. Rollover Blazon

36. Shoulder Configuration

37. Shoulder Surface

38. Skidding During Blow

39. Speed Limit

40. Surface Status

41. Time of Twenty-four hours

42. Vehicle Left Road Prior to Rollover

43. Vehicle Defect

44. Vehicle Pulling Trailer

45. Weather Conditions

46. Weather Conditions Text

47. Yawing During Accident

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Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256771/

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