Lauren Meredith

Further Development of Motorcycle Autonomous Emergency Braking (MAEB), What Can In-Depth Studies Tell Us? A Multinational Study

Objective: In 2006, Motorcycle Autonomous Emergency Braking (MAEB) was developed by a European Consortium (Powered Two Wheeler Integrated Safety, PISa) as a crash severity countermeasure for riders. This system can detect an obstacle through sensors in the front of the motorcycle and brakes automatically to achieve a 0.3 g deceleration if the collision is inevitable and the rider does not react. However, if the rider does brake, full braking force is applied automatically. Previous research into the potential benefits of MAEB has shown encouraging results. However, this was based on MAEB triggering algorithms designed for motorcycle crashes involving impacts with fixed objects and rear-end crashes. To estimate the full potential benefit of MAEB, there is a need to understand the full spectrum of motorcycle crashes and further develop triggering algorithms that apply to a wider spectrum of crash scenarios. Methods: In-depth crash data from 3 different countries were used: 80 hospital admittance cases collected during 2012–2013 within a 3-h driving range of Sydney, Australia, 40 crashes with Injury Severity Score (ISS) > 15 collected in the metropolitan area of Florence, Italy, during 2009–2012, and 92 fatal crashes that occurred in Sweden during 2008–2009. In the first step, the potential applicability of MAEB among the crashes was assessed using a decision tree method. To achieve this, a new triggering algorithm for MAEB was developed to address crossing scenarios as well as crashes involving stationary objects. In the second step, the potential benefit of MAEB across the applicable crashes was examined by using numerical computer simulations. Each crash was reconstructed twice—once with and once without MAEB deployed. Results: The principal finding is that using the new triggering algorithm, MAEB is seen to apply to a broad range of multivehicle motorcycle crashes. Crash mitigation was achieved through reductions in impact speed of up to approximately 10 percent, depending on the crash scenario and the initial vehicle pre-impact speeds. Conclusions: This research is the first attempt to evaluate MAEB with simulations on a broad range of crash scenarios using in-depth data. The results give further insights into the feasibility of MAEB in different speed ranges. It is clear then that MAEB is a promising technology that warrants further attention by researchers, manufacturers, and regulators.

Distribution and Type of Crash Damage to Motorcyclists’ Clothing: Validation of the Zone Approach in the European Standard for Motorcycle Protective Clothing, EN13595

Objective: Though the use of protective clothing reduces the risk of injury for motorcycle riders, not all protective clothing performs the same in crashes. A European Standard for motorcycle protective clothing (EN13595) was released in 2002 that specifies 4 zones in motorcycle clothing with different levels of protective qualities and 4 different test methods for assessing damage resistance. This project examined damage location and type in clothing worn by riders following a crash to establish the distribution of impact points and validate the zones described in EN13595. Method: Data from 117 crashed motorcycle riders collected during crash investigation were examined. These data included medical data and clothing inspections and contained 576 cases of clothing damage. To ensure that the impact point distribution included all possible contact locations, an additional 433 distinct injury locations were examined where injury had occurred but clothing was either undamaged or not present at that location. Descriptive techniques were used in the analysis. Results: The majority of damage occurred in areas covering the extremities or pelvic girdle (93%), with most occurring on the wrists and hands (18%) and ankles and feet (18%). Clothing regions covering the shoulder (10%), forearm (10%), elbow (9%), thigh (7%), lower leg (6%), and pelvic–hip region (5%) were also frequently damaged. Other body regions contributed only 8 percent of damage seen. Analysis of distinct injury locations demonstrated a similar distribution of impact. The most common types of clothing damage were abrasion, accounting for 69 percent, and torn material, which accounted for 26 percent of all damage. Further, the majority of material abrasion and tearing occurred in regions corresponding to zone 1, followed by zones 2, 3, and then 4. There were very few instances (3%) of burst and cut damage. Conclusions: The results are in agreement with the general concept of the zones used in the EU Standard. However, these results indicate that minor adjustments may be warranted. In particular, the number of impacts to the forearm and lower leg suggest that these regions might be better protected by considering the whole regions as zone 1or 2 rather than the multiple regions as currently indicated in the EU Standard. However, the subjective nature of determining the zone in which damage (and/or injury) occurred limits these findings and any others that attempt to validate the zone principles using real-world data. Further validation requires consideration of the severity of impact at different zones.

Motorcycle fuel tanks and pelvic fractures: A motorcycle fuel tank syndrome

ABSTRACT Objective: Pelvic injuries are a serious and commonly occurring injury to motorcycle riders involved in crashes, yet there has been limited research investigating the mechanisms involved in these injuries. This study aimed to investigate the mechanisms involved in pelvic injuries to crashed motorcyclists. Method: This study involved in-depth crash investigation and 2 convenience-based data sets were used. These data sets investigated motorcycle crashes in the Sydney, Newcastle, and Adelaide regions. Participants included motorcycle riders who had crashed either on a public road or private property within the study areas. The mechanism of injury and the type of injuries were investigated. Results: The most frequent cause of pelvic injuries in crashed motorcyclists was due to contact with the motorcycle fuel tank during the crash (85%). For riders who had come into contact with the fuel tank, the injury types were able to be grouped into 3 categories based on the complexity of the injury. The complexity of the injury appeared to increase with impact speed but this was a nonsignificant trend. The pelvic injuries that did not occur from contact with the fuel tank in this sample differed in asymmetry of loading and did not commonly involve injury to the bladder. They were commonly one-sided injuries but this differed based on the point of loading; however, a larger sample of these injuries needs to be investigated. Conclusion: Overall improvements in road safety have not been replicated in the amelioration of pelvic injuries in motorcyclists and improvements in the design of crashworthy motorcycle fuel tanks appear to be required.

Energy attenuation performance of impact protection worn by motorcyclists in real-world crashes

ABSTRACT Objective: Laboratory studies have demonstrated that impact protectors (IP) used in motorcycle clothing can reduce fracture severities. While crash studies have reported IP are associated with reduced likelihood of soft tissue injury, there is little evidence of their effectiveness in reducing fracture likelihood. This discrepancy might be related to IP quality. There are mandatory requirements for IP supplied with protective clothing in Europe, but not elsewhere. This study examines the energy attenuation performance of IP used by Australian riders. Methods: IP were harvested from clothing worn by crashed riders admitted to hospital. The IP were examined and energy attenuation properties were determined using EN 1621-1 test procedures. Impact injury was identified from medical records and defined as fractures, dislocations, and avulsions that occurred following impact to the riders shoulders, elbows, hips, and/or knees. Fishers exact test was used to examine the relationship between meeting the EN 1621-1 energy attenuation requirements and impact injury. The association between the average and maximum transmitted force, and impact injury was examined using generalized estimating equations. Motorcycle riders were recruited as part of an in-depth crash study through three hospitals in New South Wales, Australia, between 2012 and 2014. Riders were interviewed, and engineers conducted site, vehicle, and clothing inspections. Clothing was collected, or identical garments were purchased. Results: Clothing was inspected for 62 riders. Of these, 19 wore clothing incorporating 76 IP. Twenty-six of these were impacted in the crash event. Almost all impacted IP (96%) were CE marked, and most (83%) met Level 1 energy attenuation requirements of EN 1621-1 when tested. Of the 26 impacted IP, four were associated with impact injuries, including midshaft and distal clavicle fractures and a scapula and olecranon fracture. No associations between meeting EN 1621-1 requirements and impact injury were found (p = 0.5). There was no association between average force transmitted and impact injury (95% CI: 0.91–1.24); however, as maximum force transmitted increased, the odds of impact injury increased (95% CI: 1.01–1.2). These results indicate a high probability of impact injury at 50 kN, the limit of maximum transmitted force specified in EN 1621-1. Conclusion: The allowable transmitted force of EN 1621-1 may be too high to effectively reduce the probability of impact injury. This is not surprising, given human tolerance levels that are reported in literature. Reducing the force limit below the reported fracture tolerance limits might be difficult with current technology. However, there is scope to reduce the EN 1621-1 maximum limit of 50 kN transmitted force. A reduction in the maximum force limit would improve rider protection and appears feasible, as 77% of tested IP recorded a maximum force <35 kN. This level of transmitted force is estimated to be associated with <20% probability of impact injury. While the performance of IP available to Australian riders is not regulated, most IP was CE marked. The results indicate a significant association between maximum transmitted force, tested according to EN 1621-1 procedures, and impact injury. Further investigation of the EN 1621-1 requirements may be warranted. This work will interest those targeting protective equipment for motorcyclists as a mechanism for reducing injury to these vulnerable road users.

Validation of the Abrasion Resistance Test Protocols and Performance Criteria of EN13595: The Probability of Soft Tissue Injury to Motorcycle Riders by Abrasion Resistance of Their Clothing

INTRODUCTION Motorcyclists represent an increasing proportion of road users globally and are increasingly represented in crash statistics. Soft tissue injuries are the most common type of injuries to crashed motorcyclists. These injuries can be prevented through the use of protective clothing designed for motorcycle use. However, the quality of such clothing is not controlled in many countries around the world. A European Standard was developed to assess the performance of clothing but as this is not mandatory, clothing certified to this Standard is difficult to obtain. Given the importance of this Standard, and that it has been validated only once, further validation work is required. METHODS In-depth crash investigation data were used to investigate the relationship between the abrasion resistance performance of clothing and real-world injury outcome. Clothing was collected from riders who crashed on public roads in Sydney and Newcastle, Australia. This clothing was tested according to the EU Standard and the time to hole was recorded. Hospital medical records were reviewed and the association between a rider suffering a soft tissue injury and the time-to-hole for the garment was examined. RESULTS The probability of soft tissue injury for Level 1 Standard garments was between 40-60%, but more than 60% of garments tested failed to meet the minimum requirement. CONCLUSIONS The findings of this study provide qualified support for the Standard, with a marginal association between time-to-hole and injury being found. PRACTICAL IMPLICATIONS This work supports the need for improved safety performance and an increased number of high performing garments being available to motorcyclists.