Vehicle front-end geometry and in-depth pedestrian injury outcomes

OBJECTIVE

Large passenger vehicles have consistently demonstrated an outsized injury risk to pedestrians they strike, particularly those with tall, blunt front ends. However, the specific injuries suffered by pedestrians in these crashes as well as the mechanics of those injuries remain unclear. The current study was conducted to explore how a variety of vehicle measurements affect pedestrian injury outcomes using crash reconstruction and detailed injury attribution.

METHODS

We analyzed 121 pedestrian crashes together with a set of vehicle measurements for each crash: hood leading edge height, bumper lead angle, hood length, hood angle, and windshield angle.

RESULTS

Consistent with past research, having a higher hood leading edge height increased pedestrian injury severity, especially among vehicles with blunt front ends. The poor crash outcomes associated with these vehicles stem from greater injury risk and severity to the torso and hip from these vehicles' front ends and a tendency for them to throw pedestrians forward after impact.

CONCLUSIONS

The combination of vehicle height and a steep bumper lead angle may explain the elevated pedestrian crash severity typically observed among large vehicles.

Bicyclist crashes with cars and SUVs: Injury severity and risk factors

OBJECTIVE

The popularity of bicycle travel has increased in recent years alongside a comparable increase in the risk of injury or death for those cyclists. The current study was conducted to investigate the differences in injury outcomes between bicyclists struck by SUVs and those struck by cars and to uncover the mechanisms behind injury patterns that have been observed in past research.

METHODS

We analyzed 71 single-vehicle crashes from the Vulnerable Road User Injury Prevention Alliance pedestrian crash database, focusing on crashes involving an SUV or car. Each crash from this database included an in-depth analysis of police reports, bicyclist medical records, crash reconstructions, and injury attribution by a panel of experts.

RESULTS

Bicyclist injuries from crashes with SUVs were more severe than those from crashes with cars, particularly with respect to head injuries. The greater injury severity associated with SUVs was related to these vehicles' tendency to produce injuries from ground contact or from vehicle components near the ground. In contrast, cars were much less likely to produce ground injuries and instead tended to distribute less severe injuries across multiple vehicle components.

CONCLUSIONS

The pattern of results suggest that the size and shape of SUV front ends are responsible for the differences in bicyclist injury outcomes. In particular, we found that SUV crashes inflicted more severe head injuries compared with car crashes and that SUVs were disproportionately likely to throw bicyclists to the ground and run them over.

IIHS small overlap frontal crash test ratings and real-world driver death risk

OBJECTIVE

To evaluate how ratings for the Insurance Institute for Highway Safety (IIHS) driver-side small-overlap frontal crash test predict real-world driver death risk in frontal impacts.

METHODS

IIHS released the driver-side small-overlap frontal crash test in 2012, after manufacturers had improved vehicle designs to make good ratings in the IIHS moderate overlap frontal crash test virtually ubiquitous. In the small overlap test, the vehicle impacts a rigid barrier at 40 mph (64 km/h) with 25% of the vehicle's width overlapping the barrier. As in other IIHS tests, vehicles are rated as good, acceptable, marginal, or poor. Drivers' risk of dying in a frontal crash was estimated by dividing driver deaths by driver involvements in police-reported crashes and modeling with logistic regression to estimate the effect of crash test rating, while controlling for driver age and sex, vehicle type and curb weight, and number of vehicles in the crash.

RESULTS

Drivers of good-rated vehicles were 12% less likely to die in frontal impacts than drivers of poor-rated vehicles. This estimate was 11% for acceptable-rated vehicles and 5% (not statistically significant) for marginal-rated vehicles, compared with vehicles rated poor.

CONCLUSIONS

The current study demonstrates that the IIHS driver-side small-overlap crash test rating encourages vehicle designs that reduce drivers' real-world risk of dying in frontal crashes.

Changes in Traffic Crash Rates After Legalization of Marijuana: Results by Crash Severity

OBJECTIVE

The objective of this study was to estimate the effects of marijuana legalization and the subsequent onset of retail sales on injury and fatal traffic crash rates in the United States during the period 2009-2019.

METHOD

State-by-state quarterly crash rates per mile of travel were modeled as a function of time, unemployment rate, maximum posted speed limit, seat belt use rate, alcohol use rate, percent of miles driven on rural roads, and indicators of legalized recreational marijuana use and sales.

RESULTS

Legalization of the recreational use of marijuana was associated with a 6.5% increase in injury crash rates and a 2.3% increase in fatal crash rates, but the subsequent onset of retail marijuana sales did not elicit additional substantial changes. Thus, the combined effect of legalization and retail sales was a 5.8% increase in injury crash rates and a 4.1% increase in fatal crash rates. Across states, the effects on injury crash rates ranged from a 7% decrease to an 18% increase. The effects on fatal crash rates ranged from a 10% decrease to a 4% increase.

CONCLUSIONS

The estimated increases in injury and fatal crash rates after recreational marijuana legalization are consistent with earlier studies, but the effects varied across states. Because this is an early look at the time trends, researchers and policymakers need to continue monitoring the data.

Changes in Traffic Crash Rates After Legalization of Marijuana: Results by Crash Severity

OBJECTIVE

The objective of this study was to estimate the effects of marijuana legalization and the subsequent onset of retail sales on injury and fatal traffic crash rates in the United States during the period 2009-2019.

METHOD

State-by-state quarterly crash rates per mile of travel were modeled as a function of time, unemployment rate, maximum posted speed limit, seat belt use rate, alcohol use rate, percent of miles driven on rural roads, and indicators of legalized recreational marijuana use and sales.

RESULTS

Legalization of the recreational use of marijuana was associated with a 6.5% increase in injury crash rates and a 2.3% increase in fatal crash rates, but the subsequent onset of retail marijuana sales did not elicit additional substantial changes. Thus, the combined effect of legalization and retail sales was a 5.8% increase in injury crash rates and a 4.1% increase in fatal crash rates. Across states, the effects on injury crash rates ranged from a 7% decrease to an 18% increase. The effects on fatal crash rates ranged from a 10% decrease to a 4% increase.

CONCLUSIONS

The estimated increases in injury and fatal crash rates after recreational marijuana legalization are consistent with earlier studies, but the effects varied across states. Because this is an early look at the time trends, researchers and policymakers need to continue monitoring the data.

Speeding behavior while using adaptive cruise control and lane centering in free flow traffic

OBJECTIVE

Adaptive cruise control (ACC) and lane centering are usually marketed as convenience features but may also serve a safety purpose. However, given that speeding is associated with increased crash risk and worse crash outcomes, the extent to which driver's speed using ACC may reduce the maximum safety benefit they can obtain from this system. The current study was conducted to characterize speeding behavior among drivers using adaptive cruise control and a similar system with added lane centering.

METHODS

We recruited 40 licensed adult drivers from the Boston, Massachusetts, metro area. These drivers were given either a 2017 Volvo S90 or a 2016 Range Rover Evoque to use for about 4 weeks.

RESULTS

Drivers were significantly more likely to speed while they used ACC (95%) relative to periods of manual control (77%). A similar pattern arose for drivers using ACC with added lane centering (96% vs. 77%). Drivers who traveled over the posted limit with these systems engaged also sped slightly faster than drivers controlling their vehicle manually. Finally, we found that these differences were the most pronounced on limited-access roads with a lower speed limit (55 mph).

CONCLUSIONS

These findings point to a possible obstacle to obtaining the full safety potential from this advanced vehicle technology. Any consideration of the net safety effect of ACC and lane centering should account for the effects of more frequent and elevated speeding.

Weekday bicycle traffic and crash rates during the COVID-19 pandemic

INTRODUCTION

One of the most consequential effects of the COVID-19 lockdowns was a dramatic reduction in travel during peak hours. Transportation modes also shifted-in particular, travel by car became more rare while bicycling saw a resurgence. Given that a typical year sees the most severe bicycle crashes in peak commuter traffic, the shift toward bicycle travel that occurred in 2020 will likely have been accompanied by unique changes in rider behavior (e.g., where and when they choose to ride) as well as the frequency and severity of vehicle-bicycle crashes.

METHODS

The current study compared weekday bicycle traffic and crashes in Arlington, VA from March-December 2020 with the same period from years prior, 2013-2019. Bicycle traffic data were obtained from 16 embedded counters placed throughout the study area, in both off-road trails and on-road bike lanes.

RESULTS

We found that 2020 midday traffic nearly doubled compared to the year before, increasing from an average of 68 riders per hour to 120 (+76%). By contrast, morning traffic fell from an average of 87 riders per hour to just 45 (-49%). Change in evening traffic depended on the location of the counters: more evening bicycles were counted on off-road, multi-use trails (+6%) but fewer on on-road lanes (-27%). The changes to 2020 bicycle traffic patterns were also associated with a 28% reduction in bicycle injury crash rate per counted cyclist.

CONCLUSION

The reduced crash risk observed in 2020 was likely due in part to the reduction of morning, on-road bicycle travel, which past research has found to be particularly dangerous for riders. Conversely, the availability of multi-use off-road trails seems to have been a protective factor against bicycle-motor vehicle crash risk in the face of greater bicycle travel volume.

Characteristics of vehicles driven by teens and adults killed in crashes, 2013-2017

INTRODUCTION

Teen drivers experience higher crash risk than their experienced adult counterparts. Legislative and community outreach methods have attempted to reduce this risk; results have been mixed. The increasing presence of vehicle safety features across the fleet has driven fatality numbers down in the past decades, but the disparity between young drivers and others remains.

METHOD

We merged Fatality Analysis Reporting System (FARS) data on fatal crashes with vehicle characteristic data from the Highway Loss Data Institute (HLDI). The analysis compared the vehicle type, size, age, and the presence of select safety features in vehicles driven by teens (ages 15-17 years) and adult drivers (ages 35-50 years) who were killed in crashes from 2013 to 2017. Results were compared with a similar analysis conducted on data from 2007 to 2012.

RESULTS

Teen drivers were more likely than their adult counterparts to be killed while driving older, smaller vehicles that were less likely to have the option to be equipped with side airbags.

DISCUSSION

Teenage drivers remain more likely to be killed while driving older, smaller vehicles than adult drivers. Parents and guardians are mainly responsible for teen vehicle choice, and should keep vehicle size, weight, and safety features in mind when placing their teen in a vehicle. Practical Application: These findings can help guide safer vehicle choice for new teen drivers.

Pedestrian injuries from cars and SUVs: Updated crash outcomes from the vulnerable road user injury prevention alliance (VIPA)

OBJECTIVE

The current short communication was written to update research on real-world pedestrian crashes. In particular, our analysis offers a preliminary update on SUV-pedestrian crash outcomes and how they differ from car-pedestrian crash outcomes. Detailed injury data were linked to vehicle features to offer a better understanding of pedestrian injury etiology.

METHODS

We analyzed 82 single-vehicle crashes from the VIPA pedestrian crash database, focusing on crashes involving an SUV or car. Each crash from this database includes an in-depth analysis of police reports, pedestrian medical records, crash reconstructions, and injury attribution by a panel of experts.

RESULTS

SUVs remain disproportionately likely to injure and kill pedestrians compared with cars, but these differences emerged primarily at crashes of intermediate speed. Crashes at low speeds and high speeds tend to produce similar injury outcomes independent of striking vehicle type (mild and fatal, respectively). The data suggest that the elevated danger to pedestrians from SUVs in these crashes may be largely related to injuries caused by impacts with the vehicles' leading edge: the bumper, grille, and headlights.

CONCLUSIONS

Although the current analysis was based on a non-nationally representative dataset, the elevated pedestrian injury risk originating from SUVs' leading edge is consistent with past research on the subject. That is, despite the changes in vehicle design and fleet composition over the past two decades, SUVs may remain disproportionately likely to injure pedestrians compared with cars.

Trends in aggressivity and driver risk for cars, SUVs, and pickups: Vehicle incompatibility from 1989 to 2016

Objective: When 2 vehicles of different sizes collide, the occupants of the smaller vehicle are more likely to be injured than the occupants of the larger vehicle. The larger vehicle is both more protective of its own occupants and more aggressive toward occupants of the other vehicle. However, larger, heavier vehicles tend to be designed in ways that amplify their incompatibility with smaller, lighter vehicles (by having a higher ride height, for example). A 2012 study by the Insurance Institute for Highway Safety (IIHS) concluded that fatalities caused by design incompatibility have decreased in recent years. The current study was conducted to update the 2012 IIHS analysis and to explore trends in vehicle incompatibility over time. Methods: Analyses examined deaths in crashes involving 1- to 4-year-old passenger vehicles from 1989 to 2016 collected from the Fatality Analysis Reporting System (FARS). Trends in driver risk were examined by comparing driver death rates per million registered vehicle years across vehicle type and size. Trends in aggressivity were examined by comparing partner driver death rates across vehicle type and size. Results: Cars and SUVs have continued their trend toward reduced incompatibility. In 1989-1992, SUVs were 132% more likely to kill the driver in a partner car compared with when a car crashed with another car. By 2013-2016, this value had dropped to 28%. Pickups and cars remain just as incompatible in 2013-2016 as they were in 1989-1992, however (159% vs. 158%). Remaining pickup incompatibility may be largely due to excess curb weight rather than to shape or design features, because light pickups were just 23% more likely to kill the driver in a partner car compared with when a car crashed with another car. Conclusions: The trend toward reduced fleet incompatibility has continued in the latest crash data, particularly for cars and SUVs. Although pickup-car incompatibility has also decreased over time, pickups remain disproportionately aggressive toward other vehicles, possibly due to their greater average curb weight. Reducing the weight of some of the heaviest vehicles and making crash avoidance technology fitment more widespread may be promising means to reduce remaining fleet incompatibility. Identifying the source of remaining incompatibility will be important for safety improvements going forward.

Personality strengths in romantic relationships: Measuring perceptions of benefits and costs and their impact on personal and relational well-being

Three studies using samples of people in romantic relationships were conducted to create a new individual difference measure of partner strengths in couples. The 2 perceptions of partner strengths included (1) appreciation of their use and effectiveness and (2) recognition of costs associated with their use. Factor analyses supported 2-factors and we found that greater appreciation of partner strengths predicted greater relationship satisfaction, commitment, investment, intimacy, self-expansion, and support for goal pursuit; recognizing significant costs with partner strengths was inversely related to several outcomes. Using a 1-week daily diary, we found that appreciation of partner strength use and recognition of costs associated with these strengths predicted daily relationship satisfaction and whether basic psychological needs were met within the relationship. The explanatory power of partner strength perceptions could not be explained by the actual character strengths or Big Five personality traits of partners, support for positive self-disclosures (capitalization), or gratitude for relationship partners. Finally, we found that the relational consequences of partner strength perceptions were not just "in the head" of the perceiver-influencing partner relational outcomes. This research program provides evidence for the use of a new measure of how strengths are perceived to better understand romantic couples and aspirational targets in clinical interventions. (PsycINFO Database Record

A Little Anthropomorphism Goes a Long Way

OBJECTIVE

We investigated the effects of exogenous oxytocin on trust, compliance, and team decision making with agents varying in anthropomorphism (computer, avatar, human) and reliability (100%, 50%).

BACKGROUND

Authors of recent work have explored psychological similarities in how people trust humanlike automation compared with how they trust other humans. Exogenous administration of oxytocin, a neuropeptide associated with trust among humans, offers a unique opportunity to probe the anthropomorphism continuum of automation to infer when agents are trusted like another human or merely a machine.

METHOD

Eighty-four healthy male participants collaborated with automated agents varying in anthropomorphism that provided recommendations in a pattern recognition task.

RESULTS

Under placebo, participants exhibited less trust and compliance with automated aids as the anthropomorphism of those aids increased. Under oxytocin, participants interacted with aids on the extremes of the anthropomorphism continuum similarly to placebos but increased their trust, compliance, and performance with the avatar, an agent on the midpoint of the anthropomorphism continuum.

CONCLUSION

This study provides the first evidence that administration of exogenous oxytocin affected trust, compliance, and team decision making with automated agents. These effects provide support for the premise that oxytocin increases affinity for social stimuli in automated aids.

APPLICATION

Designing automation to mimic basic human characteristics is sufficient to elicit behavioral trust outcomes that are driven by neurological processes typically observed in human-human interactions. Designers of automated systems should consider the task, the individual, and the level of anthropomorphism to achieve the desired outcome.

Placebo effects in cognitive training

Although a large body of research shows that general cognitive ability is heritable and stable in young adults, there is recent evidence that fluid intelligence can be heightened with cognitive training. Many researchers, however, have questioned the methodology of the cognitive-training studies reporting improvements in fluid intelligence: specifically, the role of placebo effects. We designed a procedure to intentionally induce a placebo effect via overt recruitment in an effort to evaluate the role of placebo effects in fluid intelligence gains from cognitive training. Individuals who self-selected into the placebo group by responding to a suggestive flyer showed improvements after a single, 1-h session of cognitive training that equates to a 5- to 10-point increase on a standard IQ test. Controls responding to a nonsuggestive flyer showed no improvement. These findings provide an alternative explanation for effects observed in the cognitive-training literature and the brain-training industry, revealing the need to account for confounds in future research.

A longitudinal examination of re-employment quality on internalizing symptoms and job-search intentions

Underemployed workers-those receiving less pay, working fewer hours, or using fewer skills than they would prefer-appear to experience negative mental health outcomes similar to the unemployed. Prior cross-sectional research provides mixed empirical evidence for this conclusion, however. The current study sought to clarify the impact of underemployment longitudinally, assessing mental health 5 times over 8 months after job loss. In addition to the commonly used indicators of underemployment, we designed a measure of cognitive complexity using the Occupational Information Network (O*NET), an extensive government database used to organize and categorize occupational information. Replicating past research, we found concurrent associations between all indexes of reemployment job quality and internalizing symptoms in the period immediately after reemployment. However, when controlling for quality of prior employment, all indicators except our measure for cognitive complexity became nonsignificant. As participants transitioned from unemployment to reemployment, only reductions in cognitive complexity were associated with sustained general internalizing symptoms. We also found that although changes in cognitive complexity had an immediate impact on the well-being of the recently reemployed, only the number of available weekly hours (full-time vs. part-time status) was relevant 6 to 12 weeks later. Our longitudinal model thus provides significant nuance to the current understanding of underemployment and mental health.

A contextual approach to experiential avoidance and social anxiety: evidence from an experimental interaction and daily interactions of people with social anxiety disorder

Experiential avoidance (EA), the tendency to avoid internal, unwanted thoughts and feelings, is hypothesized to be a risk factor for social anxiety. Existing studies of experiential avoidance rely on trait measures with minimal contextual consideration. In two studies, we examined the association between experiential avoidance and anxiety within real-world social interactions. In the first study, we examined the effect of experiential avoidance on social anxiety in everyday life. For 2 weeks, 37 participants with Social Anxiety Disorder (SAD) and 38 healthy controls provided reports of experiential avoidance and social anxiety symptoms during face-to-face social interactions. Results showed that momentary experiential avoidance was positively related to anxiety symptoms during social interactions and this effect was stronger among people with SAD. People low in EA showed greater sensitivity to the level of situational threat than high EA people. In the second study, we facilitated an initial encounter between strangers. Unlike Study 1, we experimentally created a social situation where there was either an opportunity for intimacy (self-disclosure conversation) or no such opportunity (small-talk conversation). Results showed that greater experiential avoidance during the self-disclosure conversation temporally preceded increases in social anxiety for the remainder of the interaction; no such effect was found in the small-talk conversation. Our findings provide insight into the association between experiential avoidance on social anxiety in laboratory and naturalistic settings, and demonstrate that the effect of EA depends upon level of social threat and opportunity.

Perceived responsiveness during an initial social interaction with a stranger predicts a positive memory bias one week later

Prior research has found that perceiving positive responses from others following self-disclosures enhances social bonds and plays a role in the maintenance of romantic relationships. We sought to extend this effect by exploring perceived responsiveness to good news in the context of initial social interactions with a stranger. In this study, unacquainted college students (n = 106) participated in a 45-minute semi-structured social interaction, and information on their emotions and behaviours was collected immediately after and one week later. We found that the receipt of supportive reactions to self-disclosure attempts during the social interaction was associated with immediate positivity and a more positive memory of the event (remembered enjoyment and positive emotions) one week later. This effect could not be attributed to how positively the event was experienced immediately afterwards, suggesting that perceived responsiveness during an initial social interaction facilitates a positive memory bias. These results offer new insights into how friendships might develop and be maintained.