Task-Relevant Smartphone Messages Within Work Zones: A Driving Simulation Study.

OBJECTIVE: This study explored the impact of in-vehicle messages relative to roadside messages to alert drivers to events within a simulated work zone, in order to determine if these messages can improve driving performance within the work zone. BACKGROUND: Safety risks in work zones are usually mitigated by design standards and clear signage to communicate work zone information to drivers. Due to distraction and other driving task demands, these signs are not always noticed by motorists, nor are they always followed when they are noticed. METHOD: The driving simulation tested drivers in two different types of work zones, shoulder work, and lane closure. Participants drove through these work zones three times, each with different messaging interfaces to communicate hazardous events to the driver. The interfaces included a roadside, portable changeable message sign, a smartphone presenting only auditory messages, and a smartphone presenting audio-visual messages. RESULTS: There was significantly better driving performance on key metrics including lane deviation for the in-vehicle message conditions relative to the roadside signs. Furthermore, drivers directed visual attention toward the roadway for the in-vehicle message conditions relative to the roadside sign condition. CONCLUSION: The results indicate that in-vehicle messaging could provide benefits to primary task performance in driving if the message content is appropriately designed. APPLICATION: The findings provide support for a design framework to support in-vehicle communication to drivers approaching work zones and other environments to safely alert them to hazards.

Evaluation of the efficacy of an intersection conflict warning system at two-way stop-controlled rural intersections: difference-in-differences and triple-difference analytical approaches.

OBJECTIVE: Intersection conflict warning systems (ICWSs) have been implemented at high-risk two-way stop-controlled intersections to prevent right-angle crashes and associated injuries. This study involved investigation of the impacts of ICWSs on crash reductions. METHODS: The study used a quasi-experimental design to analyse the potential causal relations between Minnesota's ICWSs and various crash rate outcomes (including total, injury, non-injury, targeted right-angle and non-right-angle crashes) in pre-post analyses. A restricted randomisation method enabled identification of three controls to each ICWS treatment intersection, and included as many comparable intersection characteristics as possible. Annual crash rates (per year per intersection) were analysed over the same periods before and after system activation for treatment and control intersections in each matched group. Pre-crash data for 3 years and post-crash data for up to 5 years were included, ranging from 2010 to 2018. Negative binomial regression models with generalised estimating equations were applied to estimate the average, immediate and continuing treatment effects of ICWSs, through the difference-in-differences and difference-in-difference-in-difference approaches, respectively. RESULTS: The ICWS treatment was significantly associated with a decreasing trend for targeted right-angle crash rates posttreatment. Although not statistically significant, most crash rate outcomes appeared to be elevated immediately after treatment (statistically significant for sideswipe crashes only). Pre-post differences in average crash rates (over entire periods), except for incapacitating injury-related crashes, were not statistically significant between treatment and control intersections. CONCLUSIONS: The study provided important insight into potential causal associations between intersection safety countermeasures and crashes at high-risk rural two-way stop-controlled intersections.

Superior side sound localisation performance in a full-chassis driving simulator.

Alerts presented through the auditory modality improve drivers' crash avoidance performance in driving simulations, but drivers' ability to accurately localise the source of the auditory alerts is understudied. Because the results of driving simulation studies may hinge on assumptions that sound locations are accurately perceived by drivers, this study used a sound localisation task in a full-chassis driving simulator. Twenty-nine participants engaged in a sound localisation task while seated in the driving simulator. Performance was assessed by sound localisation accuracy, relative directional error, and participant confidence across seven sound sources surrounding the simulator. Performance was best when sounds were presented in left and right cardinal regions, and poorest when presented from the front and rear. Participants were less confident in their localisation judgments when sounds were presented from the rear. Practitioner summary: Drivers' ability to accurately localise auditory alerts is understudied. Participants performed an auditory localisation task with external sounds while seated in a full-chassis driving simulator. Participants were better detecting sounds from the sides instead of the front and rear. This has implications for external auditory alarms during driving. Abbreviations: ANOVA: analysis of variance; dB: decibel; f: frequency; Hz: hertz; LHD: left hand drive; ms: milliseconds; RTI: realtime technologies; s: seconds; SPL: sound pressure level.

Evaluation of driver navigational errors and acceptance of a simulated J-turn intersection.

The J-turn intersection is a novel roadway design which decreases the points of conflict at an intersection, by restricting straight crossing and left-turning movements from the minor road across the highway. The novelty of the intersection design may lead to driver errors and dissatisfaction. This study provides an examination of how naïve or first-time drivers may initially navigate J-turns during their first and early exposures to the novel intersection design. Thirty-six participants with limited previous experience and knowledge of J-turns participated in a simulation study to examine their acceptance of J-turns and left turning navigational performance at three simulated J-turn intersections in counterbalanced order, each featuring one of three signage levels. Results revealed participants committed slightly more frequent minor errors (e.g., inefficient lane selection) and significantly more major errors (e.g., missed U-turn) during the first J-turn exposure and these errors tended to decline during subsequent exposures, while moderate severity errors (e.g., risky lane change) slightly increased. Participants' J-turn acceptance significantly declined following simulated driving exposure. The decline in J-turn acceptance was found to be greater among participants who experienced major severity errors; however, more frequent minor errors were associated with increased acceptance. Signage level had little effect on errors, but participants preferred improved signage or on-road markings to guide crossing movements. This work suggests that advanced educational programs and community initiatives should be utilized to prepare drivers for how to navigate J-turns rather than only rely on J-turn exposure to improve driver performance and acceptance.

Exploring Combat Tourniquet Application Errors and Duration Among Skilled and Novice Medical Trainees.

INTRODUCTION: The use of tourniquets in combat medicine continues to be a key focus as they have consistently been shown to combat one of the leading causes of preventable death on the battlefield, massive hemorrhage to extremities. The present study analyzed tourniquet application among combat medics (68W) and combat lifesavers (CLSs) in a training environment to determine whether trainees' performance is consistent among one another and whether performance can be associated with participant demographics such as experience or role. MATERIALS AND METHODS: Study participants treated male and female patient simulators within a tactical field care phase, both of which experienced an amputated leg and required the application of a Combat Application Tourniquet (CAT). To assess tourniquet application variability and performance, a series of application subtasks and potential errors were measured via video coding of the scenarios by a team of 5 coders. Time to tourniquet application and tourniquet application duration were also coded to assess correlations between application duration and variability or performance. RESULTS: Results from analyzing tourniquet application subtasks and errors through a series of one-way ANOVA tests showed that application of the CAT first, hasty CAT application, and high tourniquet application were not predictive of participant role, time within the role, and self-reported tourniquet skill, confidence, or experience. Such demographic variables were also not predictive of successful tourniquet application as defined by the number of windlass rod rotations. Results from binomial logistic regressions showed that participant role and self-reported tourniquet skill and experience were predictors of tourniquet application duration. CONCLUSION: The findings suggest that high variability in CAT application methodology and performance exists among CLS and combat medics, which is largely not predictable by various demographics such as role, experience within the designated role, and self-reported confidence, skill, or experience. The observed disconnect between training or experience and CAT application performance suggests substantial variability in the consistency of training for both CLS and 68W soldiers. These inconsistencies may stem from variability in instructor knowledge, teaching styles, or training materials or may be developed through informal methods such as experiences in the field or recommendations from colleagues and experts. These findings highlight a potential need to reassess CAT application training, particularly in regard to consistency and validation. Finally, it should be noted that the study's findings may be limited or fail to capture some study effects because of the sample size and wide range of reported experience among participants.

Farm vehicle crashes on public roads: Analysis of farm-level factors.

PURPOSE: Rural public roads experience higher crash fatality rates than other roadways, with agricultural equipment adding greater risk of injury and fatality. This study set out to describe farmers' experiences with farm equipment crashes and predictors of crashes at the farm level. METHODS: A survey of farm operators was conducted in 9 Midwestern states (IL, IA, KS, MN, MO, NE, ND, SD, and WI) in collaboration with the US Department of Agriculture's National Agricultural Statistical Service. FINDINGS: From 1,282 farms operating equipment on public roads in 2013, 7.6% of farmers reported that equipment from their farm had ever been in a crash (n = 97). Crashes occurred most often in June-August (44.0%) and were most often reported as being during the daytime (71.3%), on dry roads (79.4%), or in clear weather (71.4%). While most farmers responded that they were driving the farm equipment at the time of the crash (52.0%), nearly half of crashes involved their employees as the driver (48.0%). Crashes often went unreported to law enforcement (28.6%). CONCLUSION: To illustrate crash probabilities for farms with different profiles, we included farm acreage, crop farming, vehicle horsepower, annual miles driven, and the total number of farm vehicles driven on public roads in a predictive model. Large crop farms of 241+ acres, those who drove farm vehicles 1,430+ miles per year, and those with 20 or more farm vehicles had the highest probability of crash of 0.14.

A Pilot Study on the Role of Experience and Patient Gender on MARCH Treatment Sequence.

INTRODUCTION: The brevity of training for soldiers and combat medics to learn how to provide treatment on the battlefield may restrict optimal performance for treating chest and airway injuries, particularly when treating female soldiers. The present study tested treatment performance on patient simulators by battlefield medic trainees to determine whether there is a need for more extensive training on chest and airway procedures on female soldiers. MATERIALS AND METHODS: Battlefield medic trainees treated male and female patient simulators in counterbalanced order. The assessment considered the effects of patient gender and order on procedures performed, particularly critical chest and airway interventions such as needle chest decompression (NCD), and considered the appropriate order of treatment tasks. Four coders rated video footage of three simulated procedures, i.e., tourniquet, chest seal (front and back application), and NCD, using a binary coding system to determine completeness and order correctness according to the Massive hemorrhage, Airway, Respiration, Circulation, and Head injury/Hypothermia (MARCH) mnemonic. RESULTS: Results from analysis of variance showed that when presented with a female patient first, trainees performed significantly fewer total procedures on both the female and male simulators. More experienced trainees completed significantly more procedures compared to trainees with minimal experience. Results from the binary logistic regression showed that trainees with more experience and trainees presented with the male patient simulator first performed significantly more procedures in the correct order. Finally, an examination of the NCD procedure found that trainees presented with the female patient simulator first had more errors and that trainees with less experience were less likely to perform the procedure adequately. CONCLUSIONS: The findings suggest that treating a female patient first may lead to undertreatment of both patients. Furthermore, the observed differences in treating sensitive areas of the body (e.g., near female breasts) suggest providing greater opportunities for trainees to practice often missed or incorrectly performed procedures. Treating a female patient remains a novel experience for many trainees, such that trainees are less likely to fully treat a female patient and are less likely to treat female soldiers for the most life-threatening injuries. In fact, the initial presentation of the female patient simulator appeared to affect experienced trainees, suggesting that removing the experience of novelty and stress requires more extensive exposure and alternative training. The study's small sample size with a wide range of trainee experience may limit the findings, which may fail to capture some study effects. Finally, the study did not request trainees' experience treating female soldiers, so future studies should examine the extent to which experience is predictive of performance. There is a need for more interactive approaches in patient simulations to provide opportunities for practice, especially those that require the treatment of sensitive areas.

Characteristics and Risk Factors for Electric Scooter-Related Crashes and Injury Crashes among Scooter Riders: A Two-Phase Survey Study.

Electric scooters (or e-scooters) are among the most popular micromobility options that have experienced an enormous expansion in urban transportation systems across the world in recent years. Along with the increased usage of e-scooters, the increasing number of e-scooter-related injuries has also become an emerging global public health concern. However, little is known regarding the risk factors for e-scooter-related crashes and injury crashes. This study consisted of a two-phase survey questionnaire administered to a cohort of e-scooter riders (n = 210), which obtained exposure information on riders' demographics, riding behaviors (including infrastructure selection), helmet use, and other crash-related factors. The risk ratios of riders' self-reported involvement in an e-scooter-related crash (i.e., any crash versus no crash) and injury crash (i.e., injury crash versus non-injury crash) were estimated across exposure subcategories using the Negative Binomial regression approach. Males and frequent users of e-scooters were associated with an increased risk of e-scooter-related crashes of any type. For the e-scooter-related injury crashes, more frequently riding on bike lanes (i.e., greater than 25% of the time), either protected or unprotected, was identified as a protective factor. E-scooter-related injury crashes were more likely to occur among females, who reported riding on sidewalks and non-paved surfaces more frequently. The study may help inform public policy regarding e-scooter legislation and prioritize efforts to establish suitable road infrastructure for improved e-scooter riding safety.

Design and evaluation of a rural intersection conflict warning system and alternative designs among various driver age groups.

Advanced Rural Intersection Conflict Warning Systems (RICWS) were deployed as countermeasures to reduce severe right-angle crashes at rural thru-STOP controlled intersections across the United States (U.S.). The simulator study designed and evaluated alternative RICWS designs to existing RICWS interventions, in varying rural driving scenarios, across age groups (N = 40 novice teenage, 40 middle-aged, and 40 older drivers). Each participant was randomly assigned to a RICWS design, either the original or an alternative, and drove through sequences of 17 thru-STOP controlled rural intersections (nine RICWS intervention and eight control intersections). Drivers' gap acceptance performance, intersection driving performance, traffic violation behaviors and self-reported workload were evaluated between intervention and control intersections. Regression models, applying the Generalized Estimating Equation (GEE), enabled efficacy determination of each RICWS design and an aggregated RICWS intervention effect, averaged across all simulated RICWS designs, among different levels of moderating factors. The safety performance and possible risks associated with the use of different RICWS designs were identified. Specifically, the original RICWS design had a significantly greater risk of STOP-sign violations at clear-view intersections with low traffic volumes, compared with control intersections (Risk Ratio = 2.18, 95% CI = 1.03 to 4.64). Except for Alternative RICWS Design 1, the alternative RICWS designs did not appear to outperform the Original RICWS Design. The moderating effects of drivers' ages and intersection types on aggregated RICWS intervention effects were also examined. This study provides important safety implications for development and evaluation of intelligent intersection warning systems, targeted to vulnerable driver populations at high-risk rural intersections.

Are cellular phone blocking applications effective for novice teen drivers?

PROBLEM: Distracted driving is a significant concern for novice teen drivers. Although cellular phone bans are applied in many jurisdictions to restrict cellular phone use, teen drivers often report making calls and texts while driving. METHOD: The Minnesota Teen Driver Study incorporated cellular phone blocking functions via a software application for 182 novice teen drivers in two treatment conditions. The first condition included 92 teens who ran a driver support application on a smartphone that also blocked phone usage. The second condition included 90 teens who ran the same application with phone blocking but which also reported back to parents about monitored risky behaviors (e.g., speeding). A third control group consisting of 92 novice teen drivers had the application and phone-based software installed on the phones to record cellular phone (but not block it) use while driving. RESULTS: The two treatment groups made significantly fewer calls and texts per mile driven compared to the control group. The control group data also demonstrated a higher propensity to text while driving rather than making calls. DISCUSSION: Software that blocks cellular phone use (except 911) while driving can be effective at mitigating calling and texting for novice teen drivers. However, subjective data indicates that some teens were motivated to find ways around the software, as well as to use another teen's phone while driving when they were unable to use theirs. PRACTICAL APPLICATIONS: Cellular phone bans for calling and texting are the first step to changing behaviors associated with texting and driving, particularly among novice teen drivers. Blocking software has the additional potential to reduce impulsive calling and texting while driving among novice teen drivers who might logically know the risks, but for whom it is difficult to ignore calling or texting while driving.

Effects of simulated cataracts on speech intelligibility.

Limited research is available on how well visual cues integrate with auditory cues to improve speech intelligibility in persons with visual impairments, such as cataracts. We investigated whether simulated cataracts interfered with participants' ability to use visual cues to help disambiguate a spoken message in the presence of spoken background noise. We tested 21 young adults with normal visual acuity and hearing sensitivity. Speech intelligibility was tested under three conditions: auditory only with no visual input, auditory-visual with normal viewing, and auditory-visual with simulated cataracts. Central Institute for the Deaf (CID) Everyday Speech Sentences were spoken by a live talker, mimicking a pre-recorded audio track, in the presence of pre-recorded four-person background babble at a signal-to-noise ratio (SNR) of -13 dB. The talker was masked to the experimental conditions to control for experimenter bias. Relative to the normal vision condition, speech intelligibility was significantly poorer, [t(20)=4.17, p<.01, Cohen's d=1.0], in the simulated cataract condition. These results suggest that cataracts can interfere with speech perception, which may occur through a reduction in visual cues, less effective integration or a combination of the two effects. These novel findings contribute to our understanding of the association between two common sensory problems in adults: reduced contrast sensitivity associated with cataracts and reduced face-to-face communication in noise.