Life-threatening motor vehicle crashes in bright sunlight

Reduction of Glare Discomfort and Photostress Recovery Time Through the Use of a High-Energy Visible-Filtering Contact Lens

OBJECTIVES

Glare discomfort (GDC) is the slight pain (discomfort) that arises when exposed to light that exceeds one's adaptive state. Such light can also cause a temporary loss in visual function (photostress, PS). We tested the hypothesis that filtering with a high-energy visible (HEV) light-filtering contact lens can reduce GDC and speed PS recovery time.

METHODS

Sixty-one subjects were randomized and fit with study lenses and 58 subjects completed as cohort (20-65 years of age). A double-masked, randomized, contralateral design was used (HEV filter on one eye; control lens on the other). Participants were given a 5-s exposure to a broadband white photostressor. Video images were analyzed, and palpebral fissure size during exposure was measured, as was PS recovery time to a 2-degree mid-wave target.

RESULTS

The HEV-filtering test lens was statistically superior ( P <0.0001) to the clear comparison contact lens with respect to the magnitude of squint (44.9% squint reduction) and photostress recovery time (24.3% faster recovery).

CONCLUSIONS

High-energy visible light-filtering contacts can reduce GDC and speed PS recovery. Filtering HEV light before it is incident upon the retina is a natural strategy (e.g., by the lens and macular pigment) for attenuating some of the deleterious effects of bright broadband light.

Population-based case-control study of the effect of sun glare on pedestrian fatalities in Taiwan

OBJECTIVES

Sun glare is a serious driving hazard and increases crash risks. Relatively few studies have examined the effects of sun glare on pedestrian fatalities, given that a crash has occurred. The primary objective of this study was to investigate the effect of sun glare on pedestrian fatalities.

DESIGN

A population-based case-control study.

SETTING

Taiwan.

PARTICIPANTS

Using the Taiwan National Traffic Crash Data and sunrise and sunset data from the National Oceanic and Atmospheric Administration for the period 2003 to 2016, 100 411 pedestrians involved in crashes were identified. Of these crashes, 13 355 and 87 056 were glare-related (case) and non-glare-related (control) crashes, respectively.

METHODS

To account for unobserved heterogeneity, mixed logit models were estimated to identify the determinants of pedestrian fatalities.

MAIN OUTCOME MEASURES

Pedestrian fatalities.

RESULTS

Pedestrians involved in glare-related crashes were more likely to be fatally injured than those in non-glare-related crashes (β=0.527; t=3.21). Other contributory factors to fatal injuries among pedestrians were older pedestrians (β=0.553; t=2.33), male drivers (β=0.324; t=2.33), older drivers (β=0.218; t=2.14), intoxicated motorists (β=0.606; t=2.85), rural roadways (β=0.985; t=3.92), overtaking manoeuvres (β=0.472; t=3.58), heavy vehicle crash partners (β=0.248; t=2.78) and sunset hours (β=0.274; t=3.08). Walking against traffic appeared beneficial for decreasing injury severity (β=-0.304; t=-2.76).

CONCLUSIONS

Sun glare is associated with pedestrian fatalities. Older pedestrians, male drivers, older drivers and intoxicated motorists are prevalent determinants of pedestrian fatalities in glare-related crashes.

Life-threatening alcohol-related traffic crashes in adverse weather: a double-matched case-control analysis from Canada

IMPORTANCE

Drunk driving is a major cause of death in North America, yet physicians rarely counsel patients on the risks of drinking and driving.

OBJECTIVE

To test whether the risks of a life-threatening alcohol-related traffic crash were further accentuated by adverse weather.

DESIGN

Double matched case-control analysis of hospitalised patients.

SETTING

Canada's largest trauma centre between 1 January 1995 and 1 January 2015.

PARTICIPANTS

Patients hospitalised due to a life-threatening alcohol-related traffic crash.

EXPOSURE

Relative risk of a crash associated with adverse weather estimated by evaluating the weather at the place and time of the crash (cases) compared with the weather at the same place and time a week earlier and a week later (controls).

RESULTS

A total of 2088 patients were included, of whom the majority were drivers injured at night. Adverse weather prevailed among 312 alcohol-related crashes and was significantly more frequent compared with control circumstances. The relative risk of a life-threatening alcohol-related traffic crash was 19% higher during adverse weather compared with normal weather (95% CI: 5 to 35, p=0.006). The absolute increase in risk amounted to 43 additional crashes, extended to diverse groups of patients, applied during night-time and daytime, contributed to about 793 additional patient-days in hospital and was distinct from the risks for drivers who were negative for alcohol.

CONCLUSIONS

Adverse weather was associated with an increased risk of a life-threatening alcohol-related traffic crash. An awareness of this risk might inform warnings to patients about traffic safety and counselling alternatives to drinking and driving.

Full moon and traffic accident-related emergency ambulance transport: A nationwide case-crossover study

BACKGROUND

Several studies have examined the association between environmental factors and traffic accidents. However, the role of a full moon in triggering emergency ambulance transport due to road traffic casualties is unclear. Thus, we aimed to examine whether a full moon contributes to the incidence of emergency transport due to road traffic crashes.

METHODS

We acquired nationwide data on daily emergency transport due to road traffic crashes from all 47 prefectures of Japan from 2010 to 2014. We conducted a time-stratified case-crossover study using conditional Poisson regression to examine the relationship between the occurrence of a full moon and emergency transport due to road traffic crashes for each prefecture. Prefecture-level results were combined using a random-effects meta-analysis to evaluate nation-level estimates.

RESULTS

There were 842,554 cases of emergency transport due to road traffic crashes across 1826 nights (62 full moon nights: n = 29,584; 1764 control nights: n = 812,970). On days with a full moon, the pooled adjusted relative risk (RR) of emergency transport due to traffic accidents was 1.042 (95% confidence interval [CI], 1.021-1.063). Overall, 4.03% (95% CI: 2.06-5.93) of the cases (1192 cases) were attributable to full moon nights. Stratified analyses revealed a significant increase in emergency transport due to traffic accidents on full moon nights for males, people aged ≥40 years, and before midnight.

CONCLUSIONS

Full moon nights are associated with an increase in the incidence of emergency transport due to road traffic crashes. These results indicate that public health strategies should account for full moon nights to decrease emergency transport due to traffic accidents.

Optical illusions and life-threatening traffic crashes: A perspective on aerial perspective

Aerial perspective illusion is a feature of visual perception where landscapes appear relatively close in clear light and distant in dim light. We hypothesized that bright sunlight might cause drivers to perceive distant terrain as relatively close and misinterpret the approach speed of surrounding landscape as unduly slow. This hypothesis would mean, in turn, that drivers in bright sunlight may underestimate their progress on the road, compensate by traveling at a faster baseline speed, and ultimately increase the prevailing risk of a life-threatening traffic crash. We conducted three pilot studies to illustrate how the illusion might contribute to a life- threatening traffic crash. The first illustration used a questionnaire to demonstrate that most respondents were mistaken when judging the distance between simple balls in different positions. The second illustration involved an experimental manipulation to assess whether aerial perspective influenced judgments about the relative positions of vehicles in traffic. The third illustration analyzed a segment of high-volume fast-speed traffic and found an increased frequency of speeding under bright sunlight. Together with past work based on the visual arts, these examples illustrate how an aerial perspective illusion can affect distance perception, may appear in realistic traffic situations, and could potentially contribute to the risk of a life-threatening traffic crash. An awareness of this hypothesis might lead to applications on how optical illusions could extend to everyday traffic and might potentially inform safety warnings to prevent life- threatening crashes.

The full moon and motorcycle related mortality: population based double control study

OBJECTIVE

To test whether a full moon contributes to motorcycle related deaths.

DESIGN

Population based, individual level, double control, cross sectional analysis.

SETTING

Nighttime (4 pm to 8 am), United States.

PARTICIPANTS

13 029 motorcycle fatalities throughout the United States, 1975 to 2014 (40 years).

MAIN OUTCOME MEASURE

Motorcycle fatalities during a full moon.

RESULTS

13 029 motorcyclists were in fatal crashes during 1482 relevant nights. The typical motorcyclist was a middle aged man (mean age 32 years) riding a street motorcycle with a large engine in a rural location who experienced a head-on frontal impact and was not wearing a helmet. 4494 fatal crashes occurred on the 494 nights with a full moon (9.10/night) and 8535 on the 988 control nights without a full moon (8.64/night). Comparisons yielded a relative risk of 1.05 associated with the full moon (95% confidence interval 1.02 to 1.09, P=0.005), a conditional odds ratio of 1.26 (95% confidence interval 1.17 to 1.37, P<0.001), and an absolute increase of 226 additional deaths over the study interval. The increase extended to diverse types of motorcyclists, vehicles, and crashes; was accentuated during a supermoon; and replicated in analyses from the United Kingdom, Canada, and Australia.

CONCLUSION

The full moon is associated with an increased risk of fatal motorcycle crashes, although potential confounders cannot be excluded. An awareness of the risk might encourage motorcyclists to ride with extra care during a full moon and, more generally, to appreciate the power of seemingly minor distractions at all times.