Low conspicuity of motorcycles for car drivers: dominant role of bottom-up control of visual attention or deficit of top-down control?

Nationwide Analysis of Motorcycle-Associated Injuries and Fatalities in the United States: Insufficient Prevention Policies or Abandoned Laws?

BACKGROUND

Motorcycle road traffic collisions are a major cause of mortality in the United States. We aimed to analyze the temporal and statewide trends in motorcycle collision fatalities (MCFs) nationwide and their association with state laws regarding motorcycle helmet requirements, lane splitting, speeding, intoxicating driving, and red light cameras.

METHODS

A retrospective review of United States MCF/capita from 2015 to 2019 was performed using the Fatality Analysis Reporting System database. MCF/capita was defined as a motorcyclist death per 100 000 motorcyclist registrations. Independent-samples t-test and ANOVA were used to determine differences, with significance defined as P < .05. Linear regression analysis and Pearson's correlation were used to further determine associations between variables.

RESULTS

The majority of fatalities occurred in males (n = 21 354, 91.0%), ages 25-54 (n = 13 728, 58.5%), and Caucasians (n = 19 195, 81.8%). A total of 24 states and DC exhibited positive trends in MCF/capita from 2015 to 2019. There was no significant difference in MCF/capita between states who had mandatory helmet laws for all, partial requirements, and states with no law (63.4 vs 54.3 vs 33.6, P = .360). Among fatalities involving alcohol, a significantly greater number of MCF/capita were found above the legal limit of .08 compared to the group with a blood alcohol concentration of .01-.07 (17.8 vs 4.5, P < .001).

CONCLUSION

Motorcyclist fatalities continue to pose a public health risk, with 24 states showing an upward trend. Additional interventions and laws are needed to decrease the number of motorcyclist deaths. Further strategy on implementation and enforcement of helmet laws and alcohol consumption may be an essential component.

Motorcycle Conspicuity Issues and Intervention: A Systematic Review

Background

Conspicuity has been one of the key factors in motorcycle road crashes around the world. The inability and difficulty of other road users in detecting motorcycles either at day or at night have contributed to conspicuity related motorcycle crashes. This literature review attempts to understand the motorcycle conspicuity issues in road traffic. The review also analyses relevant types of conspicuity intervention in terms of its effectiveness in enhancing motorcycle conspicuity that had been discussed in past studies.

Methods

Using specific keywords and search terms, relevant articles were screened, identified and analyzed systematically using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results

Twenty-seven final articles were reviewed and found that almost every part of motorcycle and motorcyclist's conspicuity intervention have been covered in past studies. In terms of conspicuity aids, the majority of past studies discussed conspicuity enhancement in the frontal area, particularly on motorcycle daytime running headlight (DRH) color and configurations. Few other studies have discussed in other areas, particularly on rear running and brake light and motorcycle color. There were also numerous studies looking at motorcyclists' appearances in terms of their attire and helmet color.

Conclusion

Motorcycle and motorcyclist's appearances are highly associated with the risk of motorcycle crashes. The most important part of enhancing motorcycle conspicuity is to ensure motorcycle appearance is always in contrast with the road traffic environment.

Mechanisms underlying cognitive conspicuity in the detection of cyclists by car drivers

OBJECTIVE

The aim of this study was to evaluate the visibility of cyclists for motorists in a simulated car driving task.

BACKGROUND

In several cases involving collisions between cars and cyclists, car drivers failed to detect the latter in time to avoid collision because of their low conspicuity.

METHOD

2 groups of motorists (29.2 years old), including 12 cyclist-motorists and 13 non-cyclist-motorists, performed a vulnerable road user detection task in a car-driving simulator. They had to detect cyclists and pedestrians in an urban setting and evaluate the realism of the cyclists, the traffic, the city, the infrastructure, the car driven and the situations. Cyclists appeared in critical situations derived from previous accounts given by injured cyclists and from cyclists' observations in real-life situations. Cyclist's levels of visibility for car drivers were either high or low in these situations according to the cyclists.

RESULTS

Realism scores were similar and high in both groups. Cyclist-motorists had fewer collisions with cyclists and detected cyclists at a greater distance in all situations, irrespective of cyclist visibility. Several mechanisms underlying the cognitive conspicuity of cyclists for car drivers were considered.

CONCLUSION

The attentional selection of a cyclist in the road environment during car driving depends on top-down processing.

APPLICATION

We consider the practical implications of these results for the safety of vulnerable road users and future directions of research.

Cooperative warning systems: The impact of false and unnecessary alarms on drivers' compliance

Cooperative warning systems have a great potential to prevent traffic accidents. However, because of their predictive nature, they might also go along with an increased frequency of incorrect alarms that could limit their effectiveness. To better understand the consequences associated with incorrect alarms, a driving simulator study with N=80 drivers was conducted to investigate how situational context and warning urgency jointly influence drivers' compliance with an unreliable advisory warning system (AWS). The participants encountered several critical urban driving situations and were either assisted by a 100% reliable AWS, a 60% reliable AWS that generated false alarms (without obvious reason) or a 60% reliable AWS that generated unnecessary alarms (with plausible reason). A baseline drive without any assistance was also introduced to the study. The warnings were presented either only visually or visual-auditory. In line with previous research, drivers' compliance and effectiveness of the AWS was reduced by false alarms but not by unnecessary alarms. However, this so-called cry wolf effect (Breznitz, 1984) was only found in the visual-auditory condition, whereas there was no effect of warning reliability in the condition with visual AWS. Furthermore, false but not unnecessary alarms caused the participants to rate the AWS less favourably during a follow-up interview. In spite of these negative effects of false alarms, a reduction in the frequency of safety-critical events (SCEs) and an earlier braking onset were evident in all assisted drives compared with that of non-assisted driving, even when the AWS was unreliable. The results may thus lower concerns about the negative consequences of warning drivers unnecessarily about upcoming traffic conflicts if the reasons of these alarms are comprehensible. From a perspective of designing AWS, we recommend to use less urgent warnings to prevent the cry wolf effect.

Impact of North Carolina's motorcycle helmet law on hospital admissions and charges for care of traumatic brain injuries

BACKGROUND North Carolina requires motorcyclists of all ages to wear federally approved safety helmets. The purpose of this article is to estimate the impact of this state law in terms of hospital admissions for traumatic brain injury (TBI) and associated hospital charges. METHODS Hospital admissions of North Carolina motorcyclists with TBIs and associated hospital charges in 2011 were extracted from the North Carolina Hospital Discharge Data system. We estimated hospital admissions and charges for the same year under the counterfactual condition of North Carolina without a universal motorcycle helmet law by using various substitutes (Florida, Pennsylvania, and South Carolina residents treated in North Carolina). RESULTS North Carolina's universal helmet law prevented an estimated 190 to 226 hospital admissions of North Carolina motorcyclists with TBI in 2011. Averted hospital charges to taxpayer-funded sources (ie, government and public charges) were estimated to be between $9.5 million and $11.6 million for 2011, and total averted hospital charges for 2011 were estimated to be between $25.3 million and $31.0 million. LIMITATIONS Cost estimates are limited to inpatients during the initial period of hospital care. This study was unable to capture long-term health care costs and productivity losses incurred by North Carolina's TBI patients and their caregivers. CONCLUSIONS North Carolina's universal motorcycle helmet law generates health and economic benefits for the state and its taxpayers.

Injury incidence rates of cyclists compared to pedestrians, car occupants and powered two-wheeler riders, using a medical registry and mobility data, Rhône County, France

PURPOSE

In France, the bicycle's modal share is stabilizing after a decline; in some of France's major cities, it has even increased since the 1990s. It is hence relevant to improve the knowledge of the injury risk associated with cycling, compared with other means of transport such as car, walking and powered two-wheeler (PTW) riding.

METHODS

The injury incidence rates were estimated by the ratio between accident data and mobility (exposure) data. Two accident data sources were used: police data and hospital-based data (outpatients and inpatients) from the Rhône road trauma Registry. This provides four injury categories: all-injury, hospitalization, serious-injury and fatal-injury. Exposure data were estimated from a regional household travel survey (RTS), using three measures of mobility: number of trips, distance traveled and time spent traveling. The survey was carried out from November 2005 to April 2006, on weekdays, outside school and public holidays; this seasonality was corrected using the 2007-2008 national household travel survey (NTS) that covered an entire year. Only information involving accidents and trips in, and residents of, the Rhône County (1.6 million inhabitants, including the city Lyon) were included in our study. Trends of injury rates were also evaluated in Greater Lyon, using previous travel surveys.

RESULTS

The PTW riders had the highest all-injury, hospitalization, serious-injury and fatal-injury rates, followed by cyclists, and lastly by pedestrians and car occupants. The rates between men and women seemed similar among pedestrians and among car occupants. For car occupants, pedestrians and cyclists, the age group 18-25 years had higher all-injury rate compared with the age group 25-65 years. On the contrary, the age group≥65 years seemed to have higher hospitalization and serious-injury rates, compared with the age group 25-65 years. For cyclists, the injury rates seemed higher in non-dense areas than in dense areas. Between 1996-1997 and 2005-2006 and with regards to time spent traveling, the all-injury, serious-injury and fatal-injury rates seemed to have decreased for car occupants and cyclists.

CONCLUSION

The higher risk for PTW riders is confirmed and quantified; it is very high. Decrease in injury rates seems more marked for cyclists; this may indicate the "safety in numbers" effect. Countermeasures for improving road safety could be implemented, especially for vulnerable road user types. However, they will not be sufficient to fill in the gap between the much higher risk for PTW riders and that of car occupants. Exposure-based injury rates can be a tool for monitoring and evaluating the effectiveness of policies and programs, and for comparisons between countries.