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1.
Accid Anal Prev ; 160: 106298, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34358750

RESUMO

Three-fourths of pedestrian fatalities in the U.S. occur in the dark (National Center for Statistics and Analysis, 2020). Adaptive Headlight Systems (AHS) offer the potential to address this problem by improving the visibility of pedestrians for drivers and alerting pedestrians to approaching vehicles. The goal of this study was to investigate how pedestrians respond to different types of AHS. We conducted a mixed factor experiment with 106 college-age adults using a large-screen pedestrian simulator. The task for participants was to cross a stream of continuous traffic without colliding with a vehicle. There were four AHS treatment conditions that differed in the color (white or red) and timing of an icon projected on the roadway in front the participant as an AHS vehicle approached. Participants in the treatment conditions encountered a mix of AHS and non-AHS vehicles. There was also a control condition in which participants encountered only non-AHS vehicles. We found that the color and the timing of the icon projected on the roadway influenced the size of the gaps crossed. Participants in the red icon with early onset condition chose the largest gaps for crossing. An unexpected outcome was that participants in the AHS treatment conditions chose larger gaps even when crossing in front of non-AHS vehicles, suggesting that experiences with AHS vehicles generalized to non-AHS vehicles. We conclude that AHS can have a significant, positive impact on pedestrian road-crossing safety.


Assuntos
Pedestres , Acidentes de Trânsito/prevenção & controle , Adulto , Humanos , Segurança , Caminhada
2.
Accid Anal Prev ; 160: 106315, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34363992

RESUMO

The dramatic increase in road traffic accidents poses social and economic challenges to nations, especially for developing countries. Thus, road safety urgently needs to be significantly improved at the national level to reduce the number of road traffic accidents and costs associated with it. Understanding road users' acceptance of road pricing regarding road safety improvement is crucial for safety-related investment programs. As such, this paper investigated the factors associated with public intention-to-pay (ITP) for road safety improvement in Pakistan. A structural equation model (SEM) was adopted to analyze the determinants of ITP according to the theory of planned behavior (TPB) combined with latent psychological variables that describe the personal characteristics and evaluations of different measures. Furthermore, the moderating effects of socioeconomic characteristics were also examined. A sample of 340 car drivers, interviewed at different locations of Peshawar, Pakistan, was used to test the model. Results of the SEM model indicated that Road Infrastructure Safety Perception and Perceived Behavioral Control have strong association with the ITP of car users' for road safety improvement. Risk Perception, Attitude towards Traffic Safety Responsibility, Attitude, Perceived Fairness, and Perceived Effectiveness were also associated with ITP. Differential age and gender-related moderating effects were also observed. Findings from this study are expected to assist the decision-makers in the effective planning and implementation of road safety projects and related budget allocations.


Assuntos
Acidentes de Trânsito , Intenção , Acidentes de Trânsito/prevenção & controle , Atitude , Humanos , Paquistão , Segurança , Inquéritos e Questionários
3.
Accid Anal Prev ; 160: 106313, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34365043

RESUMO

The American Association of State Highway and Transportation Officials' Highway Safety Manual (HSM) includes a collection of safety performance functions (SPFs) or statistical models to estimate the expected crash frequency of roadway segments, intersections, and interchanges. These models are applied in several steps of the safety management process, including to screen the road network for opportunities to improve safety and to evaluate the performance of safety countermeasure deployments. The SPFs in the HSM are generally estimated using negative binomial regression modeling. In some instances, they are estimated using annual crash frequency and site-specific (e.g., traffic volume) data, while in other instances they are estimated using aggregate crash frequency and site-specific data. This paper explores the differences that result from estimating SPFs using aggregate versus disaggregate data using the same methods as those used to estimate the SPFs in the HSM. A synthetic dataset was first used to conduct these comparisons - these data were generated in a manner that is consistent with the properties of the negative binomial distribution. Then, an observational dataset from Pennsylvania was used to compare the SPFs from both aggregate and disaggregate data. The results show that SPFs estimated using the panel (disaggregate) data and aggregated data provide similar model coefficients, although some differences may sometimes arise. However, the overdispersion parameter obtained using each dataset can differ significantly. These differences result in systematic biases in calculations of expected crash frequency when Empirical Bayes adjustments are applied, which - as the paper demonstrates - could lead to different outcomes in a network screening exercise. Overall, these results reveal that aggregating crash data might result in biased SPF outputs and lead to inconsistent Empirical Bayes adjustments.


Assuntos
Agregação de Dados , Planejamento Ambiental , Acidentes de Trânsito/prevenção & controle , Teorema de Bayes , Humanos , Modelos Estatísticos , Segurança , Gestão da Segurança
4.
Artigo em Inglês | MEDLINE | ID: mdl-34444563

RESUMO

Crosswalks are critical locations in the urban transport network that need to be designed carefully as pedestrians are directly exposed to vehicular traffic. Although various methods are available to evaluate the level of service (LOS) at pedestrian crossings, pedestrian crossing facilities are frequently ignored in assessing crosswalk conditions. This study attempts to provide a comprehensive framework for evaluating crosswalks based on several essential indicators adopted from different guidelines. A new pedestrian crossing level of service (PCLOS) method is introduced in this research, with an aimto promote safe and sustainable operations at such locations. The new PCLOS employs an analytical point system to compare existing street crossing conditions to the guidelines' standards, taking into account the scores and coefficients of the indicators. The quantitative scores and coefficients of indicators are assigned based on field observations and respondent opinions. The method was tested to evaluate four pedestrian crosswalks in the city of Putrajaya, Malaysia. A total of 17 indicators were selected for the study after a comprehensive literature review. Survey results show that the provision of a zebra crossing was the most critical indicator at the pedestrian crossings, while drainage near crosswalks was regarded as the least important. Four indicators had a coefficient value above 4, indicating that these are very critical pedestrian crossing facilities and significantly impact the calculation of LOS for pedestrian crossings. Four crosswalks were evaluated using the proposed method in Putrajaya, Malaysia. The crosswalk at the Ministry of Domestic Trade Putrajaya got the "PCLOS A". In contrast, the midblock crossing in front of the Putrajaya Corporation was graded "PCLOS C". While the remaining two crosswalks were graded as "PCLOS B" crosswalks. Based on the assigned PCLOS grade, the proposed method could also assist in identifying current design and operation issues in existing pedestrian crossings and providing sound policy recommendations for improvements to ensure pedestrian safety.


Assuntos
Neuropeptídeos , Pedestres , Acidentes de Trânsito/prevenção & controle , Cidades , Proteínas do Citoesqueleto , Humanos , Segurança , Caminhada
6.
MMWR Morb Mortal Wkly Rep ; 70(31): 1053-1058, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34351881

RESUMO

As of July 30, 2021, among the three COVID-19 vaccines authorized for use in the United States, only the Pfizer-BioNTech BNT162b2 mRNA COVID-19 vaccine is authorized for adolescents aged 12-17 years. The Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for Pfizer-BioNTech vaccine for use in persons aged ≥16 years on December 11, 2020 (1); the EUA was expanded to include adolescents aged 12-15 years on May 10, 2021 (2), based on results from a Phase 3 clinical trial (3). Beginning in June 2021, cases of myocarditis and myopericarditis (hereafter, myocarditis) after receipt of Pfizer-BioNTech vaccine began to be reported, primarily among young males after receipt of the second dose (4,5). On June 23, 2021, CDC's Advisory Committee on Immunization Practices (ACIP) reviewed available data and concluded that the benefits of COVID-19 vaccination to individual persons and the population outweigh the risks for myocarditis and recommended continued use of the vaccine in persons aged ≥12 years (6). To further characterize safety of the vaccine, adverse events after receipt of Pfizer-BioNTech vaccine reported to the Vaccine Adverse Event Reporting System (VAERS) and adverse events and health impact assessments reported in v-safe (a smartphone-based safety surveillance system) were reviewed for U.S. adolescents aged 12-17 years during December 14, 2020-July 16, 2021. As of July 16, 2021, approximately 8.9 million U.S. adolescents aged 12-17 years had received Pfizer-BioNTech vaccine.* VAERS received 9,246 reports after Pfizer-BioNTech vaccination in this age group; 90.7% of these were for nonserious adverse events and 9.3% were for serious adverse events, including myocarditis (4.3%). Approximately 129,000 U.S. adolescents aged 12-17 years enrolled in v-safe after Pfizer-BioNTech vaccination; they reported local (63.4%) and systemic (48.9%) reactions with a frequency similar to that reported in preauthorization clinical trials. Systemic reactions were more common after dose 2. CDC and FDA continue to monitor vaccine safety and provide data to ACIP to guide COVID-19 vaccine recommendations.


Assuntos
Vacinas contra COVID-19/efeitos adversos , Segurança , Adolescente , Sistemas de Notificação de Reações Adversas a Medicamentos , Criança , Feminino , Humanos , Masculino , Miocardite/epidemiologia , Medição de Risco , Estados Unidos/epidemiologia , Vacinas Sintéticas/efeitos adversos
7.
Sensors (Basel) ; 21(15)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34372240

RESUMO

The emerging connected and automated vehicle (CAV) has the potential to improve traffic efficiency and safety. With the cooperation between vehicles and intersection, CAVs can adjust speed and form platoons to pass the intersection faster. However, perceptual errors may occur due to external conditions of vehicle sensors. Meanwhile, CAVs and conventional vehicles will coexist in the near future and imprecise perception needs to be tolerated in exchange for mobility. In this paper, we present a simulation model to capture the effect of vehicle perceptual error and time headway to the traffic performance at cooperative intersection, where the intelligent driver model (IDM) is extended by the Ornstein-Uhlenbeck process to describe the perceptual error dynamically. Then, we introduce the longitudinal control model to determine vehicle dynamics and role switching to form platoons and reduce frequent deceleration. Furthermore, to realize accurate perception and improve safety, we propose a data fusion scheme in which the Differential Global Positioning system (DGPS) data interpolates sensor data by the Kalman filter. Finally, a comprehensive study is presented on how the perceptual error and time headway affect crash, energy consumption as well as congestion at cooperative intersections in partially connected and automated traffic. The simulation results show the trade-off between the traffic efficiency and safety for which the number of accidents is reduced with larger vehicle intervals, but excessive time headway may result in low traffic efficiency and energy conversion. In addition, compared with an on-board sensor independently perception scheme, our proposed data fusion scheme improves the overall traffic flow, congestion time, and passenger comfort as well as energy efficiency under various CAV penetration rates.


Assuntos
Condução de Veículo , Acidentes de Trânsito , Simulação por Computador , Humanos , Segurança
8.
Narrat Inq Bioeth ; 11(1): 55-59, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34334469

RESUMO

The COVID-19 pandemic disrupted and displaced the old normal, necessitating adaptation. The narratives in this issue of NIB give us a glimpse into the experience of conducting research during a pandemic. The authors were on a mission to pursue research despite the challenges the pandemic imposed. They described difficulties of the Institutional Review Board process and the necessity of asking for accelerated IRB approval. The authors also discussed challenges they faced with research participant recruitment during a pandemic and concerns about keeping staff safe from the risk of transmission. The authors adapted and adjusted to the personal and professional restraints the COVID-19 pandemic placed upon them. Despite these difficulties, the authors remained committed to maintaining the integrity of their research.


Assuntos
Atitude do Pessoal de Saúde , Pesquisa Biomédica , COVID-19 , Pandemias , Pesquisadores , Pesquisa Biomédica/ética , Comitês de Ética em Pesquisa , Ética em Pesquisa , Humanos , Narração , Seleção de Pacientes , SARS-CoV-2 , Segurança
9.
Narrat Inq Bioeth ; 11(1): 95-99, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34334483

RESUMO

This commentary discusses twelve stories in which people who are involved in institutional review board (IRB) administration or serve as IRB members tell the stories of how the COVID-19 pandemic affected their work and lives. Among the aspects of these stories it highlights are the need to focus on the well-being of the institution's employees, and how issues involving protecting vulnerable subjects might relate to current policy debates about underserved communities. The final portion of this commentary focuses in particular on how one might measure success for a program in protecting its research subjects during a pandemic.


Assuntos
COVID-19 , Comitês de Ética em Pesquisa , Saúde do Trabalhador , Pandemias , Sujeitos da Pesquisa , Segurança , Humanos , Narração , Políticas , SARS-CoV-2 , Populações Vulneráveis
10.
Brasília, D.F.; OPAS; 2021-08-02.
Não convencional em Português | PAHO-IRIS | ID: phr2-54577

RESUMO

O objetivo deste sumário de políticas é fornecer uma perspectiva relevante a partir de evidências comportamentais e um conjunto de considerações comportamentais para aqueles que planejam as iniciativas que incentivam os comportamentos preventivos da COVID-19 entre os jovens. Realizou-se uma revisão rápida e não sistemática das evidências para examinar se os jovens – amplamente definidos na revisão como indivíduos entre 15 e 30 anos de idade – são suficientemente diferentes dos grupos etários mais velhos em sua percepção de risco e tomada de decisão de modo a justificar uma abordagem mais específica. A revisão concluiu que, nas idades compreendidas como a metade da adolescência, os processos cognitivos de tomada de decisão dos jovens são semelhantes aos dos adultos em muitos aspectos; no entanto, existem alguns fatores comportamentais que influenciam os comportamentos de risco ou os comportamentos pouco seguros que são particularmente relevantes entre os jovens.


Assuntos
COVID-19 , Comportamento , Comportamento do Adolescente , Coronavirus , Comportamentos de Risco à Saúde , Segurança , Redes Sociais Online , Prevenção de Doenças , Política de Saúde
11.
Accid Anal Prev ; 159: 106272, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34214914

RESUMO

The significance of commuting with ebikes as an integral part of the urban mobility of the future can no longer be ignored. The real and perceived hazards of cycling in urban areas and sharing roads with other motorized vehicles have been identified as a major barrier to wider adoption of ebikes. The objective of this study is to investigate parameters that affect the anxiety level of cyclists, which influences their safety and interaction with other road users. An ebike was instrumented with a variety of sensors and equipment to monitor the speed, balance of bike, type, and proximity of vehicles overtaking cyclists, as well as the events on the road. Thirty-two participants rode the instrumented ebike for 12 km on urban roads in Oshawa, ON, Canada. Participants wore a heart rate sensor attached to their chest and a helmet equipped with a peripheral detection task setup to measure stress and mental workload. This naturalistic study showed that most participants had concerns about the threats and risks of crashes when sharing the road with other vehicles. The data showed that the significant difference in acceleration between ebikes and conventional bikes does not change the perception of safety for cyclists. Additionally, the outcomes indicate that mental workload and average heart rate increase at lower speeds when passing a queue of vehicles in traffic or at intersections. Across all participants, the balance of the bike did not change significantly. Also, neither the heart rate nor mental workload showed a significant effect on the balance of the bike. This study suggests that dense traffic in the afternoon and the demands of riding a bike in complex traffic conditions result in a higher mental workload even though cyclists slowed down their speeds. Furthermore, the majority reported perceived risks of cycling on a shared road with other vehicles regardless of the demographic differences. The findings from this study can be used as a framework for the development of active safety features for ebikes.


Assuntos
Acidentes de Trânsito , Ciclismo , Aceleração , Acidentes de Trânsito/prevenção & controle , Ansiedade , Humanos , Segurança , Transportes
12.
Accid Anal Prev ; 159: 106279, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34218198

RESUMO

Roadway lighting is used to ensure nighttime safety and security for multimodal road users. However, the absence of reliable quantitative analyses of the safety effects of roadway lighting photometric characteristics prevents accurate assessment of street lighting maintenance and retrofitting projects. This study aimed to investigate the relationship between nighttime crash risk and two critical photometric criteria, i.e., average lighting level and uniformity. To achieve this goal, high-resolution horizontal illuminance data were collected in Florida for 300 + center-miles from 2011 to 2014. Based on the data, a matched case-control study was conducted to address two major issues existing in previous studies: (1) the confounding effects of illuminance standard deviation on illuminance mean and (2) spatially-unrelated extreme values for ratio-based uniformity. By eliminating the confounding effects through a random matching strategy (one case, a segment with nighttime crashes, to one control, a segment without nighttime crashes at 1,046 strata), this study successfully isolated the negative effects of the standard deviation and developed more significant crash modification factors (CMFs) for average lighting levels: 0.679 for increasing the average lighting level from [0 fc, 0.5 fc] to (0.5 fc, 1.0 fc] and 0.581 for increasing the average lighting from [0 fc, 0.5 fc] to higher than 1.0 fc. Additionally, a CMF of 1.391 for a max-min ratio greater than 10 was identified by controlling the segment length at a short uniform unit (1,200 ft). The developed CMFs overcame the underestimation issue in previous studies and are implementable in current street lighting design and safety management.


Assuntos
Acidentes de Trânsito , Planejamento Ambiental , Estudos de Casos e Controles , Humanos , Iluminação , Segurança
13.
Accid Anal Prev ; 159: 106274, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34242860

RESUMO

Limitations of historical crash data and the advantages of surrogate measures of safety have already been stressed by various authors. To describe nearness-to-collision, mostly time-based indicators are applied, and there is a consensus among researchers that speed-related indicators are needed to account for the severity dimension. There have been attempts to fit bivariate Extreme Value models to predict the number of crashes, however modeling crash frequency together with severity has received much less attention. The aim of this paper is to apply Extreme Value models to various pairs of temporal and speed-related indicators in order to investigate the dependence structure between them as well as to construct probability based risk levels and examine them in relation to severity levels. Bivariate threshold excess models were fitted to a dataset of left-turning and straight moving vehicle interactions recorded in a signalized intersection. The dependence structure between variable pairs were thoroughly investigated; it was concluded that temporal and speed related indicators were found independent, which means that road users getting close to each other in time does not necessarily come with high speeds. Therefore these indicators should be combined in order to properly predict severity; a temporal indicator on its own is not enough to make inferences about the severity of events. Using the calculated joint probability of events risk levels were constructed illustrating the events of equal probability.


Assuntos
Acidentes de Trânsito , Condução de Veículo , Acidentes de Trânsito/prevenção & controle , Consenso , Humanos , Probabilidade , Registros , Segurança
14.
Accid Anal Prev ; 159: 106284, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34242862

RESUMO

Work zones are established to provide a safe environment for all road users and road workers. However, based on the statistics, they can be considered as crash prone zones due to changes in the road alignments and the posted speed limits. In this driving simulator study, we aimed at investigating the safety impacts of a newly proposed system composed of graphical and animation-based variable message signs (VMSs) in the state of Qatar. The proposed VMS condition was compared with a control condition that was designed following the Qatar Work Zone Traffic Management Guide. A total of seventy subjects were invited to participate in the experiment voluntarily. Study results showed that in the VMS condition, drivers reduced their traveling speeds in advanced compared to the control condition. Drivers' traveling speed in the VMS condition was significantly reduced by 6.3 and 11.1 km/h on the leftmost and the second leftmost lanes, respectively. Next, the results uncovered that the proposed system motivated drivers to initiate early lane changing maneuvers, i.e., 150 m earlier than the control condition. Finally, the VMS condition was effective in stimulating drivers to keep larger headways with a merging vehicle. In sum, the proposed VMS system outperformed the control condition in terms of speed reduction, early merging, and higher headways between the through and the merging vehicle.


Assuntos
Acidentes de Trânsito , Condução de Veículo , Acidentes de Trânsito/prevenção & controle , Humanos , Catar , Segurança
15.
Accid Anal Prev ; 159: 106276, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34242863

RESUMO

The actual speed behaviour when drivers approach a curve is very relevant to assess the road design and safety but is mostly overlooked in the scientific literature. Most research into curve driving behaviour is focussed at the behaviour inside the curve, although the speed selection is done before curve entry. The main objective of this research is to identify which freeway characteristics play a role in driving speed selection. High Frequency Floating Car Data, detailed reconstruction of the curves and their surroundings, as well as three dimensional sight distance analysis, were used to analyse individual speed profiles on 153 Dutch freeway curves. By defining the positions where the acceleration approaches 0 m/s2 before and after a curve starts, the positions when the driver started and stopped decelerating upon curve entry were defined. Further correlation and regression analysis of those positions revealed that the radius of the curve is indeed a main explaining variable, as well as the speed driven before deceleration starts. Sight distances and cross section characteristics play a further role in determining the position where deceleration starts. Deceleration ends at approximately 135 m after curve start, and the speed in a curve is also correlated with the deflection angle and length of a curve. Sight distances do not play a role in selecting the speed in a curve based on this research. Overall, the findings indicate a non-constant nature and variability of speed behaviour upon curve entry. This can be used for safer freeway curve design and to assess traffic safety based on actual speed behaviour.


Assuntos
Acidentes de Trânsito , Condução de Veículo , Aceleração , Planejamento Ambiental , Grupos Étnicos , Humanos , Segurança
16.
Accid Anal Prev ; 159: 106290, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34246056

RESUMO

Smartphones are nowadays indispensable devices in daily life. Their rapid technological development makes it possible to have almost all necessary information on them, which facilitates their spread among all users. However, this extensive use has led to many distraction problems while performing other main tasks, such as activities on the road, which can also impact people's safety. Therefore, various experts focused their attention on issues related to drivers looking at their mobile phones; recently, researchers from different disciplines saw the need to deepen knowledge also on the phenomenon of vulnerable road users distracted by digital devices, especially when approaching signalized intersections. This study builds on and seeks to extend this area of research by analyzing the effects of digital distraction on pedestrians as they approach unsignalised intersections located on roundabout entrances and exits. The aim of the research is to understand the extent to which the task of checking social media affects pedestrian reaction and crossing times, as well as to identify which elements attract the most pedestrian attention. To achieve this goal, an eye-tracking study was designed, in which participants wearing eye-tracking glasses were asked to walk a predefined route, once checking their social media apps and once walking without distracting technological elements. The results showed an 84% increase in reaction time when using the phone, while only a slight rise in crossing time was found. The general conclusions about the most observed elements when walking are also consistent with the main findings of previous literature studies.


Assuntos
Telefone Celular , Pedestres , Acidentes de Trânsito/prevenção & controle , Humanos , Segurança , Caminhada
17.
Accid Anal Prev ; 159: 106288, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34246877

RESUMO

A critical safety problem in road networks is the conflicts on unsignalized crosswalks. Thus, a proactive approach to assess pedestrian safety performance is required. Simulating the microscopic road user behavior in a virtual platform is one of the typical approaches. However, current simulation tools are not flexible enough to properly reproduce various behaviors of pedestrians and drivers considering their interactions with the road environment and other road users. Therefore, the objective of this paper is to propose a novel agent-based framework for evaluating pedestrian safety at unsignalized crosswalks. Unsignalized mid-block crosswalks with refuge islands (UMCR) are considered as an example facility to implement the proposed framework, where relevant behavioral elements such as the reaction time, visual field with obstacles, and minimum safety margin time are addressed. Not only the pedestrian-vehicle interaction is modeled but also the vehicle-vehicle interaction is considered. Empirical validation on a UMCR shows that the proposed framework can reproduce reliable distributions of the post encroachment time compared to the observed distributions within an acceptable error range. The sensitivity analysis reveals that the high reaction time of drivers, small safety margin time, and visual obstacles near crosswalks increase the probability of serious conflicts. The results also show that the framework can reproduce traffic crashes under assumed extreme road conditions.


Assuntos
Pedestres , Acidentes de Trânsito/prevenção & controle , Humanos , Probabilidade , Tempo de Reação , Segurança , Caminhada
18.
Accid Anal Prev ; 159: 106294, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34252582

RESUMO

This research develops safety performance functions and identifies the crash hotspots based on estimated vulnerable road users' exposure at intersections and along the roadway segments. The study utilized big data including Automated Traffic Signal Performance Measures (ATSPM) data, crowdsourced data (Strava), Closed Circuit Television (CCTV) surveillance camera videos, crash data, traffic information, roadway features, land use attributes, and socio-demographic characteristics. It comprises an extensive comparison between a wide array of statistical and machine learning models that were developed to estimate pedestrian and bike exposure. The results indicated that the XGBoost approach was the best to estimate vulnerable road users' exposure at intersections as well as bike exposure along the roadway segments. Afterwards, the estimated exposure was utilized as input variables to develop crash prediction models that relate different crash types to potential explanatory variables. Negative Binomial approach was followed to develop crash prediction models to be consistent with the Highway Safety Manual. The results show that the exposure variables (i.e., AADT, bike exposure, and the interaction between them) have significant influences on the two types of crashes (i.e., crashes of vulnerable road users at intersections and bike crashes along the segments). Further, the results indicated that the context classification is significantly related to crashes. Based on the developed models, the PSIs were calculated and the hotspots were identified for the two crash types. It was found that hotspots were more likely to be located near the city of Orlando. Coastal roadways were classified as cold categories regarding bike crashes. Further, C4 roadway segments were found to be significantly related to the increase of vulnerable road users' crashes at intersections and bike crashes along the segments.


Assuntos
Acidentes de Trânsito , Pedestres , Planejamento Ambiental , Humanos , Modelos Estatísticos , Segurança
19.
Accid Anal Prev ; 159: 106287, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34256314

RESUMO

The transportation safety paradigm for urban transportation - particularly safety for those walking and cycling - relies on counting crashes to parameterize safety. These objective measures of safety are spatially static and reflective of past events: they can be enriched by including the human response to risk at diverse infrastructure designs. This perceived risk has been well captured qualitatively in the transportation safety literature; in the following study, we seek to develop a quantitative methodology that captures perceived risk as a continuous measure of human biometrics. Building on diverse safety-critical fields, we hypothesize that the perception of safety can be measured proactively with traveler biometrics, including eye and head movements, such that high readings of biometric indicators correlate with less safe areas. We collect biometric data from cyclists traversing an urban corridor with a protected, yet not continuously, cycle lane. By isolating and correlating peaks in cyclist biometric measures with infrastructure design, we develop a set of continuous variables - lateral head movements, gaze velocity, and off-mean gaze distance, both independently and as a vector - that allow for the evaluation of urban infrastructure based on perceived risk. The results reflect that higher biometric readings correspond to less safe (i.e., unprotected) areas, indicating that perceived risk can be measured proactively with biometric data.


Assuntos
Acidentes de Trânsito , Benchmarking , Acidentes de Trânsito/prevenção & controle , Ciclismo , Humanos , Segurança , Transportes
20.
Accid Anal Prev ; 159: 106295, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34273623

RESUMO

Protected or separated bike lanes or cycle tracks, are increasing in popularity in North America and Europe. However, despite their documented benefits, there are concerns about potential conflicts between bicycles and vehicles when they merge back together at an intersection. The concern is that following a period of separation, drivers are less likely to anticipate and scan for the presence of bicyclists. This research examines how transitions from fully separated to mixed-traffic environments and vice versa affect driver behavior. The goal is to assess whether certain segment-intersection treatment combinations can alert drivers of the presence of bicyclists and thus, encourage them to scan for bicyclists prior to a right turn, reducing potential right-hook conflicts. Driving simulation is utilized and driver performance for right-turning vehicles is recorded under the presence of various bicycle infrastructure treatments along segments and at intersections. The experimental design includes conventional and protected bike lanes and intersections with either intersection crossing markings or protected intersections. The results show that the presence of protected bike lanes motivates fewer glances towards bicyclists traveling on those bike lanes, therefore, reducing drivers' ability to detect and in turn, perceive bicyclists. Drivers developed slightly lower speeds while driving next to protected versus conventional bike lanes. It was also found that protected intersections result in a higher rate of right glances at the intersection prior to a right turn. Drivers glancing at the intersection were also found to have lower speeds, indicating a correlation between the presence of protected intersection elements and speed selection. This research can be used to guide decisions on bicycle infrastructure implementation for safer multimodal operations.


Assuntos
Condução de Veículo , Ciclismo , Acidentes de Trânsito/prevenção & controle , Planejamento Ambiental , Humanos , Segurança
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