The relationship between driving volatility in time to collision and crash-injury severity in a naturalistic driving environment

Wali, Behram; Khattak, Asad J.; Karnowski, Thomas P.

doi:10.1016/j.amar.2020.100136

Cited by 41 publications

(18 citation statements)

References 86 publications

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“…All the variables were tested as random parameters. Following relevant literature ( Fountas, Anastasopoulos, & Mannering, 2018 ; Wali et al, 2020 ), a parameter underlying an explanatory variable was treated as a random parameter if it exhibited (1) statistically significant mean and standard deviation, or (2) exhibited statistically significant standard deviation but only when the AIC/BIC of the model was lower than (indicating better fit) the corresponding model treating the particular variable as fixed. The second standard used reflects a situation where substantial directional heterogeneity (positive and negative associations) is present captured by statistically significant standard deviation terms.…”

Section: Resultsmentioning

confidence: 99%

“…To perform the hierarchical integrations over densities for latent/unobserved factors, we used 200 scrambled Halton draws in the simulation process ( Train, 2009 ). Compared to the use of traditional Monte Carlo draws in approximating the integrals, variance reduction-based Halton draws were used providing better results by enhancing the coverage and covariance ( Train, 2009 ; Wali, Khattak, & Karnowski, 2020 ). Finally, regarding the functional form characterizing unobserved heterogeneity parameters, we tested different densities such as normal, lognormal, triangular, uniform, and Weibull distributions (discussed in the next section).…”

Section: Methodsmentioning

confidence: 99%

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Treating two pandemics for the price of one: Chronic and infectious disease impacts of the built and natural environment

Frank

Wali²

2021

Sustainable Cities and Society

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Compact walkable environments with greenspace support physical activity and reduce the risk for depression and several obesity-related chronic diseases, including diabetes and heart disease. Recent evidence confirms that these chronic diseases increase the severity of COVID-19 infection and mortality risk. Conversely, denser transit supportive environments may increase risk of exposure to COVID-19 suggesting the potential for contrasting chronic versus infectious disease impacts of community design. A handful of recent studies have examined links between density and COVID-19 mortality rates reporting conflicting results. Population density has been used as a surrogate of urban form to capture the degree of walkability and public transit versus private vehicle travel demand. The current study employs a broader range of built environment features (density, design, and destination accessibility) and assesses how chronic disease mediates the relationship between built and natural environment and COVID-19 mortality. Negative and significant relationships are observed between built and natural environment features and COVID-19 mortality when accounting for the mediating effect of chronic disease. Findings underscore the importance of chronic disease when assessing relationships between COVID-19 mortality and community design. Based on a rigorous simulation-assisted random parameter path analysis framework, we further find that the relationships between COVID-19 mortality, obesity, and key correlates exhibit significant heterogeneity. Ignoring this heterogeneity in highly aggregate spatial data can lead to incorrect conclusions with regards to the relationship between built environment and COVID-19 transmission. Results presented here suggest that creating walkable environments with greenspace is associated with reduced risk of chronic disease and/or COVID-19 infection and mortality.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Treating two pandemics for the price of one: Chronic and infectious disease impacts of the built and natural environment

Frank

Wali²

2021

Sustainable Cities and Society

Self Cite

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“…Li et al [24] presented a surrogate safety measure for pedestrian crashes based on GPS trajectory data. Furthermore, the previous studies linked the traffic volatility with crashes [26][27][28]. Wali et al [26,27] explored the relationship between driving volatility and crashes at intersections and segments.…”

Section: Proactive Safety Studies On Pedestriansmentioning

confidence: 99%

“…Furthermore, the previous studies linked the traffic volatility with crashes [26][27][28]. Wali et al [26,27] explored the relationship between driving volatility and crashes at intersections and segments. Zheng et al [28] connected the traffic conflicts to crash risk to predict crashes at signalized intersections.…”

Section: Proactive Safety Studies On Pedestriansmentioning

confidence: 99%

Real Time Safety Model for Pedestrian Red-Light Running at Signalized Intersections in China

Yin

2021

Sustainability

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The traditional way to evaluate pedestrian safety is a reactive approach using the data at an aggregate level. The objective of this study is to develop real-time safety models for pedestrian red-light running using the signal cycle level traffic data. Traffic data for 464 signal cycles during 16 h were collected at eight crosswalks on two intersections in the city of Nanjing, China. Various real-time safety models of pedestrian red-light running were developed based on the different combination of explanatory variables using the Bayesian Poisson-lognormal (PLN) model. The Bayesian estimation approach based on Markov chain Monte Carlo simulation is utilized for the real-time safety models estimates. The models’ comparison results show that the model incorporated exposure, pedestrians’ characteristics and crossing maneuver, and traffic control and crosswalk design outperforms the model incorporated exposure and the model incorporated exposure, pedestrians’ characteristics, and crossing maneuver. The result indicates that including more variables in the real-time safety model could improve the model fit. The model estimation results show that pedestrian volume, ratio of males, ratio of pedestrians on phone talking, pedestrian waiting time, green ratio, signal type, and length of crosswalk are statistically significantly associated with the pedestrians’ red-light running. The findings from this study could be useful in real-time pedestrian safety evaluation as well as in crosswalk design and pedestrian signal optimization.

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“…Various factors are involved in the occurrence of road collisions, of which human factors are considered the most significant [2]. To better design behavioral countermeasures, it should be well understood the driving behavior which are involved in safety critical events [3]. One of this behaviors is the adopted distance during driving which can be expressed in TH or distnace.…”

Section: Introductionmentioning

confidence: 99%

Comparing time to collision and time headway as safety criteria

Khansari¹,

Nejad²,

Moogehi³

2021

Pamukkale J Eng Sci

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Examination of the criteria for maintaining distance between vehicles helps to better understand the behavior of following behavior and traffic flow. In this study, time headway(TH) and time to collision(TTC) criteria have been studied using driving simulator. TH is divided into two types, including braking TH, TH at the moment of considerable brake, and following TH, TH during following. The results showed that by reaching TTC to a threshold, braking TH has increased to 1.5 sec. and after this value, braking TH has remained constant. Also the comparison between braking and following TH showed that, unlike following TH, braking TH has less variance and its values did not differ significantly between lanes. That is, the driver is trying to observe a fixed amount of braking TH, 1.1 seconds, all the time, and not get closer to the front vehicle accordingly. It can be said that among the criteria, braking TH is the most important factor and considering it can be helpful in the carfollowing models. Araçlar arasındaki mesafeyi korumak için kriterlerin incelenmesi yolun üzerindeki davranışları ve trafik akımını daha iyi anlamaya destek olur.Bu çalışmada zaman aralığı ve çarpışma süresi kriterleri sürüş simülatörü kullanarak incelenmiştir. Zaman aralığı, frenleme zaman aralığı ve takip zaman aralığı'na ayrılır. Sonuçlar çarpışma zamanının(TTC) bir eşiğe ulaşmasıyla ve frenleme zaman aralığının(TH) 1.5 sn.'ye yükseldiğini ve bu değerden sonra sabit kaldığını gösterdi. Ayrıca, frenleme zaman aralığı ve takip zaman aralığı arasında karşılaştırma, zaman aralığı'nı takip etmekten farklı olarak, frenleme zaman aralığı'nin daha az varyansa sahip olduğunu ve değerlerinin şeritler arasında önemli ölçüde farklılık göstermediğini gösterdi. Yani sürücü her zaman 1.1 sn. sabit bir frenleme zaman aralığısı gözlemlemeye çalışıyor ve buna göre ön araca yaklaşmıyor kriterler arasında zaman aralığı frenleme'nin en önemli faktör olduğu ve bunun dikkate alınması otomobil takip eden modellerde faydalı olabileceği söylenebilir.

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The relationship between driving volatility in time to collision and crash-injury severity in a naturalistic driving environment

Cited by 41 publications

References 86 publications

Treating two pandemics for the price of one: Chronic and infectious disease impacts of the built and natural environment

Treating two pandemics for the price of one: Chronic and infectious disease impacts of the built and natural environment

Real Time Safety Model for Pedestrian Red-Light Running at Signalized Intersections in China

Comparing time to collision and time headway as safety criteria

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