Exploration of the tram-involved crashes' characteristics and contributing factors to fatality in tram crashes in Japan.

Modern trams have garnered worldwide attention as an alternative urban rail transit system since they offer advantages such as higher accessibility, convenience, lower construction and maintenance costs compared with subways. Nevertheless, due to the system's characteristics, particularly regarding right-of-way issues, crashes involving trams often lead to severe consequences. This study utilizes traffic crash data from across Japan, including 1,121,299 crashes that occurred from 2019 to 2022, of which 304 were tram involved.

Multivariate linear intervention models with random parameters to estimate the effectiveness of safety treatments: Case study of intersection device program.

A novel intervention model that analyzes time-series crash data was recently introduced in the road safety statistical field. The model allows the computation of components related to direct and indirect treatment effects using a linearized time-series intervention model. The isolation of a component corresponding to the direct treatment effects, known as the crash modification function (CMFunction), enables the assessment of safety countermeasures over time.

Evaluating the safety impact of increased speed limits on rural highways in British Columbia.

Maximum speed limits are usually set to inform drivers of the highest speed that it is safe and appropriate for ideal traffic, road and weather conditions. Many previous studies were conducted to investigate the relationship between changed speed limits and safety. The results of these studies generally show that relaxing speed limits can negatively affect safety, especially with regard to fatal and injury crashes.

A full Bayes before-after study accounting for temporal and spatial effects: Evaluating the safety impact of new signal installations.

Recently, important advances in road safety statistics have been brought about by methods able to address issues other than the choice of the best error structure for modeling crash data. In particular, accounting for spatial and temporal interdependence, i.e.

Developing crash modification functions for pedestrian signal improvement.

Pedestrian signals are viable traffic control devices that help pedestrians to cross safely at intersections. Although the literature is extensive when dealing with pedestrian signals design and operations, few studies have focused on the potential safety benefits of installing pedestrian signals at intersections. Most of these studies employed simple before-after (BA) safety evaluation techniques which suffer from methodological and statistical issues.

Investigating the accuracy of Bayesian techniques for before-after safety studies: the case of a "no treatment" evaluation.

The main challenge in conducting observational before-after (BA) studies of road safety measures is to use a methodology that accounts for many potential confounding factors. However, it is usually difficult to evaluate and decide on the accuracy of the different safety evaluation techniques available in literature. This is mainly because the outcome of the comparison has no specific target (i.

Accounting for heterogeneity among treatment sites and time trends in developing crash modification functions.

Collision modification factors (CMFs) are commonly used to quantify the impact of safety countermeasures. The CMFs obtained from observational before-after (BA) studies are usually estimated by averaging the safety impact (i.e.

Collision modification functions: incorporating changes over time.

Collision modification factors (CMFs) are considered the primary tools for estimating the effectiveness of safety treatments at road sites. Three main techniques are commonly used to estimate CMFs: the empirical Bayes (EB) method, the comparison-group (CG) method, and a combination of the EB and CG methods. CMF estimates from these techniques are usually provided with a measure of uncertainty of the estimate, in the form of standard error and confidence interval.

A comparison of collision-based and conflict-based safety evaluations: the case of right-turn smart channels.

This study presents the results of a collision-based full Bayes (FB) before-after (BA) safety evaluation of a newly proposed design for channelized right-turn lanes. The design which is termed "Smart Channels" decreases the angle of the channelized right-turn to approximately 70°. Its implementation is usually advocated to afford drivers a better view of the traffic stream they are to merge with and to allow also for safer pedestrian crossing.

Investigation of models for relating roundabout safety to predicted speed.

Despite widespread recognition of operating speed as a key safety-related variable for roundabouts, there is no consensus on the best models for capturing the relationship between crashes and speed, or, for that matter, on how speed can be estimated in situations where it cannot be observed (such as when a roundabout is being designed or redesigned). This paper uses US and Italian roundabout approach-level data to investigate models relating safety to various measures of predicted speed. This is an indirect approach for developing safety models for estimating the effects of design features, the premise being that these features can better predict speed, which, in turn, can be used as a predictor of crash frequency.