The article presents a review of recent literature on the performance metrics of Automated Driving Systems (ADS). More specifically, performance indicators of environment perception and motion planning modules are reviewed as they are the most complicated ADS modules. The need for the incorporation of the level of threat an obstacle poses in the performance metrics is described. A methodology to quantify the level of threat of an obstacle is presented in this regard. The approach involves simultaneously considering multiple stimulus parameters (that elicit responses from drivers), thereby not ignoring multivariate interactions. Human-likeness of ADS is a desirable characteristic as ADS share road infrastructure with humans. The described method can be used to develop human-like perception and motion planning modules of ADS. In this regard, performance metrics capable of quantifying human-likeness of ADS are also presented. A comparison of different performance metrics is then summarized. ADS operators have an obligation to report any incident (crash/disengagement) to safety regulating authorities. However, precrash events/states are not being reported. The need for the collection of the precrash scenario is described. A desirable modification to the data reporting/collecting is suggested as a framework. The framework describes the precrash sequences to be reported along with the possible ways of utilizing such a valuable dataset (by the safety regulating authorities) to comprehensively assess (and consequently improve) the safety of ADS. The framework proposes to collect and maintain a repository of precrash sequences. Such a repository can be used to 1) comprehensively learn and model the precrash scenarios, 2) learn the characteristics of precrash scenarios and eventually anticipate them, 3) assess the appropriateness of the different performance metrics in precrash scenarios, 4) synthesize a diverse dataset of precrash scenarios, 5) identify the ideal configuration of sensors and algorithms to enhance safety, and 6) monitor the performance of perception and motion planning modules.
1 January 2015 in Transportation Research Record: Journal of the Transportation Research Board
This paper evaluates the influence of on-street bike lanes on the lateral separation between motor vehicles and cyclists when the vehicle overtakes the cyclist and investigates the relationship between the passing behavior and traffic conditions. A bicycle was instrumented with a sensor array that consisted of an ultrasonic sensor, a GPS receiver, and a video camera. A total of 5,227 passing events were recorded across different categories of urban arterials. The results showed that the facilities with on-street bike lanes provided greater separation between bicycles and motor vehicles. Passing maneuvers with lateral separation of less than 1,000 mm (3.30 ft) were observed less frequently on the facilities with on-street bike lanes. Further, it was found that, in the absence of a bike lane, a higher proportion of passing vehicles moved laterally to the left and encroached on the adjacent lane. The analysis showed that for arterial roadways without on-street bike lanes, drivers tended to provide increased lateral clearance by either changing lanes or encroaching on the adjacent lane. However, drivers' ability to perform either of these maneuvers may be restricted by surrounding vehicles.
1 March 2024 in Canadian Journal of Civil Engineering
Resilience is a multidisciplinary concept that deals with rapid response and recovery of a system experiencing a disruption. Despite extensive research on this topic, there is a need to clarify resilience concepts in the context of road freight transportation systems (FTSs) from a three-dimensional perspective (i.e., physical infrastructure, users, and managing organizations) and to identify persistent knowledge gaps concerning the characterization and measurement of FTS resilience vis-à-vis disruptive events. This paper addresses these shortcomings through a systematic review of 149 research studies. The synthesis of findings clarifies inconsistencies associated with the characteristics of FTS resilience and in so doing, establishes a unified framework for measuring FTS resilience through the life cycle of disruptive events. Critical data gaps, methodological shortcomings, and a lack of empirical evidence concerning FTS resilience to disruptive events remain. More robust analytical approaches are required to incorporate interdependencies among FTS dimensions into resilience assessments.