Luigi Pariota

ABSTRACT Studies of driving behaviour are of great help for different tasks in transportation engineering. These include data collection both for statistical analysis and for identification of driving models and estimation of modelling parameters (calibration). The data and models may be applied to different areas: i) road safety analysis; ii) microscopic models for traffic simulation, forecast and control; iii) control logics aimed at ADAS (Advanced Driving Assistance Systems). In this paper we present a large survey based on the naturalistic (on-the-road) observation of driving behaviour with a view to obtaining microscopic data for single vehicles on long road segments and for long time periods. Data are collected by means of an instrumented vehicle (IV), equipped with GPS, radar, cameras and other sensors. The behaviour of more than 100 drivers was observed by using the IV in active mode, that is by observing the kinematics imposed on the vehicle by the driver, as well as the kinematics with respect to neighbouring vehicles. Sensors were also mounted backwards on the IV, allowing the behaviour of the driver behind to be observed in passive mode. As the vehicle behind changes, the next is observed and within a short period of time the behaviour of several drivers can be examined, without the observed driver being aware. The paper presents the experiment by describing the road context, aims and experimental procedure. Statistics and initial insights are also presented based on the large amount of data collected (more than 8000 km of observed trajectories and 120 hours of driving in active mode). As an example of how to use the data directly, apart from calibration of driving behaviour models, indexes based on aggregate measures of safety are computed, presented and discussed.

ABSTRACT Several studies have developed operating speed prediction models. Most of the models are based on spot speed data, collected by radar guns, pavements sensors and similar mechanisms. Unfortunately, these data collecting methods force the users to assume some invalid assumptions in driver behaviour modeling: constant operating speed throughout the horizontal curves and occurrence of acceleration and deceleration only on tangents. In this study an instrumented vehicle with a GPS continuous speed tracking was used to analyze driver’s behaviour in terms of speed choice and deceleration/acceleration performances and to develop operating speed prediction models. The data used in the study were from a field experiment conducted in Italy on the rural motorway A16 (Naples-Avellino). Models were developed to predict operating speed in curves and in tangents, deceleration and acceleration rates to be used in the operating speed profiles, starting and ending points of constant operating speed in a curve, 85th percentile of the deceleration and acceleration rates of the individual drivers, and 85th percentile of the individual drivers’ maximum speed reduction in the tangent-to-curve transition.The study results show that (a) drivers’ speed was not constant along the curves, (b) the individual drivers’ maximum speed reduction was greater than the operating speed difference in the tangent-to-curve transition, and (c) deceleration and acceleration rates experienced by the individual drivers were greater than deceleration and acceleration rates used to draw the operating speed profiles.

ABSTRACT In the field of Intelligent Transportation Systems (ITS), one of the most promising sub-functions is that of Advanced Driver Assistance Systems (ADAS). Development of an effective ADAS, and one that is able to gain drivers' acceptance, hinges on the development of a human-like car-following model, and this is particularly important in order to ensure the driver is always 'in the (vehicle control) loop' and is able to recover control safely in any situation where the ADAS may release control. One of the most commonly used models of car-following is that of the Action Point (AP) (psychophysical) paradigm. However, while this is widely used in both micro-simulation models and behavioural research, the approach is not without its weaknesses. One of these, the potential redundancy of some of the identified APs, is examined in this paper and its basic structure validated using microscopic driving behaviour collected on thirteen subjects in Italy. Another weakness in practical application of the Action Point theory is the identification of appropriate thresholds, accounting for the perception, reaction and adjustment of relative speed (or spacing) from the leading vehicle. This article shows that this identification is problematic if the Action Point paradigm is analysed in a traditional way (car-following spirals), while it is easier if the phenomenon is analysed in terms of car-following 'waves', related to Time To Collision (TTC) or the inverse of TTC. Within this new interpretative framework, the observed action points can be observed to follow a characteristically linear pattern. The identification of the most significant variables to be taken into account, and their characterisation by means of a simple linear pattern, allows for the formulation of more efficient real-time applications, thereby contributing to the development and diffusion of emerging on-board technologies in the field of vehicle control and driver's assistance.

Abstract DRIVE IN2 is an automotive research project within the field of Intelligent Transportation Systems, especially Advanced Driving Assistance Systems (ADAS). The project originates from the idea that the development of new ADAS and evaluation of their effect have to take drivers into account, as well as their behavior while driving: the benefits of adopting new in-vehicle technologies depend also on their adoption and usage by drivers. To this aim, the project develops a Driver-In-the-Loop framework to position observation of ...

Abstract Identification of driving behavior is a crucial task in several Intelligent Transportation Systems applications, both to increase safety and assist drivers. Here we identify driving behaviors by means of an analytical model. In order to estimate the model parameters, data are collected with an instrumented vehicle. The paper presents the model, the procedure for the estimation of the parameters and the results of the proposed framework with respect to a pilot experiment to assess the feasibility and potential of the approach. Some practical ...

Abstract Adaptive Cruise Control systems have been developed and introduced into the consumer market for over a decade. Among these systems, fully-adaptive ones are required to adapt their behaviour not only to traffic conditions but also to drivers' preferences and attitudes, as well as to the way such preferences change for the same driver in different driving sessions. This would ideally lead towards a system where an on-board electronic control unit can be asked by the driver to calibrate its own parameters while he/she ...

Abstract The study of travellers behaviour in ATIS (Advanced Travellers Information Systems) contexts is a crucial task in order to properly simulate phenomena like as the compliance with the information, the route choice in presence of information, etc. A correct simulation of these phenomena is crucial in appraising ATIS options. Observations of travellers behaviours are often made with reference to simulated environments. SP (Stated Preferences) techniques are generally applied. In literature two main types of tools for SP ...

Abstract: The study of travellers behaviour in ATIS (Advanced Travellers Information Systems) contexts is a crucial task in order to properly simulate phenomena like as the compliance with the information, the route choice in presence of information, etc. A correct simulation of these phenomena is crucial in appraising ATIS options. Observations of travellers behaviours are often made with reference to simulated environments. SP (Stated Preferences) techniques are generally applied. In literature two main types of tools for SP ...