Ioanna Spyropoulou

ITS Solutions and Accident Risks: Prospective and Limitations

Abstract This article investigates the prospective and limitations in the application of potential intelligent transport system (ITS) functions to reduce accident risks, using a cause‐treatment relationship. The main causes of road accidents are described and appropriate ITS solutions (including advanced driver assistance systems and advanced traveller information systems) are presented as countermeasures. Anticipated impacts are discussed and indicate that several ITS have the potential of improving road safety and addressing specific accident causes. However, attention is required on particular aspects of their implementation as they may trigger adverse effects by imposing behavioural adaptation risks, and overestimation and over‐reliance on system capabilities. Further, user acceptability and strategic implementation issues are paramount to the successful introduction of these systems.

Mobility Patterns of Motorcycle and Moped Riders in Greece

This paper investigates the mobility patterns of powered two-wheeler riders in comparison with those of passenger car drivers in Greece, a country in which an increased rate of two-wheeler ownership and related traffic is observed. A nationwide travel survey targeted at active two-wheeler and passenger car drivers was carried out for that purpose. The results of the survey were exploited in two ways. First, the use of the vehicle types examined in Greece was investigated in relation to driver characteristics by calculation of the respective sample distributions. The results demonstrated a clear difference between vehicle ownership rates and vehicle use rates by vehicle type. Moreover, the mobility patterns of each vehicle type were compared on the basis of the average yearly mileage traveled in relation to driver (age, gender, experience), vehicle (engine size), type of trip (weekday or weekend), and road environment (area type, lighting conditions, road type). The findings indicated that driver gender, age, and experience appeared to be a stronger determinant of mobility patterns than vehicle type. But different mobility patterns among vehicle types in different road environments were identified; this suggests that mopeds and motorcycles are preferred for particular types of trips (e.g., traveling in residential areas and weekdays during the daytime), whereas passenger cars may be used in all cases.

Cellular Automata Model Properties: Representation of Saturation Flow

The current study investigates the way in which the saturation flow of a traffic lane is representedthrough widely used cellular automata models. In particular, following a literature search specific cellular automata models that have been developed to simulate mainly urban traffic are selected for this study. The values of the saturation flow as these are produced via model simulations with the modification of relevant model parameters including maximum desired speed and probability are defined through appropriate statistical values.

Parameters Affecting Professional Driver Response to VMS Messages

Professional drivers, in this case truck drivers and taxi drivers, exhibit distinct behavioural characteristics concerning route choice compared to the rest of the driving population. At the same time the number of such drivers in urban areas is considerable and their impact on traffic conditions substantial. This work attempts to identify parameters that affect professional driver response to traffic-related information transmitted via Variable Message Signs (VMS), under incident occurrence. A stated preference questionnaire survey is designed and distributed to about 100 taxi drivers and 100 truck drivers, operating in the city of Athens. Ordered probit models with random effects that highlight the contributory factors of driver response, concerning route choice, are specified and estimated. Message characteristics, in particular information on incident impact (delay) and provision of an alternative route, influence driver response, whereas incident cause does not. Specific trip and driver characteristics are also identified as contributory factors.

Models on the Road

In this chapter, the application of macro and micro traffic simulation modelling for the needs of road safety assessment and planning is dealt. The overall concept of traffic simulation modelling regarding safety is presented, together with a series of macro and micro simulation models (namely RuTSim, S-Paramics, SATURN and VISSIM) that are widely used and have been specifically applied for the needs of IN-SAFETY project. ITS and ADAS related scenarios defined within IN-SAFETY, aiming to enhance the road safety level, have been tested through specially developed applications of these models and their results indicate the influence of the use of such technologies, as well as the effectiveness of the selected models in simulating and evaluating their effects. Future enhancement in the models will provide the possibility of further using them in the context of road safety and the involvement of innovative technologies.