An assessment of VMS-rerouting and traffic signal planning with emission objectives in an urban network — A case study for the city of Graz

This paper discusses a case study evaluating the potential impact of ITS traffic management on CO 2 and Black carbon tailpipe emissions. Results are based on extensive microsimulations performed using a calibrated VISSIM model in combination with the AIRE model for calculating the tailpipe emissions from simulated vehicle trajectories. The ITS traffic management options hereby consist of easily implementable actions such as the usage of a variable message sign (VMS) or the setting of fixed time signal plans. Our simulations show that in the current case shifting 5% of vehicles from one route to another one leads to an improvement in terms of emissions only if the VMS is complemented with an adaptation of the signal programs, while the VMS sign or the change of the signal plans alone do not yield benefits. This shows that it is not sufficient to evaluate single actions in a ceteris paribus analysis, but their joint network effects need to be taken into account

Journey decision making: the influence on drivers of dynamic information presented on variable message signs

In many highways environments electronic media such as variable message signs are increasingly being used to provide drivers with up-to-date dynamic information in order to influence driving decision making during journeys. These decisions may be associated with strategic choices, such as route selection, or tactical decisions, such as driving at a certain speed, or altering driving style. This paper presents a study that used two methods - a scenario approach and a medium-fidelity driving simulator. Data from both methods are presented here and include decision making and driving performance data. These data provide an insight into the role of information and other contextual influences in decision making in the driving context specifically, but also has useful implications for the way in which information should be designed in other decision making contexts, such as travel using public transport, or supporting real-time complex control operations. The use of multiple data collection approaches also enabled data comparisons to be made, thus improving overall confidence in conclusions. The paper highlights the role of familiarity with information wording and context, level of detail, interpreted meaning, previous experience and contextual cues on trust in information and consequently behaviour in response to the information presented

Development of a Latent Variable Model to Capture the Impact of Risk Aversion on Travelers' Switching Behavior

AbstractAdvanced Traveler Information Systems (ATIS) are becoming increasingly available throughout the world. While the impact of the provided information on the switching behavior has been investigated in the past, an area of research that is less well understood relates to the effect of the travelers' risk aversion (or risk-seeking) in their travel behavior. The objective of this research is to examine the impact of information acquisition on travelers' switching travel behavior and to identify and quantify the role of attitudes and perceptions on switching behavior. A combined choice and latent variable model has been developed, in which the individual traveler's risk aversion has been modeled as a latent variable. The model has been estimated using data collected through travel diaries in the Puget Sound Region (PSRC) in 2000. As expected, travelers in general tend to maintain their habitual travel pattern. However, specific travel information-such as that regarding an incident or road closure-influences behavioral switches such as departure time change and route change

Intelligent transport systems harmonisation assessment: use case of some Spanish intelligent transport systems services

From the 1980s, new telematic technologies have meant a great evolution in several areas. In the transportation domain, their use has implied the development and implementation of several intelligent transport systems (ITS). However, these deployments were done in an isolated way. Traffic managers, public and private organisations, stakeholders and others have implemented ITS without much perspective, that is, without providing ITS as services for end users. In the last few years, several European Union (EU) funded projects have been dealing with the development of harmonised ITS services. For example, the EasyWay Project is involving most of the European countries (EU member states and others) to deploy harmonised ITS services taking into account the European citizen as the final target. In this study, an introduction of the EasyWay project is made, including the ITS concept services and the deployment guidelines for harmonisation. In November 2012, EasyWay presented a new version of DGs, which were approved with minor editorial changes. An overview on these DGs for the ITS services is presented and two real Spanish road traffic ITS services are analysed

Effect of design factors on drivers’ understanding of variable message signs locating traffic events

Background: This article addresses how to combine three elements (a pictogram, an arrow, a city) in a variable message sign (VMS) to locate temporary events (e.g., “congestion before Milan”). We adopted the G1c stack model as a design template, an Advanced Directional Sign (ADS) recommended by the 1968 Convention to locate cities, which can be easily adapted to modern VMS. However, as most of the VMS in operation are not full-matrix, we have also adapted this design to more restrictive display conditions. This adaptation critically concerned the arrow function on the message that either points up broadly (generically, as in G1c) or connects with the city more specifically (explicit). Although G1c reads top-down like a verbal text, previous studies indicated drivers’ preference for bottom-up landmark order in VMS, so both ordering criteria were compared in the present study. Methods: The experiment involved 99 people (70 drivers and 29 drivers in training). Participants were informed that they would see various VMS reporting certain events (e.g., congestion) related to one of four cities along the road. Their task was to identify the event location (before, after the city) after seeing blocks of two consecutive messages (first a complementary message, then the target message), limiting their response to the content of the second message. Three design-focused factors were tested: typographical alignment (left or centre), landmark order (bottom-up or top-down), and arrow function (explicit or generic). The rate of correct location answers was the dependent variable. Results: Results revealed that comprehension varied greatly depending on the arrow’s function and the placing of elements. In the explicit-arrow messages, comprehension was good both in the Top-down and Bottom-up conditions, but in the generic-arrow messages, only in the Bottom-up condition was comprehension good. Likewise, understanding was better in the Before condition than in the After condition in all combinations of Landmark order and Arrow function conditions. In general, left alignment of the central column elements of the VMS improved comprehension respective to centred alignment. Finally, the complementary message factor had an effect under certain circumstances. Practical implications: The messages displaying a generic arrow (following the G1c model) were better understood when the landmarks were ordered bottom-up, not top-down. In addition, explicit-arrow messages were better understood per se (in the absence of a complementary message) than generic-arrow messages. Overall, this work suggests that improving our understanding of how thought processes and design features relate to each other can contribute to safer driving nationally and internationally

Monetising human impacts. CLeMM: Customer Led Monetising Method

Executive Summary: This study has developed a Customer Led Monetising Method (CLeMM) to assess the monetary value of the human impacts of Highways England's operational services. CLeMM is simple in concept, easy to use and adaptable to a wide variety of situations enabling Highways England to use it in surveys, focus groups and other customer consultations for the widest range of stakeholders. The method for using CLeMM is described in the CLeMM Guide

Effects of Weather Related Safety Messages on the Motorway Traffic Parameters

Intelligent transport systems have a huge importance during adverse weather conditions. These systems call the drivers’ attention to possible dangers by the use of variable message signs installed along the motorways. Several researchers have dealt with the connection of weather and traffic safety in the last decades, but they have not investigated the effects of weather related messages. This paper examines the impact of weather-related warning messages on traffic in adverse weather circumstances on the Hungarian motorways. Three independent databases were analyzed in order to compare the speed-reducing effect of specific signs during different weather events and precipitate intensities