Traffic oscillation is a very important phenomenon in traffic flow studies and its characteristics are usually used to validate the developed traffic flow models and theories. In this paper, we ...firstly conduct an empirical study based on floating car data, focusing on the characteristic of traffic oscillations in terms of the overall amplitude and the spectrum of speed/acceleration as well as the relation between the characteristic quantities. It is found that the amplitude of both speed oscillations and acceleration oscillations grows with the increase of traffic speed. The spectrum analysis shows that the most energy would concentrate on a narrower band with the increase of standard deviation of speed/acceleration, and the periodicity in the speed oscillation is more salient than that in the corresponding acceleration oscillation. Then, three typical car-following models are tested: one is the deterministic model, while the other two are the stochastic models with different mechanisms of stochasticity. The simulation results indicate that the two stochastic models outperform the deterministic model in reproducing the observed oscillation characteristics qualitatively and quantitatively.
•The collected floating car data with high accuracy provides pinpoint evidence for the characteristic of traffic oscillations.•The IDM fails to reproduce qualitatively observed oscillations, while the 2D-IDM and SSAM could.•The formation and propagation of oscillations might be due to the stochasticity in car following.
•The HySolarKit may be a promising technology.•The intention to adopt the kit and the choice to install it may be effectively modelled through the random utility theory.•Market segments to be ...captured by such technology mainly consist in male and younger users.•Concern for environment and design affect intention to adopt but do not affect installation propensity.•The probability of installing the kit is greatly affected by the installation costs and the weekly mileage driven.
Despite the recent commercial success of hybrid, plug-in hybrid and electric vehicles their market share is still insufficient to produce either a significant impact on energy consumption on a global basis or a profitable automotive segment. In this context, the possibility of upgrading conventional vehicles to hybrid electric vehicles is gaining increasing interest.
To this aim this paper investigated and modelled the intention to install an after-market hybridization solar-kit (HySolarKit) in order to ascertain the main behavioural determinants of the choice process and set up an operational model with which to estimate the market potential of such technology. In particular, two behavioural stages of the choice process were analysed and modelled: (i) the intention to adopt the HySolarKit; (ii) the choice to install the HySolarKit. Both issues were addressed through ad hoc stated preference surveys carried out in two different Italian cities, and through the specification and the calibration of discrete choice models based on the behavioural paradigm of random utility theory. Different modelling solutions (homoscedastic and heteroscedastic) were compared in terms of goodness-of-fit and sensitivity to level-of-service attributes. The results showed the technological potential of the HySolarKit, and that both behavioural stages may be effectively modelled through random utility theory. Estimation results allowed an interpretation of the main determinants of the investigated phenomena, making it possible to quantify the potential effects and the concerns towards such a green solution, and making it possible to draw up operative marketing strategies. In particular, the intention to adopt the kit mainly depends on socio-economic factors as well as activity-related and attitudinal attributes, whereas the probability of installing the kit is greatly affected, to the same extent, by installation cost, the charging cost and the weekly mileage driven.
Several systems have been proposed in recent years for Advanced Traveler Information Systems (ATIS), ranging from personal (mobile application, on-board) navigation to VMS (Variable Message Signs). ...All these applications are essentially aimed at assisting the travelers in their travel choices by means of technologically dispatched information about traffic network structure and traffic conditions. It is well known that in ATIS applications one of the key issues to be addressed concerns the accuracy of the dispatched information, here intended as the ability of the system in supplying information that can be verified by the travelers to be correct (affected by a small error). This paper aims at proposing some analytical models able to simulate the effects of the (in)accuracy on travelers' compliance with information.
•The stage sequence optimisation may significantly affect the network signal setting design.•The multi-criteria optimisation is a suitable/effective strategy for a single junction.•The proposed ...CT&PDM overcomes the limitations of either models.
This paper aims to investigate the application of meta-heuristic optimisation methods to Network Signal Setting Design. The adopted approaches are (i) three step optimisation, in which first the stage matrix (stage composition and sequence), the green timings at each single junction are optimised, then the node offsets are computed in three successive steps; (ii) two step optimisation, in which the stage matrix is defined at a first step, then the green timings and the node offsets are computed at a second step. In both approaches the stage matrix optimisation is carried out through explicit complete enumeration.
In the first approach multi-criteria optimisation is followed for single junction signal setting design (green timings), whilst the coordination (node offsets) is approached through mono-criterion optimisation, as well as for the synchronisation (green timings and offsets) in the second approach.
A new traffic flow model mixing CTM and PDM has been applied. This model allows to explicitly represent horizontal queuing phenomena as well as dispersion along a link. Some meta-heuristic algorithms (i.e. Genetic Algorithms, Hill Climbing and Simulated Annealing) are investigated in order to solve the two problems.
The proposed strategies are applied to two different layouts (a two junction arterial vs. a four junction network) and their effectiveness is evaluated by comparing the obtained results with those from benchmark approaches implementing mono-criterion optimisation only.
Recent developments in the ITS field are orienting the research towards new paradigms or on the development of new traffic models based on existing ones. The main focus of this paper regards the ...development of a hybrid traffic model using existing models in the literature as a base, being able to support the modelling and control of automatic and connected vehicles. This paper proposes an innovative hybrid model tested in a close loop to verify its continuity and on an arc with a traffic light downstream to analyse the creation and discharge of queues. It also provides traffic indicators to compare these layouts modelled with the Hybrid model with respect to an application of a basic Cell Transmission Model and Cellular Automata model. Results provide three main contributions: i) the local consistency is verified; ii) it is suitable for applications of traffic control strategies; iii) it is reliable in terms of reality reproduction.
The possibility of upgrading conventional vehicles to hybrid electric vehicles has recently gained considerable interest. Among the diverse options for hybridization, researchers of the Energy and ...Propulsion Laboratory at the University of Salerno (Italy) have patented a system based on the electrification of the rear wheels in front-wheel-drive vehicles by adopting in-wheel motors and adding a lithium-ion battery, which is rechargeable via plug-in and solar mode. The technology integrates various components, in-vehicle Intelligent Transportation Systems and advanced on-line management algorithms. With respect to the proposed technological context, this paper uses a real case study to investigate the potential market penetration, the achievable environmental benefits and relevant policy issues. To this aim, the paper first analyses the main behavioral determinants that may affect users' perception of this new technology, then specifies and calibrates an installation choice model, and finally develops bottom-up methodology to estimate the environmental benefits to be obtained from different commercialization scenarios. The proposed methodology was applied to the city of Salerno and the achievable benefits were compared to those obtainable through the implementation of traditional transport policies.
In this paper carsharing behavior was investigated with regard to a different and little investigated aspect of users’ behavior: modeling the propensity in adhering to a carsharing system. The ...propensity was modeled within the random utility framework through starting from a stated preferences survey. The main focus was on the investigation and estimation of a set of attributes able to interpret and measure the propensity. In particular, together with socio-economic and activity related attributes, the satisfaction variable (expected maximum utility) was tested in order to interpret the interest towards carsharing in light of the level of service supplied by the other transport modes and of the users’ socio-economic and activity-based characteristics. The satisfaction variable was specifically calibrated on actual mode choice behavior starting from revealed preferences data.
Purpose
This paper analyses travellers’ behaviour with respect to route choice in a context where an Advanced Traveller Information System (ATIS) is in place. ATIS are important applications in the ...field of intelligent transportation systems (ITS). However, the practical impact of ATIS is still a matter for debate, and identification of expected route choice behaviour under ATIS is one of the main ways to assess their practical importance.
Methods
Travellers’ choices are frequently explored by means of stated preference (SP) approaches. In this paper we discuss some issues to be addressed when an SP survey is carried out, with particular reference to cases where a repeated choice approach is employed in the survey.
Results
Our analysis concerns an application of the SP approach in a pilot study aimed at identifying the effects of ATIS accuracy on travellers’ compliance with information.
Conclusions
This paper aims to make two major contributions. First of all, empirical analyses based on proper indicators and statistical tests are suggested in order to evaluate how the collected data have to be handled in order to eliminate transient route-choice observations. These are due to the warm-up phase inherently associated with the survey method adopted, dealing with repeated choices. Secondly, we analyse (stationary) route choice in order to assess the effects of information reliability (and the kind of information) on both route choice and compliance.
The paper focuses on the analysis of the traveler's behavior in a route choice context in presence of information. In general, in case of choice contexts where the uncertainty is due to the actual ...travel times variances and/or the information accuracy, travelers' reaction, usually modeled by considering the utility maximization paradigm, may be affected by the risk perception. However, depending on the considered tool for collecting data (driving vs. web-based simulator) different behaviors (such as risk aversion) may be observed. This paper aims to applying the Cumulative Prospect theory in order to model travelers' behavior in a risky route choice context using data collected by different tools. In particular, in this paper data collected by (static) driving simulator and (web-based) travel simulator are compared by aggregated analysis. Finally, the results of the modelling approach are shown in order to properly evaluate how the simulation environment may affect the travelers' risk perception by introducing a bias in alternative choice.
PDF
