European Transport / Trasporti Europei (2013) 53

The object of the paper is to investigate the effect of signal synchronization on the traffic flow patterns on the network and validate results of synchronization problem in signal setting design. A platoon based traffic model is applied to solve both one-way and two-way synchronization problems in under-saturated conditions. Assessment of results through dynamic traffic assignment model shows that solution found is rather robust and, if more traffic is attracted by the improved arterial performance, larger benefits can be achieved on the whole network. A specific analysis has been conducted to point out the representation of queue propagation and the gridlock phenomenon.

Customer satisfaction analyses are deeply based on customers’ judgments and as consequence, they can be characterized by a certain degree of uncertainty generally ascribed to coexistence of three relevant aspects: vagueness, imprecision and subjectivity. In the present paper, a methodology able to handle such uncertainty, based on the ServQual discrepancy paradigm and that uses in combined manner the AHP method and the Fuzzy Sets Theory is proposed in order to overcome limitations of the traditional service evaluation approaches. Subsequently, by considering the Italian public transit service sector, a service quality analysis is conducted and the overall transit service quality structure is described. Finally, by using the developed methodology, the evaluation of customer satisfaction for the public urban transit service provided in the city of Palermo (Italy) is performed, and the prioritizing of its critical to quality service attributes is carried out. The obtained results show that only few service attributes play an important role in performing a quality transit service.

The study presented here aims to validate some operating speed prediction models calibrated on two-lane rural roads by using speed data collected in Northern and Southern Italy. Operating speed is defined as the speed at which drivers of passenger cars travel on a dry road in free flow conditions during daylight hours and it is calculated using a specific percentile of speed distribution, typically the 85th. Speed measurements were carried out by using laser detectors in connection with previous environmental and traffic conditions. The study is addressed to emphasize the reliability and easy application of one predictive speed model working both on tangent segments and on circular curves. The calibration phase involved roads in the Northern Italy, while the validation phase involved roads in the Southern Italy. Three models were validated applying them on eight two-lane rural roads falling within the road network of the Province of Salerno with features that reflect those adopted in the calibration phase; the selected models to be validated present the simplest analytical structure for type and number of explanatory variables and for the performance diagram shape of the operating speed values. The validation procedure was to estimate some synthetic statistical parameters as mean absolute deviation, mean squared error and coefficient of variation. The results allow in a simple way to trace continuous operating speed profiles on two-lane rural roads and to carry out safety analyses on the horizontal alignment.

The study presented in this paper uses Stated Preferences (SP) data on mode choice collected as part of a recent survey on long distance travel u n dertaken in three European countries. The purpose of this article is twofold. It aims at exploring the impacts of the choic e of mixing probability distri butions while accounting for unobserved taste heter ogeneity and it aims at focusing on the derived estimation of the distribu tions of values of travel time savings (VTTS). We compare eleven distributions, each having particular properties in terms of domain, location, scale, and shape. Due to the repetiti ve nature of the SP experiments, we estimate mixtures of Multinomial Logit (MNL) models for panel data. The results show that the mixing distributions differ from one country to another, suggesting existence of European disparities as it regards long - dista nce mode choice. The results also show that long - distance travellers pay a lot more attention to access and egress travel times to and from the main mode than to total travel time with the main mode.

This study considers the problem of estimating the reduction of roundabout entry capacity caused by pedestrian zebra crossings. An empirical procedure is developed on the basis of field observations collected at an urban four-leg roundabout located in Padova (Italy). The disturbance caused by pedestrians to approaching traffic is measured using crosswalk occupancy times, rather than pedestrian volumes like in previous studies. The proposed method leads to the determination of a capacity reduction index, which can be applied in operational analyses to obtain realistic estimates of roundabout entry capacities taking into account the impact of pedestrian crossings. Also, the possible effect of introducing pedestrian-actuated signal control on zebra crossings is evaluated, using simulation, with reference to alternative pedestrian volume and signal timing scenarios.

Car lane-changing behaviour has been well investigated at merging locations or weaving sections where the lane-changes are usually due to different origin-destination trip purposes. However, the lane-changing behaviour under the effects of bus priority-lanes in urban streets has not been received much attention. This kind of behaviour is found to initially depend on the existence of oncoming buses in priority-lanes in urban streets. In this paper, a car lane-changing model under bus priority-lane effects in urban streets is proposed. This model comprises three steps: looking-back threshold determination, gap acceptance model and execution model. The model’s parameters are estimated jointly by using the Maximum Likelihood Method. The research results show that the car lane-changing behaviour under bus-priority-lane effects in urban streets is considered compulsory behaviour. The behaviour has specific characteristics with smaller critical gaps compared with those at other normal lane cases and can be modelled by the proposed model.

Estimation of transportation network capacity is important in analysing network performance. In the existing literature, the capacity of a network is defined in conditional terms as a theoretical construct called “reserve capacity”. This may be limited because, when considering local land-use development, the hypothetical uniform increase in O-D flows is not always realistic. This paper, introducing the concept of “capacity function”, proposes a generalized concept of road network capacity which does not require information on either current O-D demand or the corresponding growth trend. Attention focuses on deterministic and stationary situations in which only one path is available for each O-D pair. Some examples regarding simple study cases demonstrate the capacity of this approach to solve problems and, consequently, to contribute to the analysis of network performance.

The pedestrian walking data collected at nineteen locations in five cities of India are analyzed in this paper. Pedestrian facilities are classified based on their width as sidewalk, wide-sidewalk and precincts. The analysis indicates that the pedestrian free flow speed is high on sidewalks (1.576 m/s) and low on precincts (1.340 m/s). The increase in width of the facility resulted in increased space available to a pedestrian, but reduced maximum flow rate and optimum density. It is found that the relationship between speed and density follows Underwood (exponential) model on sidewalk of varying widths and Greenshield’s (linear) model on a non-exclusive facility. Bi-directional flow on a facility affects the free flow speed and space available to the pedestrian adversely at high density. Squeezing effect at the centre and follow the predecessor near sides is observed under heavy bidirectional flow. The presence of a bottleneck reduces the free flow speed and maximum flow substantially. Pedestrians moved in layers at high density. Maximum flow rate is observed to be higher on the carriageway (2.067 ped/s) as compared to an exclusive pedestrian facility (1.493 ped/s).

The adoption Eurovignette Directive 2011 has reinforced the discussion on the highly contested ‘polluter pays principle’. This paper presents the course of the legislative procedure ab ovo ad malum and pinpoints instances of the legislator negotiating beyond the frame of publicity provided by the Treaties. At the same time it provides for a critical analysis of the novelties in the field of charging of heavy goods vehicles on the EU’s roads and reveals that the Council is the true decision-maker in this very legislative project, whereas the Parliament, and even more the Commission, were less able to push through their views. The new Directive has brought some progress in the development of European transport policy, but it could not meet the high expectations this legislative project was accompanied by from its very beginning.

Trip making behavior of people is becoming complex day by day due to their modern and hectic life style. This exhibits that a better understanding of trip chain decision making is necessary to transportation researchers and policy makers. Hence, this paper explores trip chaining behavior of Mumbai Metropolitan Region (MMR) residents using the activity-travel survey conducted by the authors in 2011. This paper proposes a typology of trip chains based on the structure of trips and activity purpose. Further, this study develops an empirical framework to examine the effect of household and individual socioeconomic characteristics, and travel choices on individual trip chain making behavior. In addition to the descriptive analysis, a nested logit model is proposed for further understanding of the concept. Model estimation results shows that, the identified variables have significant explanatory power in the decisions relating to the trip chain choice. This study provides promising insights on trip chaining behavior of the people in developing countries and it also extends the need to incorporate trip chaining behavior in existing travel demand forecasting models.