Showing papers in "European Transport Research Review in 2018"

Simulation of B2C e-commerce distribution in Antwerp using cargo bikes and delivery points

Abstract: The growth of e-commerce is accompanied by an increasing distribution of parcels in cities resulting in externalities like traffic congestion or emissions. As a consequence, different delivery concepts like bike deliveries or delivery points have been suggested. Naturally, companies will only accept these changes, if they do not result in higher costs. However, it is difficult to predict the impact of a certain delivery concept in a certain city. This leads to the research question, how different delivery scenarios for a certain area can be assessed and compared, especially if some of them have not been implemented. Using a case study, we demonstrate how the effects of different delivery concepts can be quantified with the help of a simulation study. We take care to accurately model the delivery processes and utilise a real-world dataset and realistic cost values. On the basis of these inputs, we simulate and analyse the current state-of-the-practice in the distribution of e-commerce goods in Antwerp and compare it to possible `what-if’ scenarios. The results highlight that the investigated delivery concepts can benefit either the companies or the quality of life in the city. Operational costs of companies can be reduced by stimulating customer self-pick-up, while externalities decrease with the implementation of a cargo bike distribution system. We demonstrate that both operational and external costs can be minimised, if involved stakeholders from industry and the public look for sustainable delivery solution jointly.

Analysis and modelling of performances of the HL (Hyperloop) transport system

Abstract: Hyperloop (HL) is presented as an efficient alternative of HSR (High Speed Rail) and APT (Air Passenger Transport) systems for long-distance passenger transport. This paper explores the performances of HL and compares these performances to HSR and APT. The following performances of the HL system are analytically modeled and compared to HSR and APT: (i) operational performance; (ii) financial performance; (iii) social/environmental performance. The main operational result is that the capacity of HL is low which implies a low utilization of the infrastructure. Because the infrastructure costs dominate the total costs, the costs per passenger km are high compared to those for HSR and APT. The HL performs very well regarding the social/environmental aspects because of low energy use, no GHG emissions and hardly any noise. The safety performance needs further consideration. The HL system is promising for relieving the environmental pressure of long-distance travelling, but has disadvantages regarding the operational and financial performances.

Overview of traffic incident duration analysis and prediction

Abstract: Non-recurrent congestion caused by traffic incident is difficult to predict but should be dealt with in a timely and effective manner to reduce its influence on road capacity reduction and enormous travel time loss. Influence factor analysis and reasonable prediction of traffic incident duration are important in traffic incident management to predict incident impacts and aid in the implementation of appropriate traffic operation strategies. The objective of this study is to conduct a thorough review and discusses the research evolution, mainly including the different phases of incident duration, data resources, and the various methods that are applied in the traffic incident duration influence factor analysis and duration time prediction. In order to achieve the goal of this study, we presented a systematic review of traffic incident duration time estimation and prediction methods developed based on various data resource, methodologies etc. based on the previous studies, we analyse (i) Data resources and characteristics: different traffic incident time phases, data set size, incident types, duration time distribution, available data resources, significant influence factors and unobserved heterogeneity and randomness, (ii) traffic incident duration analysis methods, mainly including hazard-based duration model and regression and statistical tests, (iii) traffic incident duration prediction methods and evaluation of prediction accuracy. After a comprehensive review of literature, this study identifies and analyses future challenges and what can be achieved in the future to estimate and predict the traffic incident duration time.

A macroscopic traffic model for traffic flow harmonization

Abstract: Traffic flow will harmonize to forward conditions. The time and distance required for harmonization can have a significant effect on the traffic density behavior. The flow can evolve into clusters of vehicles or become uniform depending on parameters such as safe time headway and safe distance headway. In this paper, a new model is presented to provide a realistic characterization of traffic behavior during the harmonization period. Results are presented for a discontinuous density distribution on a circular road which shows that this model produces more realistic traffic behavior than other models in the literature.

Analyzing urban traffic demand distribution and the correlation between traffic flow and the built environment based on detector data and POIs

Abstract: This paper aims to determine the urban traffic flow spatiotemporal characteristics and correlation with the built environment using SCATS (Sydney Coordinated Adaptive Traffic System) and POIs (Point of Interests) data of Shenyang, China. A standard analysis framework based on these data is proposed in the paper. The study analyzes the traffic volume spatiotemporal distributions and built environment influence factors determined by the geographical detector. An improved gravity model using simple structural parameters (lanes number and road length) is proposed to estimate the traffic flows of day and peak hour scales for specific flow ranges. The results show that the peak hours of different intersections and roads are heterogeneous and reveal trip time flexibility. The correlation between peak hour flows and day flows is significant in the multidimensional analysis. Based on the investigation of lanes, more interesting conclusions are found. In this case, when the numbers of lanes of intersections and roads are more than 14 and 4 respectively, the lane resources are wasted to a great extent. There is also a certain correlation between these factors. Proposed gravity model establishes the connection between structure and function of urban roads. Flexible work time and places will be effective methods to reduce traffic congestion. The day flows could be estimated via a traffic survey on peak hour flows, especially in developing cities. The traffic flow mainly concentrates in a relatively small part of city roads. The maximum service traffic volumes exhibit segmentation, we should reconsider the maximum optimal lanes number of intersections and roads under better performance and utilization rate of the network. The effect of lanes number on the service traffic volumes is found to be more significant compared with the other factors. Our conclusions will be helpful for policy-makers and sustainable urban planning.

Headway distribution models of two-lane roads under mixed traffic conditions: a case study from India

Abstract: The time headway of vehicles is of fundamental importance in traffic engineering applications like capacity, level-of-service and safety studies. Further, the performance of traffic simulation depends on inputs into the simulation process and ‘accurate vehicle generation’ is critical in this context. Thus, it is important to define headway distribution pattern for the purpose of analyzing traffic and subsequently, taking infrastructure related decisions. In so far, majority of the researches on this subject are based on homogeneous traffic and effects of mixed traffic especially on two-lane roads are yet to be culminated. The present study, thus, aimed at investigating headway distributions on such roads under mixed traffic situation. Field study was conducted on two-lane highways in India that exhibits heterogeneity in its traffic composition. Contestant headway distribution models were evaluated and four distribution functions namely, log-logistic, lognormal, Pearson 5 and Pearson 6 were considered while modeling the headway data. The appropriate models were selected using a methodology based on K-S test and subsequent field validation. Log-logistic distribution was found appropriate at moderate flow whereas, at congested state of flow it was Pearson 5. However, at unstable flow nearing capacity, both, following and non-following components of headways were observed to follow different distributional characteristics. Nomographs are developed for calculating the headway probabilities at different flow levels considering the appropriate distribution models. ‘Probability of headway less than‘t’s’ increases with the flow rate and rate of such increase is considerably high for headways 7.5 s or more. This attributes to the fact that at heavy flow more vehicles are entrapped inside platoons and they move in following with shorter headways. Further, a comparison was made between the headway probabilities obtained in the current study and road segments that exhibit more or less homogeneous traffic. It was found that at moderate flow level proportion of shorter headways are considerably high under mixed traffic. The present paper demonstrates the effect of mixed traffic on distribution of time headways of two-lane roads. Presence of slower vehicles in such traffic leads to frequent formation of platoons, thereby, increases the risk taking behavior of drivers’ while overtaking. As a result, proportion of shorter headways increases resulting in highly skewed observations. Thus, the study proposed Log-logistic distribution under medium flow since it can model events which have ‘increased initial rate’ and Pearson 5 under heavy flow to model ‘highly skewed data’. The model outputs were accordingly compared with other studies and were found to explain the mixed traffic characteristics satisfactorily. The present study, thus, creates a starting point of further initiatives aimed at establishing a robust method of modeling headways on two-lane roads with mixed traffic.

An international review of challenges and opportunities in development and use of crash prediction models

Abstract: Over the past 10 years, building on road infrastructure data, crash prediction models (CPMs) have become fundamental scientific tools for road safety management. However, there is a gap between state-of-the-art and state-of-the-practice, with the practical application lagging behind scientific progress. This motivated a review of international experience with CPMs from perspectives of application by practitioners and development by researchers. The objective of the paper is to improve practitioner understanding of modelling road safety performance using CPMs for crash frequency estimation, leading to their greater uptake in improving road safety. In short, why and how should road safety practitioners consider CPMs? Both scientific and practice-oriented literature was retrieved, using academic sources, as well as reports of road agencies or institutes. The selection was limited to English language. From the review it is clear that developing CPMs is not a straightforward task: there are many available choices and decisions to be made during the process without definite guidance. This explains the diversity of approaches, techniques, and model types. The paper explains how some fundamental modelling decisions affect practical aspects of modelling safety performance. There is a need to identify CPM solutions that will be scientifically sound and feasible in practitioners’ context. Together with increased communication between researchers and practitioners, these solutions will help overcome the identified challenges and increase use of CPMs.

Short turning pattern for relieving metro congestion during peak hours: the substance coherence of Shanghai, China

Abstract: Urban metro system generally has to deal with intractable heavily passenger loading during peak hours, in which demands are extreme huge in certain stations. However, overcrowding doesn’t ubiquitously exist for all stations and mitigation measures have to be carried out on purpose, respectively. Because of the restrictions on operational costs and avoiding transportation resources wasting, simply increasing dispatch frequency is not rational to solve the problem. Short turning pattern has been proved to be an efficient way to solve the issue, which had been mainly used in urban ground public transport systems. This paper applied short turning pattern to urban metro system and relaxed constraints of the turning-back facility. A mathematical model is proposed to determine the short turning parameters, during which a load factor was introduced as a measurement of overcrowding condition. An empirical case from Shanghai Metro Line 2 was incorporated to demonstrate the effectiveness of the proposed model. The results indicated that the short turning route from Beixinjing to Longyang Rd. in Shanghai Metro Line 2 could effectively relieve overcrowding within the heavy traffic demand zones. Findings of this study could provide valuable suggestions in metro system administration for potential improvement on the operational performance during peak hours.

Options for reducing external costs from freight transport along the Brenner corridor

Abstract: The Brenner is the most heavily travelled transalpine corridor in terms of freight transport. The current modal split tends heavily towards road (71% road – 29% rail), with significant repercussions in terms of environmental and social impacts. Indeed, Alpine areas generate external costs that are up to four times higher than flat areas. The promotion of railway, which is the least impacting transport mode, has thus a strategic value. For this reason, the European Union, the Alpine macro-region and the Tyrol-South Tyrol-Trentino Euroregion are promoting multi-level strategies to reduce the impact generated by freight transport along the Brenner corridor. This paper analyses each level, focussing then on the Euroregion. Its ambitious objective is to achieve a balance between transport modes in the Alpine corridor by 2027, and then to invert them (29% road – 71% rail) by 2035. This paper aims to calculate the savings of external costs deriving from the achievement of this objective. If the aggregated data from 2015 to 2035 are considered and the Euroregion scenario is compared with a prosecution of the current trend, the saving in external costs would amount to €262 M (− 26% than the current trend). This value is not negligible; being equal to 4.7% of the annual public expenditure incurred by the Autonomous Province of Bolzano, it suggests to policy makers the importance of taking up measures to encourage the modal shift.

Transport indicator analysis and comparison of 151 urban areas, based on open source data

Abstract: The accurate analysis and comparison of transport indicators from a large variety of urban areas can help to evaluate the performance of different adopted transport policies. This paper attempts to determine important transport and socio-economic indicators from 151 urban areas and 51 countries, based on comparable, directly observable open-source data such as OpenstreetMap (OSM) and the TomTom database. This is the first, systematic indicator-analysis using recent, open source data from different urban areas around the world. The indicator road kilometers per person, sometimes cited as infrastructure accessibility is calculated by processing OSM data. Information on congestion levels have been taken from the TomTom database and socio-economic data from various, publicly accessible databases. Relations between indicators are identified through correlations and regression models are calibrated, quantifying the relation between transport infrastructure and performance indicators. Three sub-categories of cities with different population sizes (small cities, large cities and metropolises) are defined and studied individually. In addition, a qualitative analysis is performed, putting five different indicators into relation. The main results reconfirm previous findings but with a larger sample size and more comparable data. Good correlation values between infrastructure accessibility, socio-economic indicators, and congestion levels are demonstrated. It is shown that cities with higher GDP have generally built more infrastructure which in turn reduces their congestion levels. In particular, for cities with low population density (above approximately 1500 inh. Per sq.km), more roads per inhabitant lead to lower congestion levels; cities with high population density have in general lower congestion levels if the rail infrastructure per person ratio is high. Furthermore, these cities increasing railways per person is more effective in reducing congestions than increasing road length per person.

Group decision making process for early stage evaluations of infrastructure projects using extended VIKOR method under fuzzy environment

Abstract: This paper considers the evaluations of project alternatives at the early stages of infrastructure project developments. Although it is expected to make important decisions at project early stages, it is rarely possible to obtain reliable data for exact evaluations. To deal with low quality data and the existence of uncertainties, this paper extends the evaluation problem to the fuzzy environment. We propose group decision making process for early stage evaluations of infrastructure projects. The evaluation approach utilizes combination weighting and compromise ranking. We integrate subjective and objective weighting methods to specify criteria weights. Afterwards, we use the VIKOR method to rank alternatives in the presence of conflicting criteria. As a case study, we illustrate the evaluation problem within a railway line reconstruction project. Specifically, the proposed approach is efficiently applied to evaluate and rank several route alternatives considered within the reconstruction project of the regional line Pancevo – Vrsac at Serbian railway network. The provided example illustrates the applicability of the proposed approach to deal with the evaluations at the early stage of the railway line reconstruction. The existence of uncertainties at early stages of project developments is common, so the proposed method is also applicable for other linear infrastructure in transport sector.

Utilitarian and hedonic walking: examining the impact of the built environment on walking behavior

Abstract: Most previous studies have mainly focused on utilitarian or recreational walking and discussed their relationship with the built environment. The point is that most of these studies have not been sensitive to the motivation of trips while travel is a complicated behavior and individuals may have different degrees of motivation and utility for a given trip purpose. Accordingly, because of different utilities of travel, it is more likely that the built environment differently affects walking behavior. This paper aims to clearly distinguish between utilitarian and hedonic walking and then explores how the built environment influences walking behavior. Using data collected from 863 respondents in six diverse neighborhoods in Isfahan, Iran, we developed negative binomial models for two types of walking; namely, utilitarian and hedonic walking. The results reveal some interesting insights: first, both models of walking confirm that neighborhood preferences do not play any important role in explaining walking behavior in our context, inconsistent with previous studies. Second, the objective and perceived built environment factors differently contribute to explaining both types of walking. In this regard, utilitarian walking is affected by mixed land use, residential density, facility accessibility, attractiveness, and walking infrastructure; and hedonic walking is influenced by mixed land use, attractiveness and safety. Third, attitudinal factors and socio-demographic variables also differently appear in the models of walking. The results confirm that it is essential to be more sensitive to the motivation of trips, and suggest a clear policy implication: the individuals’ reactions toward policies intended to increase walking frequency depend partly on the utility for walking.

A new adaptive cruise control strategy and its stabilization effect on traffic flow

Abstract: Connected and autonomous vehicle (CAV) technologies are likely to be gradually implemented over time. In this paper, an adaptive cruise control, named Smart Driver Model (SDM), is proposed to describe the autonomous vehicles flow. The stability criteria is proposed for SDM to judge the stability of homogeneous traffic flow. Numerical simulations were conducted to verify the results of the theoretical analysis. Single-lane vehicle dynamics in a traffic stream with connected and autonomous vehicles are simulated by varying model parameters. Simulation results are consistent with the results of linear stability analysis. As a result, a set of parameters is proposed to investigate the stabilization effect of the proposed model on homogeneous traffic flow considering realistic driving cycle and cut-in condition. By simulating a platoon with a lead vehicle which follows the Urban Dynamometer Driving Schedule (UDDS), we find out that the proposed model can stabilize the traffic flow with proposed parameters. The results from simulation and linear stability analysis show that SDM outperforms the IDM-ACC and the ACC proposed by Milanes and Shladover in terms of stabilization effect on homogeneous traffic flow. The simulation result shows that the SDM-equipped vehicles are able to stabilize the homogeneous traffic flow under cut-in condition.

Digibus©: results from the first self-driving shuttle trial on a public road in Austria

Abstract: From April to November 2017, the non-profit research organisation Salzburg Research conducted the “Digibus© 2017” trial, the first trial of a self-driving shuttle on a public road in Austria. The shuttle from the French company Navya Tech has been tested on a 1.4-km long track in the village of Koppl, which is situated approximately ten kilometres east from the City of Salzburg. The trial in Koppl was one of the first trials worldwide on public roads with mixed traffic in a rural area. The focus of this trial was on the real-world evaluation of a self-driving shuttle for bridging the first/last mile in public transport. From April to November 2017, 240 test drives with 874 passengers covering 341 test kilometres have been conducted. Results show that the technology is ready for testing, but there is still a long way to go for driverless operation, especially in mixed traffic scenarios. The work describes the trial setting, the test route, the process of deploying the shuttle, experiences collected during the trial as well as results from a passenger survey. The accompanying passenger survey with 294 participants revealed high acceptance and a good feeling of safety.

A Nested Logit analysis of the influence of distraction on types of vehicle crashes

Abstract: This work aims to study factors, such as driver characteristics, environmental conditions, and vehicle characteristics, that affect different crash types with a special focus on distraction parameters. For this purpose, distraction factors are divided into five groups: cellphone usage, cognitive distractions, passengers distracting the driver, outside events attracting the driver’s attention, and in-vehicle activities. Taking the crashes that occurred in the USA into account, the crash types are divided into two main groups, single-vehicle crashes and two-vehicle crashes. Since there were different crash types (alternatives) in the dataset and the probable correlation in the unobserved error term, the Nested Logit model is developed. The results of model illustrate that all of the aforementioned distraction-related factors increase the probability of run-off-road crashes, collision with a fixed object, and rear-end crashes. Cognitive distraction increases the probability of collision with a pedestrian. Distractions caused by passengers or out-of-vehicle events increase the probability of sideswipe crashes. By examining how a factor affects multiple crash type outcomes, it is possible to devise countermeasures, improvements to roadway geometry, and traffic control strategies, while minimizing unintended consequences. The results should be of value in the design of educational programs and propose road safety improvement techniques.

Vehicle trajectory at curved sections of two-lane mountain roads: a field study under natural driving conditions

Abstract: The trajectory of a vehicle is comprehensively affected by the interactions between the vehicle, the driving behavior, and the road environment. High-risk driving behaviors and accident-prone road sections can be identified based on the relationship between the trajectory and road geometry. Previous related studies mostly focused on the trajectory deviation at a few points on the road, which cannot capture the continuous variation of the trajectory in an entire curve, and seldom considered the trajectory characteristics along curves with large deflection angles. The aim of this study is to investigate the trajectories passenger cars take on two-lane mountain roads and thus to determine the track patterns and its relevant risks. Field driving experiments were performed on four two-lane mountain highways, and vehicle trajectories under natural driving conditions were acquired. The continuous change in the lateral deviation rate of the trajectory was also determined by putting the measured trajectories into the coordinate frame together with the edge line of roadway. Further, the morphological features of the vehicle trajectory and how it is affected by the highway geometry were analyzed. The following were observed: i) Typical track patterns were determined according to features of LDRT profiles, four patterns for left-hand bends and five patterns for right-hand bends, which can be used to identify crash prone position and reveal the mechanism of crash. ii) Inertia may cause the vehicle to move too close to the outer side of the curve after a cut, for which reason the driver has to correct the trajectory, although overcorrection may move the vehicle into the oncoming lane. iii) A higher speed at curve entry adopt by the driver could result in a larger encroachment into opposite lane or shoulder. iv) The smaller the radius of the horizontal curve, the more frequently the trajectory entered the oncoming lane. These findings could provide a better understanding of the track behavior of passenger cars, judge the safety implications of driver behavior, and thus identify crash prone positioning and the potential mechanisms of head-on crashes, run-off-road and guardrail collisions.

Industry strategies for the promotion of E-mobility under alternative policy and economic scenarios

Abstract: In this study, we consider the European electro-mobility market from an industrial perspective, and focus on effects of market conditions and manufacturer strategies, with the objective to gain insight on what could inhibit the successful market penetration of electric powertrain vehicles. We use the EC-JRC Powertrain Technology Transition Market Agent Model (PTTMAM), a system dynamics model based around the interactions of conceptual market agent groups in the EU. We assess strategies employed by automobile manufacturers towards the development and market penetration of electric vehicles. Impacts on electric powertrain sales shares (up to 2050) related to industrial strategies, represented by learning effect, marketing effort and R&D funding, are presented under different scenarios related to policy, regulation and market conditions. It is concluded from the results presented here that competition between electrical powertrain options may be more inhibitive than competition against conventional counterparts, with both monetary and non-monetary industry support for immature powertrains key to their long-term success when supportive policies are designed to be technology neutral.

Assessing the economic and environmental impacts of urban food systems for public school canteens: case study of Great Lyon region

Abstract: Urban logistics is a subject that interests both city planners and researchers. Although many works are found in non-food distribution, food-based logistics is less studied in an urban context, and sustainability issues of urban food systems remain little analysed, but it is a crucial element for local public authorities. This paper proposes a methodology for assessing scenarios of advanced urban food logistics; more precisely to answer the question of how school canteen distribution scenarios can be assessed in an economic and environmental viewpoint. To deal with those issues, the paper proposes to develop a scenario assessment framework combining a demand estimation model, a transport supply estimation method and a set of evaluation indicators (for both economic and environmental impacts). The demand estimation model generates first a number of meals per canteen then transforms it into a food quantity, based on carrier’s information and other practice’s feedbacks; the transport estimation is made with a combination of route construction algorithms that reproduce the logic of current Transportation Management System (TMS). The economic evaluation is made via direct operational costs estimation (both fixed and variable) and the environmental evaluation using COPERT V for direct emission’s assessment. Three scenarios are assessed: the current situation with the operational warehouse, the use of an alternative platform in another location and the combination of both. To address the application issues, the proposed framework is compared to the use of disconnected commercial tools on the three scenarios. We observe that the first two scenarios are close in terms of travelled distances, times and costs. The third scenario, which involves two platforms, results on higher distances and times, and consequently on higher costs and higher for some of the environmental emissions. That scenario does not allow, with the considered demand, economies of scale (i.e. using less vehicles or in a more consolidated way). When comparing the two assessment methods, the proposed framework results on slightly higher travelled distances and times, but the same number of vehicles. However, results can be considered equivalent since the gap between the two assessment methods is in general around 5% for most indicators. It can be observed that the location of the platform is a key element, not only related to travelled distances, but also to the infrastructures used and their accessibility to the delivery destinations. However, this first assessment shows the interests and opportunities of food city supply solutions and merits further developments. The proposed framework allows to assess food distribution scenarios representing current practices, and would be extended to represent different alternatives of food distribution. Urban logistics is a subject that interests both city planners and researchers. Although many works are found in non-food distribution, food-based logistics is less studied in an urban context, and sustainability issues of urban food systems remain little analysed, but are a crucial element for local public authorities. This paper proposes a methodology for assessing scenarios of advanced urban food logistics; more precisely to answer the question of how urban food logistics supply.

Determinants of urban public transport efficiency: case study of the Czech Republic

Abstract: The aim of this paper is to identify the factors influencing efficiency of urban public transport (UPT) systems and to benchmark Czech UPT systems according to their efficiency. The analysis was carried out on a sample of 19 UPT systems in the Czech Republic during 2010–2015. Efficiency was evaluated through a two-stage analysis. Data envelopment analysis (DEA) was used in the first stage. It was based on three inputs (employees, rolling stock and energy) and one output (passengers). DEA efficiency scores were computed for all 19 systems for each year and under two different assumptions regarding returns to scale. In the second stage of the analysis, DEA scores were used in Tobit regression with a set of operational, socio-economic, and demographic explanatory variables in order to find determinants of efficiency. Several variables were identified as factors increasing efficiency - proportion of drivers, average vehicle age, the presence of tramlines in the city, total vehicle kilometres, and population density. Some variables were identified as decreasing efficiency – ticket price, proportion of subsidies in revenues, and presence of a two-city system. Czech cities with most efficient transport systems were Prague, Brno, Marianske Lazně, Olomouc, and Pilsen. The least efficient cities were Chomutov–Jirkov, Ostrava, and Děcin. The principal lesson from this study is that bigger cities with greater population densities are more efficient than smaller cities, and the key efficiency factors that local authorities have under their control are the ticket price, rate of subsidies, and structure of the city transport system. The paper contributes to current debate about the efficiency of the urban transport systems and their determinants. There was not much difference between the constant and variable returns to scale results. The results from the second stage could help policy makers make the public transport systems more efficient. Future research could be devoted to gaining data on additional operators which would also enable using additional inputs and outputs for DEA analysis.

Characteristics of variable speed limit systems

Abstract: The control algorithm used for deciding on the speed limit in variable speed limit systems is crucial for the performance of the systems. The algorithm is designed to fulfil the purpose of the variable speed limit system, which can be one or several of the following aspects: increasing safety, increasing efficiency and decreasing environmental impacts. Today, many of the control algorithms used in practice are based on fixed thresholds in speed and/or flow. Therefore, they are not necessarily reflecting the current traffic conditions. Control algorithms with a greater level of complexity can be found in the literature. In this paper, four existing control algorithms are investigated to conclude on important characteristics affecting the performance of the variable speed limit system. The purpose of the variable speed limit system and, consequently, the design of the control algorithm differ. Requirements of the investigated control algorithms are that they should be easy to interpret and the execution time should be short. The algorithms are evaluated through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the characteristics of the variable speed limit system and the design of the control algorithm will have effect on the resulting traffic performance, given that the drivers comply with the variable speed limits. Moreover, the time needed to trigger the system, the duration and the size of speed limit reductions, and the location of the congestion are factors of importance for the performance of variable speed limit systems.

City-hubs for smarter cities. The case of Lille “EuraFlandres” interchange

Abstract: The importance of the transport infrastructure role is often described in the attempt to describe the characteristics of a “smart city”. Good planning and organization of communication networks contributes to the development of cities that are more fluid and user-friendly and sustainable, concepts underlying “smart cities”. The paper focuses on the impact on social organisation and on conception of transport intermodal infrastructures such as city-hubs inducing new and smarter practices of transport infrastructure, but also the urban dimension and their insertion through the actual city and, even more, by the creation of an entirely new neighbourhood and the preoccupation of a better quality of life. As part of the European research project FP7 “City-HUB”, 27 interchanges have been studied in nine European countries. The paper emphases on the implementation of the City-HUB interchange typology to the case study of Lille European Metropolis (MEL) where two contingent railway stations, Lille Flandres and Lille Europe, were analysed as a potential unique interchange named “Euraflandres”with socio-economic impacts and the possibility that it may become a “place” of life in the smart city. Within the FP7 project City-HUB a literature review was conducted on the role and characteristics of interchanges in the cities and their contribution to smart cities [29]. For 27 interchanges in nine European countries, we have determined a number of relationships between these transport multimodal interchanges and their environment, and established a typology capturing different interchanges and a scheme for scoring their characteristics in terms of function and logistic dimensions (demand, number of transport modes, services and facilities, location in the city) and their local constraints. The governance framework was specified through carrying out semi-structured interviews with key interchange actors for each City-HUB case study that also questioned about the role of interchanges in local economies and their potential impact on that. The Lille Flandres and Lille Europe as a unique landmark “Euraflandres” were particularly studied to understand their characteristics and role to contribute to a smarter city. Based on the City-HUB typology, the “Euraflandres” gets a score of 9 because its demand is higher than 120,000 in daily passengers, includes 13 public and private transport modes (several PT, long distance coaches, car and bike), is located in the city centre and is included into a local plan of urban development and TOD definition. “Euraflandres” has all the characteristics for becoming an urban Landmark for the city of Lille. We show how this interchange gets a higher role for being a node on the international railway network, and how their inside and outside spatial and functioning reorganisation contribute to ease the use of public transport for travellers by introducing ITS, innovations in ticketing and providing new urban characteristics transforming transport infrastructures into new places to live. Linking the smart city and the development made with “Euraflandres”, we have seen that an opportunity exists to join together the two Lille railway stations and urban Public Transport interchanges in order to combine a great urban interchange. It will procure advantages for increasing the accessibility for all destinations at urban Lille metropolis and regional level, but also at the national and international levels by the possibility offered by the French TGVs running on national network and the Railteam high speed trains such as Eurostar and Thalys. Each type of interchange, according to the identified functions and local constraints, should require the involvement of different stakeholders interchanges and the Lille City-HUB management with its stakeholders’ committees seems to be oriented to make effort for finding an agreed way for reducing conflicts, in order to better plan outcomes and to allow communities to have an influence over the future shape of the places where they live. The community-led participation is the first step to identify requirements and needs of operators (i.e. transport activities including services and facilities) and of users who will perceive the City-HUB as a transport node and a place where to have access to their mobility mode and where to carry out some other activities during their waiting time. Despite existing barriers (complex governance framework, physical barriers, functions and logistics to revise, local constraints), all the stakeholders are willing to improve the visibility and the functionality of these interchanges. “Euraflandres” has the role of developing activities and regenerating the urban environment, by transforming the surrounding area features. All this will make cities more convivial and fluid, answering to two key aspects of the Smart City, when we follow the definition of the smart city as a “fluid”, “intelligent” and “convivial” city by [4]. The extension of the Euralille neighbourhood where is located “Euraflandres”, is part of the Lille urban regeneration, still under construction, will provide new housing and also social housing for low income people and new city amenities transforming it in a new place to live transforming the current two separated interchange towards the future one landmark interchange with a higher share of sustainable and affordable public transport modes share.

Freight and service parking needs and the role of demand management

Abstract: This paper assesses the parking needs of freight and service related commercial activities and identifies the role of demand management in mitigating these needs. To provide a context for the analyses, the authors selected two small commercial areas of about the same number of commercial establishments—one in Troy, NY, and the other in New York City—and applied freight and service trip generation models to estimate the total freight and service traffic generated at these sites. Then, using different assumptions of the amount of time these vehicles spend at a parking location, the authors estimated the number of parking spaces required by time of day under different assumptions of demand management. The results show that parking needs are proportional to the average parking durations. Essentially, the longer the duration the higher the parking needs. In terms of impacts on demand management, the results show that the 100% Off-Hour Deliveries (OHD) program is expected to be the most impactful as it reduces the parking needs by 70–80% during peak hours. In second place, Staggered Deliveries reduces parking needs by about 60% during the peak hours. The third place is occupied by the 30% OHD Scenario and the Receiver-Led Consolidation programs, which are virtually tied, offering about 10–25% reduction. The initial analysis revealed the importance of parking duration as it was shown to be proportional to parking needs; the longer the duration the higher the need for parking. The delivery simulation further bolstered this finding by showing that the optimal case occurs (i.e. minimizing parking duration) the closer the parking location is to the establishment. The further away the vehicle is parked the longer the walking time to the establishment, hence increasing the time the vehicle occupies the parking spot. The strategies applied to the case studies showed that Transportation Demand Management (TDM) strategies are effective in decreasing the number of parking spots needed during peak periods.

Restrained mobility in a high-accessible and migrant-rich area in downtown Beijing

Abstract: Immigrant travel has become an emerging research field in transportation planning. A handful of scholars have studied the travel behavior of residents in immigrant enclaves in North America. However, thus far, there has been no analysis of the travel behavior of residents living in migrant-rich neighborhoods in China. Additionally, previous studies rarely explored whether these (im)migrants could benefit from resources outside the neighborhoods, and the determinants of their travel to destinations outside the neighborhoods. This study aims to fill these research gaps in the literature. We used a migrant-rich area in downtown Beijing as a case study to understand the daily mobility and the determinants, and strategies to enhance mobility of neighborhood residents. To answer the above questions, in-depth interview in Dashilar was used in this study. Eighteen migrant workers were recruited by using snowball sampling, and six local residents were recruited as “observers” to view the mobility of migrant workers from another perspective. The interviews were digitally recorded, transcribed and coded. The research results show that the interviewees had restrained mobility, limited to the area within Dashilar. Their work location was near residence, and they seldom made recreation and social trips. One of the major reasons for this was that their social ties were highly restricted to people from the same hometown. Additionally, time and financial poverty further limited their mobility. Institutional barriers also segregated migrant workers with local people in job market, urban welfare and daily life. In order to improve physical mobility, migrant workers used electric bicycle as their daily travel facility. The use of mobile phone also improved their virtual mobility by facilitating information flow and extending social networks. Moreover, community initiatives such as community activities and volunteers helped to improve their mobility. Dashilar is an area with abundant transport resources and activity destination choices, but migrant workers living there still restrained their daily travel within the neighborhood. Although resources within the neighborhood facilitated daily necessities of migrant workers living in Dashilar, they seldom benefited from the resources outside the neighborhood, which played a larger role in promoting their social and cultural assimilation in the city. Their limited local social ties, individual time and money constraints, and institutional factors all contributed to their limited destination motivations and aspirations. To cope with these challenges, migrant workers and communities both adopted several strategies. These strategies could address the above challenges to some extent, but their limitations also fixed mobility of migrant workers. Combination of Internet of mobile phone and community initiatives was a feasible way to link migrant workers and local people, and help them to improve enlarge mobility space.

Financing urban transportation infrastructure in a multi-actors environment: the role of value capture

Abstract: A family of innovative financial mechanisms and tools for urban public transport, based on the value increment caused by enhanced accessibility, are lately gaining much popularity as a solution to the challenges posed by public financial resources’ shrinkage: Value Capture Finance (VCF). The effectiveness of applied transport financing policies depends significantly on the level of agreement among stakeholders, making collaboration a prerequisite for success. The research presented herein assesses alternative financing options for urban public transportation which are based on the VCF concept. The Multi - Actor Multi-Criteria Analysis (MAMCA) developed by Macharis [1] is used. The methodology is unique in its field, as it includes in-depth involvement of all relevant stakeholders and reveals their way of thinking. The proposed methodological framework is applied to the real-world case study of the under construction metro system of Thessaloniki, Greece. Three different financing scenarios are tested, and the criteria weight elicitation is performed through personal interviews with 70 stakeholders belonging to six different groups, namely: Government/Local Authorities, Transport Authorities, Universities/Research Institutions, Private Sector, Society and Professional Associations. Noteworthy similarities but also contradictions among stakeholder groups emerged, highlighted by the different criteria used for each group. The paper introduces the MAMCA as an ex - ante evaluation method for different VCF mechanisms for urban transportation infrastructure. MAMCA emerges as a robust methodology for this assessment, as it is proved to be capable of dealing with the VCF complexity and multidisciplinary nature.

An analytical model for vehicle miles traveled and carbon emissions for goods delivery scenarios

Abstract: This paper presents an analytical model to contrast the carbon emissions from a number of goods delivery methods. This includes individuals travelling to the store by car, and delivery trucks delivering to homes. While the impact of growing home delivery services has been studied with combinatorial approaches, those approaches do not allow for systematic conclusions regarding when the service provides net benefit. The use of the analytical approach presented here, allows for more systematic relationships to be established between problem parameters, and therefore broader conclusions regarding when delivery services may provide a CO2 benefit over personal travel. Analytical mathematical models are developed to approximate total vehicle miles traveled (VMT) and carbon emissions for a personal vehicle travel scenario, a local depot vehicle travel scenario, and a regional warehouse travel scenario. A graphical heuristic is developed to compare the carbon emissions of a personal vehicle travel scenario and local depot delivery scenario. The analytical approach developed and presented in the paper demonstrates that two key variables drive whether a delivery service or personal travel will provide a lower CO2 solution. These are the emissions ratio, and customer density. The emissions ratio represents the relative emissions impact of the delivery vehicle when compared to the personal vehicle. The results show that with a small number of customers, and low emissions ratio, personal travel is preferred. In contrast, with a high number of customers and low emissions ratio, delivery service is preferred. While other research into the impact of delivery services on CO2 emissions has generally used a combinatorial approach, this paper considers the problem using an analytical model. A detailed simulation can provide locational specificity, but provides less insight into the fundamental drivers of system behavior. The analytical approach exposes the problem’s basic relationships that are independent of local geography and infrastructure. The result is a simple method for identifying context when personal travel, or delivery service, is more CO2 efficient.

Sustainability assessment of retail logistics solutions using external costs analysis: a case-study for the city of Antwerp

Abstract: Policy implementation in the logistics sector might drive unexpected side-effects which sometimes undermine the performance of key economic activities of logistics operators, especially in areas such as transport service, sustainability of operations, etc. Especially for the latter, there is a lack of understanding how the sustainability performance if retail logistics solutions is impacted on by policy implementation and, in turn, by operators’ responsive measures. This paper conducts a sustainability analysis of concrete innovative and already tested retail logistics solutions addressing the research question “what are the effects of retail logistics solutions on total costs and sustainability performance?” The analysis relies on the development and application of an indicator-based framework based on the key sustainability components (economy, environment, society) and enriched by the addition of the transport component. The framework assesses three different scenarios together with a business-as-is one: Urban Consolidation Centre, Tethering and Shared Bus accompanied with a Strengths-Weaknesses analysis. Data are provided by an international food retailer operating within the city of Antwerp, Belgium, but conclusions can be generalized due to wider applicability of measures and solutions examined. External costs analysis shows that higher degree of internalization is achieved in the line-haul transport. Within an urban context, the measures that do not require significant initial investment and broad interventions are assessed as the most sustainable in our analysis. Tethering is the solution that indicates the highest sustainability score. The impact of innovative and already tested solutions relies on a variety of factors: organizational, urban context, type of goods transported, engagement of stakeholders, etc.. In any case, innovation is crucial for urban retail logistics impacting on transport service, society, economy and environment. Any new retail business model should be designed with respect to cost efficiency and through a socially acceptable transition path.

Intelligent personalized ADAS warnings

Abstract: Advanced Driver Assistance Systems (ADAS) have been among the key innovations in the automotive market for over a decade, since they promote traffic safety. This tendency is strengthened even more lately, with the introduction of the autonomous vehicles. A plethora of ADAS exist in the market today, using common warning thresholds for all drivers. However, since we are not all driving the same way, by offering common systems for all the drivers, neither the acceptance nor the effectiveness levels of ADAS are optimal. This manuscript attempts to optimize the Collision Avoidance System (CAS) warning, through intelligent personalized algorithms. Starting with the identification of the dynamic parameters for driving behaviour modeling on the longitudinal road axis, the personalization parameters for ADAS are derived that form the basis for the algorithms developed. Also, based on literature studies, the safety boundaries for warning provision by the CAS are set and implemented in the algorithms. Specific personalized algorithms for the longitudinal road axis behaviour are developed, based on Time to Collision and Time Headway. The proposed algorithms based on Time Headway were assessed on-road with 10 drivers and were positively evaluated by the majority of the participants, with a varying degree of reliability and usability. Based on the results obtained, it can be concluded that with the proposed algorithms, the initial hypothesis of the paper is verified, i.e. personalised warnings would get a greater acceptance by the drivers, of course without braking the safety limits. Further improvements of the algorithm could be achieved, possibly through a better determination of the car following event, since its definition includes a few assumptions.

Flexible car–following models for mixed traffic and weak lane–discipline conditions

Abstract: Heterogeneous mixture of vehicle types and lack of lane discipline are common characteristics of cities in the developing countries. These conditions lead to driving manoeuvres that combine both longitudinal and lateral movements. Modeling this driving behavior tends to be complex and cumbersome, as various phenomena, such as multiple–leader following, should be addressed. This research attempts to simplify mixed traffic modeling by developing a methodology, which is based on data–driven models. The methodology is applied on mixed traffic, weak lane–discipline trajectory data, which have been collected in India. A well–known car–following model, Gipps’ model, is also applied on the same data and is used as a reference benchmark. Regarding the lateral manoeuvres, the focus is given on identification of significant lateral changes, which could indicate a lane–changing situation. Methods that allow monitoring structural changes in regression models could be used for this purpose. The ability of capturing lane changes is explored. A typical example is illustrated and further discussion is motivated.

SEM application to the household travel survey on weekends versus weekdays: the case of Seoul, South Korea

Abstract: This study analyzes the relationship that land use has with weekend travel in comparison to weekday travel. Unlike previous studies, it uses the same sample for two models that are specified to test the relationship separately for weekday and weekend travel. Structural equation modeling is employed to test the land use–travel relationship. A comparison is made using two mode-specific travel measures: trip frequency and travel time. On weekday travel, land use in Seoul tends to reduce automobile trips and to add transit and nonmotorized trips. This does not lead to a reduction in the total frequency of weekday trips. Instead, an overall reduction occurs in the frequency of weekend trips because the addition of transit and nonmotorized trips is less than the reduction of automobile trips. The application of structural equation modeling to a Seoul household travel survey confirms the opposing role of land use in travel mode choices on weekdays versus weekends.

Integrated American-European protocol for safety interventions on existing two-lane rural roads

Abstract: The main purpose was to integrate two strategies for road safety analyses (qualitative: audits, inspections; and quantitative: accident predictions) and develop a possible protocol for the safety interventions on existing two-lane rural road segments. Those road sections do not typically belong to the TEN-network, to which the 2008/96/EC Directive is mainly oriented. Hence, they could lack of methods for designing safety-based interventions. The main research questions were: The integrated protocol, including: 1) the HSM predictive method, 2) the EU Regulations, 3) the local road design standards, 4) some research developments; is applied to real two-lane rural road segments requiring safety-based interventions. Its application is divided in the typical road safety analysis stages. A wide list of possible problems was highlighted and addressed: 1) lack of data, 2) difficult comparison with current road standards in order to identify safety problems, 3) lack of methods for evaluating the skidding risk along the layout, 4) setting speed limits, 5) need for optimizing the selection of countermeasures based on their aims and their timely application, in different recurrent situations, 6) availability and comparison of predictive methods. Based on the problems and solutions discussed, main advantages (1) the systematic approach, 2) the quantitative assessment of benefits, 3) the possible transferability) and disadvantages (difficulties in overcoming the lack of data and calibrated accident prediction models) of the method were remarked.