•We provide a taxonomy and classification of current ridesharing systems.•The classification reveals issues with the state of the art ridesharing systems.•Literature review provides current ...limitations of ridesharing systems.•We demonstrate future directions of ridesharing systems.
Although ridesharing can provide a wealth of benefits, such as reduced travel costs, congestion, and consequently less pollution, there are a number of challenges that have restricted its widespread adoption. In fact, even at a time when improving communication systems provide real-time detailed information that could be used to facilitate ridesharing, the share of work trips that use ridesharing has decreased by almost 10% in the past 30years.
In this paper we present a classification to understand the key aspects of existing ridesharing systems. The objective is to present a framework that can help identify key challenges in the widespread use of ridesharing and thus foster the development of effective formal ridesharing mechanisms that would overcome these challenges and promote massification.
Bikeshare trip generation in New York City Noland, Robert B.; Smart, Michael J.; Guo, Ziye
Transportation research. Part A, Policy and practice,
12/2016, Letnik:
94
Journal Article
Recenzirano
•A spatial model is developed to examine bikeshare trip generation in New York City.•Estimates are developed for different months, work days versus weekends, and type of user.•Results show that more ...trips are generated near subway stations, as well as in areas with more population and employment.•Bicycle lanes and paths are associated with more casual bikeshare trips.•The model does not perform well when attempting to forecast trip generation at new stations.
Cities around the world and in the US are implementing bikesharing systems, which allow users to access shared bicycles for short trips, typically in the urban core. Yet few scholars have examined the determinants of bikeshare station usage using a fine-grained approach. We estimate a series of Bayesian regression models of trip generation at stations, examining the effects bicycle infrastructure, population and employment, land use mix, and transit access separately by season of the year, weekday/weekend, and user type (subscriber versus casual). We find that bikeshare stations located near busy subway stations and bicycle infrastructure see greater utilization, and that greater population and employment generally predict greater usage. Our findings are nuanced, however; for instance, those areas with more residential population are associated with more trips by subscribers and on both weekdays and non-working days; however, the effect is much stronger on non-working days. Additional nuances can be found in how various land use variables affect bikeshare usage. We use our models, based on 2014 data, to forecast the trips generated at new stations opened in 2015. Results suggest there is large variation in predictive power, partly caused by variation in weather, but also by other factors that cannot be predicted. This leads us to the conclusion that the nuances we find in our inferential analysis are more useful for transportation planners.
•Examines the degree to which bike share replaces car trips.•Bike share operator vehicle use (for bike redistribution) is calculated.•An estimate of bike share’s overall contribution to changes in ...vehicle kilometres traveled is made.•Bike share is shown to reduce car use in all cities included in the analysis, with the exception of London.•Bike share’s effectiveness is dependent on whether it replaces car use.
There are currently more than 700 cities operating bike share programs. Purported benefits of bike share include flexible mobility, physical activity, reduced congestion, emissions and fuel use. Implicit or explicit in the calculation of program benefits are assumptions regarding the modes of travel replaced by bike share journeys. This paper examines the degree to which car trips are replaced by bike share, through an examination of survey and trip data from bike share programs in Melbourne, Brisbane, Washington, D.C., London, and Minneapolis/St. Paul.
A secondary and unique component of this analysis examines motor vehicle support services required for bike share fleet rebalancing and maintenance. These two components are then combined to estimate bike share’s overall contribution to changes in vehicle kilometers traveled.
The results indicate an estimated reduction in motor vehicle use due to bike share of approx. 90,000km per annum in Melbourne and Minneapolis/St. Paul and 243,291km for Washington, D.C. London’s bike share program however recorded an additional 766,341km in motor vehicle use. This was largely due to a low car mode substitution rate and substantial truck use for rebalancing of bicycles. As bike share programs mature, evaluation of their effectiveness in reducing car use may become increasingly important. Researchers can adapt the analytical approach proposed in this paper to assist in the evaluation of current and future bike share programs.
•This study determines the prospective multimodal transportation hubs in the BRI network.•A multi-methodological approach based on network centrality measures and gravity model is proposed.•This ...study integrates air, rail, and maritime mode of transportation in the BRI network.•The importance of air transportation network in the BRI network is demonstrated.•Analytical result suggests primary cities in the BRI network for enhancing international trading outreach.
As the Belt and Road Initiative (BRI) takes root, the Air Transportation Network (ATN) is gaining prominence, as evidenced by the Air Silk Road Initiative proposed in 2017. However, the ATN of the BRI countries and its integration with maritime and rail transport have not been studied. This paper analyzes the network structure of the ATN of the BRI countries. A multi-layer weighted betweenness metric is used to rank the centrality of the hubs in the network based on the connectivity, distance, and traffic between the airports. Using the centrality ranking of the airports to reflect the distribution of traffic demand in the BRI countries, a gravity model is then applied to quantify the centrality of the maritime and rail hubs. Mapping these hubs to their home cities, this paper assesses the current state of the multimodal transport hubs and recommends new hubs to increase the international trading reach of the BRI.
•Social equity is increasingly incorporated as a long-term objective into urban transportation plans.•This research proposes a set of new transit accessibility measures that incorporates both travel ...time and transit fares.•It then uses this measure to evaluate the equitable distribution of accessibility by transit in Montreal, Canada.•Travel time accessibility measures estimate a higher number of jobs that can be reached compared to combined travel time and cost measures.•The degree and impact of these measures varies across the social deciles.•Residents of socially disadvantaged areas have more equitable accessibility to jobs using transit.
Social equity is increasingly incorporated as a long-term objective into urban transportation plans. Researchers use accessibility measures to assess equity issues, such as determining the amount of jobs reachable by marginalized groups within a defined travel time threshold and compare these measures across socioeconomic categories. However, allocating public transit resources in an equitable manner is not only related to travel time, but also related to the out-of-pocket cost of transit, which can represent a major barrier to accessibility for many disadvantaged groups. Therefore, this research proposes a set of new accessibility measures that incorporates both travel time and transit fares. It then applies those measures to determine whether people residing in socially disadvantaged neighborhoods in Montreal, Canada experience the same levels of transit accessibility as those living in other neighborhoods. Results are presented in terms of regional accessibility and trends by social indicator decile. Travel time accessibility measures estimate a higher number of jobs that can be reached compared to combined travel time and cost measures. However, the degree and impact of these measures varies across the social deciles. Compared to other groups in the region, residents of socially disadvantaged areas have more equitable accessibility to jobs using transit; this is reflected in smaller decreases in accessibility when fare costs are included. Generating new measures of accessibility combining travel time and transit fares provides more accurate measures that can be easily communicated by transportation planners and engineers to policy makers and the public since it translates accessibility measures to a dollar value.
The task assignment for vehicles plays an important role in urban transportation system, which is the key to cost reduction and efficiency improvement. The development of information technology and ...the emergence of “sharing economy” create a more convenient transportation mode, but also bring a greater challenge to efficient operation of urban transportation system. On the one hand, considering the complex and dynamic environment of urban transportation, an efficient method for assigning transportation tasks to idle vehicles is desired. On the other hand, to meet the users' expectations on immediate response of vehicle, the task assignment problem with dynamic arrival remains to be resolved. In this study, we propose a dynamic task assignment method for vehicles in urban transportation system based on the multi-agent reinforcement learning (RL). The transportation task assignment problem is transformed into a stochastic game process from vehicles’ perspective, and then an extended actor-critic (AC) algorithm is employed to obtain the optimal strategy. Based on the proposed method, vehicles can independently make decisions in real time, thus eliminating a lot of communication cost. Compared with the methods based on first-come-first-service (FCFS) rule and classic contract net algorithm (CNA), the results show that the proposed method can obtain higher acceptance rate and profit rate in the service cycle.
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•Transport planning and policymaking face a time of deep uncertainty over the future.•Scenario planning reveals divergent, plausible futures for connectivity and society.•Decision ...makers must confront decision biases and embrace flexible design.•Physical mobility, spatial proximity and digital connectivity should frame policy.•A regime-testing rather than regime-compliant policymaking pathway is needed.
Uncertainty of outcome is widely recognised as a concern facing decision-makers and their advisors. In a number of spheres of policy, it appears uncertainty has intensified in the face of globalisation, economic instability, climate change, technological innovation and changing consumer preferences. How can planners and policymakers plan for an uncertain future? There is growing interest in, and use of, techniques that can help decision-making processes where deep uncertainty is involved. This paper is based upon one of the most recent international examples of a foresight exercise employed to examine uncertainty – specifically that which concerns uncertainty over the nature and extent of future demand for car travel. The principal focus of the paper is on the insights and guidance this examination of uncertainty brings forth for transport planning and policymaking. To accommodate deep uncertainty requires a flexible and open approach in terms of how policy and investment possibilities are formulated and judged. The paper argues for a focus upon the Triple Access System of spatial proximity, physical mobility and digital connectivity as a framework for policy and investment decisions that can harness flexibility and resilience. Uncertainty becomes an opportunity for decision-makers with the realisation that they are shaping the future rather than (only) responding to a predicted future. The paper outlines two forms of policymaking pathway: regime-compliant (in which adherence to trends and the nature of the world we have known pushes policy) and regime-testing (in which the nature of the world as we have known it is brought into question and vision pulls policy decisions). Stronger orientation towards regime-testing to assist in managing an uncertain future is advocated.
Among the attempts made worldwide to foster urban and transport sustainability, transit-oriented development (TOD) certainly is one of the most successful. Since the TOD concept appeared in the late ...1980s, it has received increasing attention from researchers and practitioners as a way to merge together transport engineering and planning, land-use planning, and urban design for providing comprehensive solutions to contemporary urban problems. This attention has notably led to the publication of over 300 articles explicitly concerned with TOD in Web of Science journals, as well as to many implementations of the concept, some already completed and others underway (as, for example, the Grand Paris Project in France and Moscow Central Circle in Russia). Essentially, TOD can be described as land-use and transport planning that makes sustainable transport modes convenient and desirable, and that maximizes the efficiency of transport services by concentrating urban development around transit stations. However, as TOD projects started to be implemented worldwide, it became evident that their outcomes could be quite diverse, revealing that in practice the results of a project would depend on a wide variety of factors, trends and complex interrelations between them. In this article, we aim to provide a comprehensive, systematic and up-to-date review of TOD research achievements and challenges. We start by presenting the TOD concept, framing it in the theory of urban planning, and by describing the different typologies of TOD proposed in the literature. Then, we review the vast research dedicated to the study of TOD effects, distinguishing impacts on travel behavior, real-estate prices, residential location, urban form, and community life. The next subject we look at is TOD planning, focusing separately on policy issues and decision-support tools. In the final part of the article, based on the analysis of previous literature, we identify the main gaps and challenges that TOD research needs to address in the future.
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