Towards integrated traveller information

Traveller information provision has become a key government priority in the UK following the publication of its Transport White Paper in July 1998. Developments are already underway for the integration of information systems across different public transport modes and between public transport information systems covering different regions. The Highways Agency (which is responsible for managing the strategic road network in the UK) is also advancing in its development of information databases and systems for the motorist. This paper considers the prospect of providing travellers with multimodal information with integration of driver information with public transport information. If such integration can be achieved then travellers, and in particular drivers, have the prospect of being presented with comparable information on travel options across modes. An integrated information service has a great potential to inform and influence travel choices. The paper considers the issue of travel choices and the role that information can play particularly in the context of mode choice. The political (UK) and technological climate for information provision is outlined. The paper identifies issues that will need to be addressed to identify the requirements from, and potential benefits of, integrated information, and the obstacles and challenges likely to be faced in moving towards it. Driver reactions, in particular, to the prospect of integrated information provision are fundamental to the assessment of its potential importance and value.     

One manufacturer's approach to improving jet transport fuel efficiency

In the face of rapidly escalating costs of aircraft fuel, since the early 1970s, the aerospace industry has embarked on a program of measures to reduce fuel consumption. This article describes an integrated set of measures which have been undertaken by Lockheed‐California to improve the fuel requirements of the Tristar, a wide‐bodied three engine medium to long range aircraft. Measures include operational changes, improvements to maintenance practices, long term hardware modifications and technological advances.     

The evolution of urban traffic control: changing policy and technology

Abstract

The history of urban traffic control (UTC) throughout the past century has been a continued race to keep pace with ever more complex policy objectives and consistently increasing vehicle demand. Many benefits can be observed from an efficient UTC system, such as reduced congestion, increased economic efficiency and improved road safety and air quality.

There have been significant advances in vehicle detection and communication technologies which have enabled a series of step changes in the capabilities of UTC systems, from early (fixed time) signal plans to modern integrated systems. A variety of UTC systems have been implemented throughout the world, each with individual strengths and weaknesses; this paper seeks to compare the leading commercial systems (and some less well known systems) to highlight the key characteristics and differences before assessing whether the current UTC systems are capable of meeting modern transport policy obligations and desires.

This paper then moves on to consider current and future transport policy and the technological landscape in which UTC will need to operate over the coming decades, where technological advancements are expected to move UTC from an era of limited data availability to an era of data abundance.     

Economic factors affecting the registration of lower CO2 emitting aircraft in Europe

We examine the various forces influencing the development and uptake of environmentally beneficial technical changes, focusing on airline technology. Within this context, we consider not only the nature of competition within the final market in which aircraft, an intermediate product, are sold, but also that of the product market itself, the commercial airline industry. The reasons for the gradual reduction in CO₂ per seat per aircraft movement in aircraft design are examined in terms of the real costs of aviation fuel, changes in the nature of the supply industry, the movement towards carbon cap-trade policies, and endogenous technical progress in the technology of the industry. The latter being taken as an empirical proxy for the role market forms play in influencing the fuel efficiency of the types of aircraft used. The results support the existence of these latter forces on the demand for aircraft types, allowing for other influences that affect aircraft technology.     

Technical Challenges of Super-Long Mountainous Tunnels at Great Depth北大核心CSCD

There are various technical challenges faced by the super-long mountainous tunnelling at great depth,and new requirements are arising in terms of the geological investigation, construction period, special geological condi-tions (high ground stress, high geothermal temperature and high-pressure groundwater), disaster prevention & evacua-tion, and social development. Based on an analysis of above mentioned technical challenges, this paper presents tech-nical views on solutions to those challenges and specifies the objectives of related technical development in the fu-ture. To improve the validity and accuracy of the geophysical prospecting, it is necessary to not only increase the accu-racy of ground geophysical exploration at great depth, but also carry out research on the application of such tech-niques to tunnel investigation as airborne geophysical prospecting and HDD combined with borehole geophysical ex-ploration. To maximize the benefits of tunnel projects, it is of importance that more attention should be paid to thoseissues relating to the tunnel design concept, such as the multiple functions of tunnel projects, energy saving andemission reduction, and environmental protection. As for tunnel support theories, in addition to optimizing the currenttheories, some unconventionally new lining theories need to be studied to make the tunnel structure more durable andeconomical. It is also suggested that, in terms of construction, sustained efforts should be put into the development ofinnovative tunnelling techniques for a better, faster and more economical tunnelling, as well as the realization of intel-ligent mechanized tunnelling. When it comes to operation, it is obvious that there will be a trend towards intelligent maintenance in the future. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

An empirical investigation on consumers’ intentions towards autonomous driving

Major steps towards implementation of autonomous and connected transport are being taken nowadays. The trend of automation technology being used in vehicles by the most important vehicle manufacturing industries is expected to move closer to high or fully Autonomous Vehicles (AVs) through technological advancements in sectors of robotics and artificial intelligence. Vehicles with autonomous driving capabilities are planning to be available on market, in full scale, in the next years. In the longer term substantial benefits are mainly expected for accessibility to transport, safety, traffic flow, emissions, fuel use and comfort. All these potential societal benefits will not be achieved unless AVs are accepted and used by a critical mass of people. Addressing these challenges, this paper: (a) proposes a technology acceptance modelling process by extending the original Technology Acceptance Model (TAM) to explain and predict consumers’ intensions towards AVs, (b) based on the proposed TAM-extended framework, a 30-question survey was conducted in order to investigate the factors influencing consumers’ intensions to use and accept AVs. Results show that the constructs of perceived usefulness, perceived ease to use, perceived trust and social influence, are all useful predictors of behavioral intentions to have or use AVs, with perceived usefulness having the strongest impact. The insights derived from this study could significantly contribute to ongoing research related to technology acceptance of AVs and are expected to allow automobile industries to improve their design and technology.     

The flying sidekick traveling salesman problem: Optimization of drone-assisted parcel delivery

Once limited to the military domain, unmanned aerial vehicles are now poised to gain widespread adoption in the commercial sector. One such application is to deploy these aircraft, also known as drones, for last-mile delivery in logistics operations. While significant research efforts are underway to improve the technology required to enable delivery by drone, less attention has been focused on the operational challenges associated with leveraging this technology. This paper provides two mathematical programming models aimed at optimal routing and scheduling of unmanned aircraft, and delivery trucks, in this new paradigm of parcel delivery. In particular, a unique variant of the classical vehicle routing problem is introduced, motivated by a scenario in which an unmanned aerial vehicle works in collaboration with a traditional delivery truck to distribute parcels. We present mixed integer linear programming formulations for two delivery-by-drone problems, along with two simple, yet effective, heuristic solution approaches to solve problems of practical size. Solutions to these problems will facilitate the adoption of unmanned aircraft for last-mile delivery. Such a delivery system is expected to provide faster receipt of customer orders at less cost to the distributor and with reduced environmental impacts. A numerical analysis demonstrates the effectiveness of the heuristics and investigates the tradeoffs between using drones with faster flight speeds versus longer endurance.     

船用燃气轮机动力装置技术特点研究及发展趋势展望

文章介绍了燃气轮机应用于船舶动力装置的技术特点与应用情况,重点阐述了其主要面临的技术问题,并对其未来技术发展趋势进行了展望。就目前而言,尽管我国船用燃气轮机的技术水平相比世界先进水平仍有一定的技术差距,但随着相关技术及制度的不断优化及完善,终将得以迎头赶上。     

Effective aircraft maintenance schedule adjustment following incidents

In the real world, planned aircraft maintenance schedules are often affected by incidents. Airlines may thus need to adjust their aircraft maintenance schedules following the incidents that occur during routine operations. In tradition, such aircraft maintenance schedule adjustment has been performed manually, a process which is neither effective nor efficient, especially when the problem scale is large. In this study, an aircraft maintenance schedule adjustment model is developed, with the objective of minimizing the total system cost, subject to the related operating constraints. The model is formulated as a zero-one integer program and is solved using a mathematical programing solver. The effectiveness of the model is evaluated by application to a case study using data from an aircraft maintenance center in Taiwan. The test results show the proposed model, as well as the scheduling rules abstracted from the results are useful for the decision maker to adjust good maintenance schedules.     

The impact of strategic management and fleet planning on airline efficiency - A random effects Tobit model based on DEA efficiency scores

As a result of the liberalisation of airline markets; the strong growth of low cost carriers; the high volatility in fuel prices; and the recent global financial crisis, the cost pressure that airlines face is very substantial. In order to survive in these very competitive environments, information on what factors impact on costs and efficiency of airlines is crucial in guiding strategic change. To evaluate key determinants of 58 passenger airlines’ efficiency, this paper applies a two-stage Data Envelopment Analysis (DEA) approach, with partially bootstrapped random effects Tobit regressions in the second stage. Our results suggest that the effects of route optimisation, in the sense of average stage length of the fleet, are limited to airline technical efficiency. We show that airline size and key fleet mix characteristics, such as aircraft size and number of different aircraft families in the fleet, are more relevant to successful cost management of airlines since they have significant impacts on all three types of airline efficiency: technical, allocative and, ultimately, cost efficiency. Our results also show that despite the fuel saving benefits of younger aircraft, the age of an airline’s fleet has no significant impact on its technical efficiency, but does have a positive impact on its allocative and cost efficiency.     

绿色高速公路运营期在线监测技术体系研究——环境、气象、能耗监测

为了做好高速公路运营期环境、气象、能耗的在线监测,保证行车安全、提升服务功能、减少碳排放,本文针对高速公路运营期的空气、水、噪声等环境污染问题,气象灾害导致的交通事故问题,运管养护能源消耗量大的问题,提出建立绿色高速公路在线监测技术体系。该体系基于环境监测、气象监测、能耗监测三个方面,明确监测布点选择及相应指标,开展基础数据采集,并架构在线监测系统平台进行综合分析。该体系面向高速公路管理部门,可为高速公路管理决策提供技术支持,为运营期在线监测技术的集成应用奠定理论基础。     

A sequential group decision-making approach to strategic planning for the development of commercial vehicle operations systems

This paper explores a new sequential decision methodology which integrates a generalized sequential probability ratio testing approach with a strategy-value matrix analytical tool to determine the developmental priorities of commercial vehicle operations (CVO) technical packages for CVO time-based strategic planning. The proposed method executes a sequential decision algorithm utilizing the strategic elements of strategy-value matrices which are estimated on the basis of the data collected from the survey respondents. In the process of sequential decision making, the identification of a specific CVO value-added technology package can be made once the condition of the minimum group decision-making cost is met. In addition to methodology development, a real case study together with a nation-wide mail survey to aid the estimation of the strategy-value matrix samples which were used as inputs to the proposed sequential decision algorithm was conducted in Taiwan to demonstrate the feasibility of the proposed method. Utilizing the proposed method, we determined efficiently the developmental priorities of CVO technology packages for short-term, mid-term, and long-term strategic plans, respectively. Our analyses results indicated that the CVO package used for fleet management appears to be the most urgently needed in the short-term CVO strategic plan; value-added technology packages including: (1) data warehousing, (2) information technology, (3) integration with the supply chain management (SCM) platform, (4) freight mobility, (5) integration with advanced traffic management systems (ATMS), and (6) extension for intermodal operations are assigned to the mid-term CVO strategic plan; and others including: (1) freight administration, (2) HAZMAT management, (3) on-board safety monitoring, and (4) roadside safety inspections are involved in the long-term CVO strategic plan. We expect that this study can make available the proposed decision-making support method with benefits not only for planning CVO development strategies, but also for re-examining the role of commercial vehicle operations in a comprehensive extent.     

An optimization model for a real-time flight scheduling problem

Although airlines plan aircraft routes and crew schedules in advance, perturbations occur everyday. As a result, flight schedules may become infeasible and would need to be updated. This Day of Operations Scheduling problem impacts the entire system of an airline as the decisions enforced are final. When perturbations are relatively small, the airline may be able to at least preserve the planned aircraft and crew itineraries. We propose a model that determines new flight schedules based on planned crew transfers, rest periods, passenger connections, and maintenance. Its dual is shown to be a network model, hence solvable in a real-time environment. In addition, it can be used in more sophisticated operational and planning systems.     

The influence of attitude towards individuals’ choice for a remotely piloted commercial flight: A latent class logit approach

The Remotely Piloted Commercial Passenger Aircraft Attitude Scale (RPCPAAS) was created to measure positive and negative attitudes towards a new and plausible form of air travel. This information was then used, in combination with a latent class logit model built on data generated from a stated choice experiment to gain insight into the choice behaviour between conventionally piloted aircraft (CPA) with a pilot on-board and remotely piloted aircraft (RPA) with a pilot on the ground. The results revealed that individuals, on-average, if presented a choice between a CPA and a RPA of equivalent attributes, would elect for the CPA option. However, there is variability in the passengers’ sensitivity to various flight attributes, and these sensitivities were influenced by individuals’ attitude towards the new technology (i.e., RPA). From an operational perspective, and assuming that one day passengers of commercial airlines are offered the choice between CPA and RPA, the strategies employed by airlines to encourage the use of the new technology need to be different, based on individuals’ attitude towards RPA.     

Ridesharing: The state-of-the-art and future directions

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 30 years.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.     

Metaheuristics for efficient aircraft scheduling and re-routing at busy terminal control areas

Intelligent decision support systems for the real-time management of landing and take-off operations can be very effective in helping air traffic controllers to limit airport congestion at busy terminal control areas. The key optimization problem to be solved regards the assignment of airport resources to take-off and landing aircraft and the aircraft sequencing on them. The problem can be formulated as a mixed integer linear program. However, since this problem is strongly NP-hard, heuristic algorithms are typically adopted in practice to compute good quality solutions in a short computation time. This paper presents a number of algorithmic improvements implemented in the AGLIBRARY solver (a state-of-the-art optimization solver to deal with complex routing and scheduling problems) in order to improve the possibility of finding good quality solutions quickly. The proposed framework starts from a good initial solution for the aircraft scheduling problem with fixed routes (given the resources to be traversed by each aircraft), computed via a truncated branch-and-bound algorithm. A metaheuristic is then applied to improve the solution by re-routing some aircraft in the terminal control area. New metaheuristics, based on variable neighbourhood search, tabu search and hybrid schemes, are introduced. Computational experiments are performed on an Italian terminal control area under various types of disturbances, including multiple aircraft delays and a temporarily disrupted runway. The metaheuristics achieve solutions of remarkable quality, within a small computation time, compared with a commercial solver and with the previous versions of AGLIBRARY.     

绿色公路技术LCA评价体系及效益分析

针对各类绿色公路技术难以横向比较的问题,文章从技术可行性、经济效益、节能减排效益等方面,提出建立绿色公路技术LCA评价体系,并以G312苏州西段工程为例进行综合效益分析,其综合效益最为显著,具备规模化、资源化、投资适宜的绿色公路技术;技术瓶颈问题的突破和创新,是推进绿色公路发展的根本动力;将绿色理念融入公路建设的全生命周期的前提,是因地制宜的前期规划布局研究,也是合理选择适宜绿色公路技术的基础。     

Estimating bike-share trips using station level data

Bicycle sharing systems (BSS) have increased in number rapidly since 2007. The potential benefits of BSS, mainly sustainability, health and equity, have encouraged their adoption through support and promotion by mayors in Europe and North America alike. In most cases municipal governments desire their BSS to be successful and, with few exceptions, state them as being so. New technological improvements have dramatically simplified the use and enforcement of bicycle return, resulting in the widespread adoption of BSS. Unfortunately little evaluation of the effectiveness of differently distributed and managed BSS has taken place. Comparing BSS systems quantitatively is challenging due to the limited data made available. The metrics of success presented by municipalities are often too general or incomparable to others making relative evaluations of BSS success arduous. This paper presents multiple methodologies allowing the estimation of the number of daily trips, the most significant measure of BSS usage, based on data that is commonly available, the number of bicycles available at a station over time. Results provide model coefficients as well as trip count estimates for select cities. Of four spatial and temporal aggregate models the day level aggregation is found to be most effective for estimation. In addition to trip estimation this work provides a rigorous formalization of station level data and the ability to distinguish spatio-temporal rebalancing quantities as well as new characteristics of BSS station use.     

Achieving environmental sustainability beyond technological improvements: Potential role of high-speed rail in the United States of America

In order to reduce energy use and cut emissions that contribute to climate change, countries need to radically reinvent their fossil-fuel intensive transportation systems. As a major consumer of energy and contributor to greenhouse gas (GHG) emissions, the U.S. transportation sector faces extraordinary challenges in the twenty-first century. Transportation in the U.S. depends heavily on fossil-fuel dependent cars and planes to the near exclusion of more energy-efficient electric trains. In order to address this concern, some policy makers refer to “technological optimism” which seeks no systemic change but instead focuses on employing technology to reduce the energy demand and environmental impact of the status quo. On the other hand, some researchers suggest a systematic paradigm shift away from cars and planes to intermodal systems that improve the sustainability of the system as a whole. High-speed rail (HSR) is arguably such an investment that can further this shift and help to achieve a more diversified and balanced transportation system. In this respect, by largely examining the role of the U.S. cars and planes “culture” in the economy, this paper elaborates on how building a HSR system may help U.S. advance towards environmental sustainability in transportation, make a break from the status quo, and create a more balanced, multimodal transportation system that will improve the quality and efficiency of travel.     

Impact of environmental assessment and budgetary restrictions in pavement maintenance decisions: Application to an urban network

Road agencies are facing the challenges of aging pavements, deteriorating networks, and insufficient maintenance budgets. This study addresses two limitations in the current state of practice in pavement management. First, because the evaluation of maintenance strategies has traditionally focused on economic and technical aspects, it neglects the environmental impact of maintenance decisions. Second, current management systems often provide a unique, optimised pavement maintenance strategy based on a specific objective(s) and constraint(s). The main objective of the study is to analyse the effect of including environmental aspects and funding availability in the design of maintenance strategies. To achieve this objective, the study followed a three-step methodology. First, this study reviews existing practices on pavement maintenance and the criteria considered to trigger the application of maintenance treatments and their effects on pavement condition. Then, maintenance strategies are optimised considering three levels of budgetary capacity and a sustainable evaluation which incorporates technical, economic, and environmental aspects over the pavement lifecycle. Finally, a case study dealing with an urban pavement network in Chile is analysed. Results obtained from this case study show that an increment of 2% in maintenance budget allows to account for more sustainable maintenance decisions, such as cold in-place recycling and full-depth slab repair, whose greenhouse gas emissions are lower than other alternatives. Results also show that functional asphalt overlay and microsurfacing are more recommended in flexible pavements when budgetary restrictions are low, whereas recommended treatments for rigid pavements exhibit small variability with budgetary restrictions.