On the capacity of isolated, curbside bus stops

The maximal rates that buses can discharge from bus stops are examined. Models were developed to estimate these capacities for curbside stops that are isolated from the effects of traffic signals. The models account for key features of the stops, including their target service levels assigned to them by a transit agency. Among other things, the models predict that adding bus berths to a stop can sometimes return disproportionally high gains in capacity. This and other of our findings are at odds with information furnished in professional handbooks.     

Developing environmentally sustainable logistics: Exploring themes and challenges from a logistics service providers’ perspective

The purpose of this paper is to explore themes and challenges in developing environmentally sustainable logistical activities.The approach is explorative with a cross sectional design that takes advantage of ten case studies out of selected logistics service providers (LSPs) operating primarily in the Scandinavian countries.The findings illustrate the major themes by analyzing current and future activities in developing environmentally sustainable logistical activities. In addition, four categories of challenges are identified: customer priorities, managerial complexity, network imbalance, and technological and legislative uncertainties. It is concluded that there is a great need for a holistic perspective where LSPs and product owners together analyze and design future logistical setups.The suggested holistic and integrative model, building on a three-dimensional concurrent engineering framework, provides new opportunities for research. Further research is needed to improve the interrelationship between LSPs and their customers in the development of sustainable logistical solutions.This paper puts forward recommendations for the sustainable development of logistics by combining the results from the case studies with a review of related literature. This will be beneficial for managers and policy makers when they approach sustainable logistical challenges. The emergence and synthesis of themes and challenges are critical for a sustainable society.     

The Intermittent Bus Lane signals setting within an area

Intermittent Bus Lane (IBL) used for bus priority is a lane in which the status of a given section changes according to the presence or not of a bus in its spatial domain: when a bus is approaching such a section, the status of that lane is changed to BUS lane, and after the bus moves out of the section, it becomes a normal lane again, open to general traffic. Therefore when bus services are not so frequent, general traffic will not suffer much, and bus priority can still be obtained. This measure can be operating at a single city block, but if all related control parameters along bus lines are considered together, more time gains can be obtained. In this paper, the basic structure and operation of IBL around a single intersection are briefly introduced, then the construction of an objective function and its relationships with the related priority control parameters along one bus line and their simplifications are described. Finally the calculations of the priority control parameters when there are several connected bus lines within an area and some simulation results are discussed.     

Traffic noise studies in a tropical environment

This paper reports upon a survey of traffic noise annoyance in three residential districts of Trinidad, West Indies. Householder perceptions were solicited by means of a questionnaire survey and direct measurements of traffic noise levels were taken. The results were compared with surveys elsewhere. It was concluded that household status had little effect on annoyance perception, that at L₁₀ levels greater than 70 dB(A) at a dwelling facade the noise level is unacceptable. L₁₀ levels less than 65 dB(A) at the building facade are not perceived as annoying in the environment considered.     

Transferability of standardized regres Person-based approach sion model applied to person-based trip generation

In this paper, the transferability of person-based standardized regression models is analysed using two large-scale origin-destination household surveys with data collected in two Brazilian cities, Sa~o Paulo and Bauru. The models are specified in terms of dummy variables linked to socio-economic attributes which are considered relevant. A model, having home-based daily trips as a dependent variable, is calibrated according to data from the Sa~o Paulo Metropolitan Area and transferred to Bauru, and vice-versa. The transferability of the models is evaluated using the Wald test, which is an objective test applicable to two samples presenting different variances. According to the test, only standardized regression models are transferable. In addition, the performance of the models to estimate the number of trips generated in every zone of the urban areas is verified. The results indicate that the performance of standardized regression models is equivalent to the locally calibrated model.     

What drives the drivers? Predicting turnover intentions in the Belgian bus and coach industry

The bus industry is characterized by demanding jobs and high turnover rates. In this study we gather essential insights that can help companies and industry-level policy makers increase the attractiveness of the profession and design effective retention policies. We compare the factors that induce Belgian drivers to leave their current organization with those inducing them to leave the industry. Key factors increasing the likelihood to consider quitting the company are a negative work-life balance, a lack of social support and a temporary contract. Dominant factors to consider quitting the bus driver profession are a lack of fulfillment, a demanding job environment and a negative work-life balance.     

Dynamic bus holding strategies for schedule reliability: Optimal linear control and performance analysis

As is well known, bus systems are naturally unstable. Without control, buses on a single line tend to bunch, reducing their punctuality in meeting a schedule. Although conventional schedule-based strategies that hold buses at control points can alleviate this problem these methods require too much slack, which slows buses. This delays on-board passengers and increases operating costs.It is shown that dynamic holding strategies based on headways alone cannot help buses adhere to a schedule. Therefore, a family of dynamic holding strategies that use bus arrival deviations from a virtual schedule at the control points is proposed. The virtual schedule is introduced whether the system is run with a published schedule or not. It is shown that with this approach, buses can both closely adhere to a published schedule and maintain regular headways without too much slack.A one-parameter version of the method can be optimized in closed form. This simple method is shown to be near-optimal. To put it in practice, the only data needed in real time are the arrival times of the current bus and the preceding bus at the control point relative to the virtual schedule. The simple method was found to require about 40% less slack than the conventional schedule-based method. When used only to regulate headways it outperforms headway-based methods.     

公路项目经济性与可持续性的相关探讨

文章针对我国目前公路建设项目前期论证中经济性分析存在的不足,将公路项目按照其不同的经济属性进行了较细致的划分,并在此基础上对公路项目的经济性与可持续性进行了详细论述,得出了项目的可持续性分析应成为公路建设项目经济性分析前提的结论。     

Reducing bunching with bus-to-bus cooperation

Schedule-based or headway-based control schemes to reduce bus bunching are not resilient because they cannot prevent buses from losing ground to the buses they follow when disruptions increase the gaps separating them beyond a critical value. (Following buses are then overwhelmed with passengers and cannot process their work quick enough to catch up.) This critical gap problem can be avoided, however, if buses at the leading end of such gaps are given information to cooperate with the ones behind by slowing down.This paper builds on this idea. It proposes an adaptive control scheme that adjusts a bus cruising speed in real-time based on both, its front and rear spacings much as if successive bus pairs were connected by springs. The scheme is shown to yield regular headways with faster bus travel than existing control methods. Its simple and decentralized logic automatically compensates for traffic disruptions and inaccurate bus driver actions. Its hardware and data requirements are minimal.