The Gini index of demand imbalances in public transport

Transportation - The paper studies a general bidirectional public transport line along which demand varies by line section. The length of line sections also varies, and therefore their contribution...     

Evaluating the impact of PSC inspectors’ professional profile: a case study of the Spanish Maritime Administration

Full-scale globalisation of trade has been accompanied by a progressive liberalisation of maritime transport. The proliferation of open registries has created a situation in which Port State Control (PSC) has become much more effective than the feeble or non-existent control exercised by those States. This study has been conducted on the influence of the professional profile of inspectors on inspection results. The objective of our paper was to evaluate the impact of PSC inspectors’ professional profile by conducting a case study of the Spanish Maritime Administration. The paper concludes with a discussion of the correlation between deficiencies detected and professional profiles.     

Privatization of urban transit: The Los Angeles jitney experience

This paper reports on a recent attempt to provide private transit in the form of jitney service in downtown Los Angeles. It describes the process undertaken to initiate jitney service and the resultant organization's structure and operation. A survey of jitney passengers provided information on the users and their tripmaking characteristics. A group of loyal jitney riders emerged who patronized the service because of its lower travel times and more personalized atmosphere. This group formed the core of frequent users. The Los Angeles experience is analyzed in terms of the economic feasibility of jitney service and the impact on the financial status of public transit. The public transit agency experienced a slight negative financial impact as a result of the jitney service. Ridership during peak hours declined somewhat but the jitney service was not frequent enough to carry sufficient passengers to allow the transit agency to cut costly peak hour service. This analysis shows that the jitney service ultimately was not an economically successful operation. The factors which would have increased the likelihood of success were increased frequency of service and higher fares, which would have been sustainable if not for unexpected developments in public transit financing. A labor pool willing to work for low wages, high transit use in the central city, relatively high transit fares and the availability of inexpensive vehicles appear to be prerequisites to a successful urban jitney operation.     

A continuous network design model in stochastic user equilibrium based on sensitivity analysis

The continuous network design problem (CNDP) is known to be difficult to solve due to the intrinsic properties of non‐convexity and nonlinearity. Such kinds of CNDP can be formulated as a bi‐level programme, in which the upper level represents the designer's decisions and the lower level the travellers' responses. Formulations of this kind can be classified as either Stackelberg approaches or Nash ones according to the relationship between the upper level and the lower level parts. This paper formulates the CNDP for road expansion based on Stackelberg game where leader and follower exist, and allows for variety of travellers' behaviour in choosing their routes. In order to solve the problem by the Stackelberg approach, we need a relation between link flows and design parameters. For this purpose, we use a logit route choice model, which provides this in an explicit closed‐form function. This model is applied to two example road networks to test and briefly compare the results between the Stackelberg and Nash approaches to explore the differences between them.     

Towards measures of affective and eudaimonic subjective well-being in the travel domain

Studies of the connections between transportation and subjective well-being (SWB) require a clear understanding of the conceptual composition of travel-related SWB as well as psychometric instruments to measure these complex topics. Well-established psychological scales for measuring general SWB—including both hedonic (affective and cognitive) and eudaimonic aspects—are difficult to adapt or have yet to be tested in the travel domain. Existing measures of travel liking and travel satisfaction are somewhat inadequate for these purposes, especially for representing eudaimonia. Using a questionnaire survey of 680 commuters in the Portland, Oregon, region, exploratory and confirmatory factor analyses examined responses to a total of 42 items. Results suggested four-factor measurement models of both travel affect (Enjoyment, Attentiveness, Distress, and Fear) and travel eudaimonia (Health, Competence, Autonomy, and Security). Despite some limitations and opportunities for enhancements, these models show promise as ways of measuring affective and eudaimonic SWB in the travel domain for future studies and travel surveys.

     

A socioeconomic analysis of commuting professionals

Transportation - Everyday commuting as a mobility phenomenon is well-investigated and has been the topic of many contributions. Nevertheless, the distinct determinants of the commuting...     

Mathematical model for optimising the sequence for clearing snow from the manoeuvring area during winter operations

This article considers the optimisation of the sequence for clearing snow from stretches of the manoeuvring area of an airport. This issue involves the optimisation of limited resources to remove snow from taxiways and runways thereby leaving them in an acceptable condition for operating aircraft. The airfield is divided into subsets of significant stretches for the purpose of operations and target times are established during which these are open to aircraft traffic. The document contains several mathematical models each with different functions, such as the end time of the process, the sum of the end times of each stretch and gap between the estimated and the real end times. During this process, we introduce different operating restrictions on partial fulfilment of the operational targets as applied to zones of special interest, or relating to the operation of the snow‐clearing machines. The problem is solved by optimisation based on linear programming. The article gives the results of the computational tests carried out on five distinct models of the manoeuvring area, which cover increasingly complex situations and larger areas. The mathematical model is particularised for the case of the manoeuvring area of Adolfo Suarez Madrid—Barajas Airport. Copyright © 2016 John Wiley & Sons, Ltd.

Highlights
• Optimal sequence for clearing snow from the manoeuvring area of an airport.
• Contains optimising algorithms solved using CPLEX LP‐based tree search.
• Restrictions on partial fulfilment of operational targets applied to subsets of significant stretches, used for planning the operation of snow‐clearing machines.
• Model applied to the case of the manoeuvring area of Adolfo Suárez Madrid Barajas Airport.
• Conclusions are given on the results of the computational tests carried out. There are five models of the manoeuvring area which cover increasingly complex situations and larger areas.

     

Trip generation of vulnerable populations in three Canadian cities: a spatial ordered probit approach

This paper provides an analysis of trip generation of three vulnerable groups: single-parent families, low income households, and the elderly. It compares the mobility of these groups to that of the general population in three Canadian urban areas of Hamilton, Montreal and Toronto, based on data from large-sample metropolitan transport surveys. An ordered probit model with spatially expanded coefficients is used for the analysis. Spatial expansion shows that there are spatial mobility trends for elderly populations and low-income populations even after socio-economic attributes are accounted for. Such spatial differences are not generally found for single parent families. This novel spatial analysis provides clues as to where vulnerable populations may experience greater degrees of social exclusion. It provides information to help prioritize transportation infrastructure projects or other social programs to take into account the needs of vulnerable populations with the lowest levels of mobility.     

On Safety in Dismantling Temporary Strut of Super-large Tunnels with Double-layer Primary Support北大核心CSCD

More and more multiple-track tunnels and super-large section tunnels have been built, and disman- tling of temporary strut is a weak point of the whole structure during force transfer when the secondary lining is con- structed. It is significant to guarantee structure safety during dismantling of temporary strut. Little systematic re- search on safety in dismantling of temporary strut of the super-large section tunnel with double-layer primary support has been conducted, so the internal force and security of the two-layer primary support of the Xinkaotang tunnel were analyzed by a numerical analysis and site measurement, and it proves the effect of two-layer primary support on the safety during strut dismantling. The research results indicate that: (1) with constant support thickness and one-time longitudinal dismantling length, the safety factor of secondary primary support is larger than that of the first primary support, and the safety factor of the first primary support is larger than that of the single-layer primary support. Change range of safety factor for the first primary support is smaller than that of the single-layer primary support, and the safe factor for the single-layer primary support is smaller than that of the secondary primary support; (2) with the same support pattern, the safety factors increase firstly and then decrease with an increase of the onetime dismantling length. The calculated results of various cases show that the reasonable one-time dismantling length for this project is about 9 m. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.