In-use measurement of the activity, fuel use, and emissions of eight cement mixer trucks operated on each of petroleum diesel and soy-based B20 biodiesel

In-use micro-scale fuel use and emission rates were measured for eight cement mixer trucks using a portable emission measurement system. Each vehicle was tested on petroleum diesel and B20 biodiesel. Average fuel use and emission rates increase monotonically versus engine manifold absolute pressure. A typical duty cycle includes loading at a cement plant, transit while loaded from the cement plant to work site, creeping in a queue of vehicles at the worksite, unloading, and transit without load from the site to the plant. For B20 versus petroleum diesel, there is no significant change in the rate of fuel use, CO₂ emissions, and NO emissions, and significant decreases in emissions for CO, hydrocarbons, and particulate matter. For loaded versus unloaded onroad travel, fuel use and CO₂ emissions rates are approximately 60% higher and the rates for other pollutants are approximately 30–50% higher. A substantial portion of cycle emissions occurred at the work site. Inter-vehicle and intra-cycle variability are also quantified using the micro-scale methodology.     

A model of the travel to work limits of parents

This paper considers the length of time that parents are willing to travel to an existing or new job. Using data for over 12,000 parents it finds that many characteristics were associated with being less likely to be willing to travel to work for at least an hour (roundtrip). These include: being a women, those out of work, having children under 5, being a lone parent and using formal childcare. Professionals and associate professions were more willing to travel for longer periods. In terms of location, those in accessible small towns and rural areas were willing to travel more than those in larger urban areas and those in remote rural areas willing to travel most. Policy implications are also set out.     

Maintenance optimization for transportation systems with demand responsiveness

We present a quadratic programming framework to address the problem of finding optimal maintenance policies for multifacility transportation systems. The proposed model provides a computationally-appealing framework to support decision making, while accounting for functional interdependencies that link the facilities that comprise these systems. In particular, the formulation explicitly captures the bidirectional relationship between demand and deterioration. That is, the state of a facility, i.e., its condition or capacity, impacts the demand/traffic; while simultaneously, demand determines a facility’s deterioration rate. The elements that comprise transportation systems are linked because the state of a facility can impact demand at other facilities. We provide a series of numerical examples to illustrate the advantages of the proposed framework. Specifically, we analyze simple network topologies and traffic patterns where it is optimal to coordinate (synchronize or alternate) interventions for clusters of facilities in transportation systems.     

A structural model of the use of automobiles by households: a case study of urban Australia

Central to the development of transport energy plans are predictions of automobile use. Together with a knowledge of the fuel efficiency of the vehicle fleet, usage acts interdependently to determine the amount of fuel consumed. In this paper we develop an econometric model system at the household level which treats vehicle use, fuel cost, and vehicle fuel efficiency as functionally interdependent. The data is drawn from Wave 1 of a4‐wave panel of Sydney households. The empirical evidence provides new insights into the influences on vehicle use and sets the context for continuing research efforts.     

State ocean policy initiatives in Florida

Abstract

A territorial sea comprising 6.7 million acres of offshore lands extending three geographic miles into the Atlantic Ocean three marine leagues (nine geographic miles) into the Gulf of Mexico makes Florida the second largest “oceanowning”; state in the contiguous United States. Florida's history, climate, economic development, and worldwide reputation have evolved from the state's relationship with the sea. The state is now becoming aware that aggressive management of its ocean resources is necessary to preserve the future of that relationship. The purpose of this article is to present some of Florida's recent legal and policy initiatives that have been directed toward better understanding and management of ocean resources and uses.     

Consolidation and contestability in the European container handling industry

The first part of this paper brings into discussion some recent changes in the dynamics of the European container handling business, in particular as a result of vertical and horizontal integration strategies of container terminal operators. The industry structure has become sufficiently consolidated to raise a fundamental question about whether market forces are sufficient to prevent the abuse of market power. In this context, reference is made to the theory of contestable markets. The second part of the paper looks more closely to the issue of contestability by means of an exploratory and qualitative study of elements that could prevent other players entering or exiting the European container handling market. As such, a first indication is given of the degree of contestability in the container handling industry.     

Improving the estimation of total and direction-based heavy-duty vehicle annual average daily traffic

Abstract

The estimation of annual average daily traffic (AADT) is an important parameter collected and maintained by all US departments of transportation. There have been many past research studies that have focused on ways to improve the estimation of AADT. This paper builds upon previous research and compares eight methods, both traditional and cluster-based methodologies, for aggregating monthly adjustment factors for heavy-duty vehicles (US Department of Transportation Federal Highway Administration (FHWA) vehicle classes 4–13). In addition to the direct comparison between the methodologies, the results from the analysis of variance show at the 95% confidence level that the four cluster-based methods produce statistically lower variance and coefficient of variation over the more traditional approaches. In addition to these findings – which are consistent with previous total volume studies – further analysis is performed to compare total heavy-duty monthly adjustment factors, both directions of traffic, with direction-based monthly adjustment factors. The final results show that the variance as well as the coefficient of variation improve on average by 25% when directional aggregate monthly adjustment factors are used instead of total direction.