Carlos González-Calderón

Improving Freight System Performance in Metropolitan Areas: A Planning Guide

This report provides a regional public planning guide that identifies potential strategies and practical solutions for public and private stakeholders to improve freight movement system performance in diverse metropolitan areas. The Guide is intended to serve as a comprehensive reference for all portions of a metropolitan area, from the urban core to more suburban and exurban areas (urban fringe). The Guide includes an Initiative Selector tool to aid in the selection of possible alternatives for various problems, and Freight Trip Generation (FTG) software that planners can use to identify main locations where freight is an issue based on freight trips produced and attracted. Links to access the Initiative Selector and FTG software appear in this report. The report is divided into three sections: Section 1: Urban Freight Transportation Decision-Making Process; Section 2: Overview of Public-Sector Initiatives; and Section 3: Case Studies.

Time-Dependent Effects on Parameters of Freight Demand Models: Empirical Investigation

Seven national freight origin-destination samples collected in Colombia from 1999 to 2005 were used to conduct an empirical investigation of the temporal stability of parameters of freight demand models in the short to medium term. Freight generation, freight distribution, and empty trip models were considered. To identify time-dependent effects, models were estimated with a panel formulation with time-dependent parameters and fixed time effects and then compared with the corresponding cross-sectional models. The results indicate the presence of statistically significant time-dependent effects on all freight generation models (production and attraction), freight distribution models (based on both loaded vehicle trips and commodity flows), and empty trip models. A literature review indicates that few studies are available on the temporal stability of parameters. The results show a remarkably consistent pattern in that the components of freight demand that could change faster (i.e., freight production and attraction) are those that exhibit the largest rates of parameter change. The rates of change for these models are 18.29% and 26.37%, respectively. In contrast, the freight distribution models of loaded trips were found to change less rapidly (10.50% and 1.94%, respectively, depending on the impedance function), while the tonnage distribution model exhibited only fixed time effects. The model that changes least rapidly is the empty trip model, which has a rate of change of 0.83%.

The New York City Off-Hour Delivery Program: A Business and Community-Friendly Sustainability Program

The New York City Off-Hour Delivery (NYC OHD) program is the work of a private-public-academic partnership—a collaborative effort of leading private-sector groups and companies, public-sector agencies led by the New York City Department of Transportation, and research partners led by Rensselaer Polytechnic Institute. The efforts of this partnership have induced more than 400 commercial establishments in NYC to accept OHD without supervision. The economic benefits are considerable: the carriers have reduced operational costs and parking fines by 45 percent; the receivers enjoy more reliable deliveries, enabling them to reduce inventory levels; the truck drivers have less stress, shorter work hours, and easier deliveries and parking; the delivery trucks produce 55–67 percent less emissions than they would during regular-hour deliveries, for a net reduction of 2.5 million tons of CO2 per year; and citizens’ quality of life increases as a result of reduced conflicts between delivery trucks, cars, bicycles, an...

An investigation of the effects of critical infrastructure on urban mobility in the city of Medellín

Critical infrastructure refers to the type of facilities, services, and installations (e.g., transportation, communication, energy systems) that are essential for the functioning of a community, city or country. This paper describes the findings of the research conducted to identify the transportation network critical facilities (road links) and their impacts on urban mobility for the city of Medellin, the second largest city in Colombia. This paper analyses the negative effects on travel time when a facility is disrupted or the capacity is suddenly reduced (e.g., accident, natural or manmade disaster, dedicated bike-route, maintenance, and construction). Criticality is identified following two methodologies: 1) comparing the travel time of the network users solving the user equilibrium (UE) traffic assignment problem between the base case and the disrupted network; 2) assessing the impact of the disrupted facility on the path travel times between affected origin-destinations zones.

Vehicle-Trip Estimation Models

This chapter discusses the techniques available for estimation of vehicle trips, both loaded and empty, using the output of commodity-based models. To this effect, the chapter analyses the interconnections between mode and vehicle choice and the generation of loaded trips. In doing this, the chapter establishes the importance of producing solid estimates of the average amount of cargo that they transport. The chapter critically reviews the methodologies available for estimation of empty trips, analyses the empirical evidence, and produces a set of recommendations intended to help practitioners and researchers select the most appropriate modelling techniques. The chapter ends with concluding remarks.

Freight Data Cost Elements

This report identifies the specific types of direct freight transportation cost data elements required for public investment, policy, and regulatory decision making. It describes and assesses different strategies for identifying and obtaining the needed cost data elements.

Important Aspects to Consider for Household Travel Surveys in Developing Countries

Characteristics and aspects to be considered in conducting household travel surveys (HTS) in developing countries are discussed. The main differences with the HTS conventional approach (interviewing people by telephone or mail) are highlighted. These topics are covered in the context of a case study that presents the HTS methodology used in the metropolitan area of Medellín, Colombia, in 2011 and 2012 with a sample of 20,000 face-to-face interviews. Results of the HTS are presented and analyzed for the case study. A low number of trips per inhabitant, 1.7, was found. A modal split is relevant in a city that restricts car use on the basis of license plate numbers during all weekday peak periods and that has a large number of taxis, nearly 8,000 per million inhabitants. Also shown are the difficulties that the survey interviewers experienced: planning process, accessibility to households owing to different social aspects (e.g., fear, social events, and international sporting events), and security concerns, among others. Finally, challenges for future modeling are presented.