National Institute for Transportation and Communities

The proliferation of information technology in the transportation field has opened up opportunities for communication and analysis of the performance of transportation facilities. The Highway Capacity Manual relies on rules of thumb and small data samples to generate levels of service to assess performance, but modern detection technology gives us the opportunity to better capture the dynamism of these systems and examine their performance from many perspectives. Travelers, operations staff, and researchers can benefit from measurements that provide information such as travel time, effectiveness of signal coordination, and traffic density. In particular, inductive loop detectors show promise as a tool to collect the data necessary to generate such information. But while their use for this purpose on restricted‐access facilities is well understood, a great many challenges remain in using loop detectors to measure the performance of surface streets.

This thesis proposes 6 methods for estimating arterial travel time. Estimates are compared to simulated data visually, with input/output diagrams; and statistically, with travel times. Methods for estimating travel time are applied to aggregated data and to varying detector densities and evaluated as above. Conclusions are drawn about which method provides the best estimates, what levels of data aggregation can still provide useful information, and what the effects of detector density are on the quality of estimates....

The video begins at 0:16.

Abstract: This seminar will introduce travel models to non-modelers. It will build off the previous seminar, which introduced models in general, and discuss two primary approaches to travel modeling – four-step aggregate models and activity-based disaggregate models. The inputs, basic model methodology, and outputs of each approach will be discussed. An example of each approach will be discussed as well. The goal of the seminar is to introduce key concepts, basic differences between the two approaches, and discuss the benefits and shortcomings of each approach, with a focus on application.

Speaker Bio: Ben Stabler is a supervising planner with Parsons Brinckerhoff who specializes in planning modeling systems development. Ben has worked locally, as well as internationally, on numerous four-step and activity-based travel demand and land use modeling systems and has presented at various conferences, including TRB, the TRB Planning Applications Conference, and the Innovations in Travel Modeling conference. He is a certified GIS Professional and has worked in travel forecasting for Oregon DOT as well as PTV – the makers of VISUM and VISSIM. Ben is a member of the TRB Urban Transportation Data and Information Systems Committee (ABJ30) and is an active member of the Oregon Modeling Users Group.

The video begins at 3:30.

Abstract: We all use abstractions of reality to help understand the world around us, synthesize knowledge, and to predict the consequences of our actions. These range from ad hoc mental models to highly complex mathematical creations. In this discussion we'll examine the motivations for building formal models, with particular focus on the types of models that will be explored in this course. Several different modeling approaches will be compared, along with the strengths and limitations of each. Some important questions that builders and consumers of models should ask will be covered, as well as ideas for building more useful and informative models. A discussion on how to judge the validity of a model will round out the discussion.

Speaker Bio: Rick Donnelly has over 25 years of experience in the modeling and simulation of transportation systems, from the urban to national level. His current interests include agent-based modeling of freight and logistics, integrated land use-transportation models, and dynamic network modeling. Rick leads the travel modeling and simulation practice at Parsons Brinckerhoff, an international civil and transportation engineering consultancy. He is also a senior fellow at the University of Melbourne, where he earned his doctorate in engineering, and a visiting scholar at Los Alamos National Laboratory.