Event Type: Seminar

This research explores the complex relationship between traffic
congestion and accessibility. Congestion describes both operating
conditions on transportation networks, and individual access to
opportunities. The effects of congestion variations remain relatively
understudied. Accordingly, this research proposes a conceptual
framework with three components. First, congestion can constrain
mobility and thus indirectly reduce accessibility. Second, congestion
is associated with agglomerations of activity and therefore with
increased accessibility. Finally, congestion is in part a phenomenon of
perception and behavior. Congestion and individual travel data for the
Los Angeles region are used to explore the localized spatial
relationship between congestion and accessibility. As the multifaceted
framework suggests, congestion varies substantially by neighborhood.
Some neighborhoods examined in this analysis appear to be more
“congestion adapted” than others. While individual tripmaking is to a
large degree a function of individual and household characteristics, we
construct a model to account for such characteristics. We conclude that
conventional network-based measures of congestion delays paint an
incomplete and perhaps misleading picture of the effects of traffic
congestion and call for a fresh look at both the down- and upsides of
traffic congestion.

In the United States, and increasingly the world, the automobile is
indispensable to economic and personal mobility needs. Unfortunately,
utilization of personal vehicles is currently entirely dependent on the
combustion of petroleum energy sources. Consequently, cars are a major
contributor to urban air quality problems, are the leading emitter of
greenhouse gases in car-crazy societies like California, and rely on a
diminishing supply of oil from geopolitically sensitive areas. As
global demand for mobility continues to increase, new energy sources and
new vehicle powertrains must be developed and commercialized that can
both appeal to consumers and mitigate the environmental side effects of
transportation.

This presentation examines the role that mobility plays in the progress of humankind and its importance as a cornerstone of the transportation profession. I first provide an interpretation of the elements of mobility and its evolution over time before analyzing approaches to perform mobility changes and criteria for successfully implementing new transportation modes. Finally, I present an overview of the issues and challenges created by mobility in a modern complex society.

Transportation-related air pollution and energy problems are a significant issue in the U.S. and across the world. The World Health Organization estimates that urban air pollution causes 200,000 deaths per year worldwide. Sacrificing transportation needs for environmental quality is simply infeasible since transportation provides a vital wheel for economic development. How do we meet the transportation needs in the age of development without sacrificing environment and energy sustainability? Dr. Gao’s research focuses on the nexus of transportation and environment/energy systems. In this talk Dr. Gao takes a phased approach looking into the inter-relationships of the following six intermingling topics that span across transportation, air quality, and energy systems: cleanup of the legacy diesel fleet-mathematical modeling in search for cost-effective environment abatement strategies; equity and environmental justice in the clean diesel programs; truck traffic and ozone weekend effect (OWE): emphasizing the nonlinear dynamics between transportation emissions control and ozone pollution; catching the moving targets: from PM mass to PM number; and environmental impacts of biofuels.

The transportation sector contributes approximately 30% of the total energy usage, which is mostly attributed to petroleum-based products such as gasoline and diesel fuels. Significant emissions of CO_2 , a greenhouse gas linked to climate change, are attributed to the transportation sector. However, it would be difficult to imagine our modern life without motorized transportation. The more compelling fact is that though transportation is not the largest source of greenhouse gases, this sector is the fastest growing source and is difficult to control. Alternative transportation energy sources such as hybrid-electric technologies, bio-ethanol, and hydrogen fuel cells are emerging and are being broadly investigated as replacements for the
conventional internal combustion engine. However, these new alternatives are still difficult to make competitive against oil-powered engines due to availability, cost, convenience, lack of technology, and accessibility. No simple solutions are suggested on the road toward the energy efficient and greener future. One of the key strategies in improving vehicle fuel efficiency is through enhancing vehicle fuel efficiency either by enhancing the vehicle powertrain efficiency, or by using alternative fuels, or by managing the transportation system more efficiently. This presentation describes the research that is being conducted at Virginia Tech to develop energy and emission models for use in Advanced Traffic Management System (ATMS), Advanced Traveler Information System (ATIS), IntelliDrive system, and eco-drive system applications.

Transportation provides both enormous benefits and enormous costs.
Indeed, society as we know it could not exist without an extensive and
efficient transportation system. Mobility is essential for people to get to
jobs, schools, medical care, or social activities. At the same time, the
transportation system imposes significant impacts, for example traffic
accidents, air pollution, congestion and noise. Decades of research show
that the costs and benefits of transportation are not equitably distributed.
Professor Genevieve Giuliano will discuss inequities in public transit and
suggest strategies for providing more effective and equitable services.

Advances in wireless communications have significantly impacted the everyday life of individuals. This has
already had an impact in transportation – simply consider, for example, the proliferation of navigation systems,
and the problem of driver inattention due to the use of wireless devices (as addressed by the new California law
banning the use of cellular phone handsets while driving). A significant challenge to the transportation
engineering community is to harness the capabilities provided by wireless communications to move beyond
traveler “convenience” applications, to create better system operations tools to provide improved mobility. At
a fundamental level, wireless communications provides transportation engineers two critical capabilities that
offer high potential.

1. The ability to collect system status data over links as opposed to points.
2. The ability to exchange data with targeted, mobile vehicles.

This seminar will detail research and findings in three emerging transportation areas supported by wireless
communications: probe-based traffic monitoring, managed lanes, and vehicle infrastructure integration (VII).

Transportation plays a significant role in greenhouse gas emissions, accounting for approximately a third
of the United States’ CO2 inventory. In order to reduce CO2 emissions in the future, transportation policy
makers are looking to make vehicles more efficient and increasing the use of carbon-neutral alternative
fuels. In addition, CO2 emissions can be lowered by improving traffic operations, specifically through the
reduction of traffic congestion. This research examines traffic congestion and its impact on CO2
emissions using detailed energy and emission models and linking them to real-world driving patterns and
traffic conditions. It has been found that CO2 emissions can be reduced through three different strategies:
1) reducing severe congestion, allowing traffic to flow at higher speeds; 2) reducing excessively high
freeflow speeds to more moderate conditions; and 3) eliminating the acceleration/deceleration events
associated with stop-and-go traffic that exists during congested conditions. Details on several CE-CERT
research projects that directly address these strategies will be provided.

The field of engineering systems is the focus of the Engineering Systems Division (ESD), an
interdepartmental unit at MIT. Its mission is as follows:

* Transforming engineering education, research, and practice through the emerging field of engineering systems
* Preparing engineers to think systemically, lead strategically, and address the complex challenges of today’s world, for the benefit of humankind

This talk will focus on the key aspects of this vital and growing field and education initiatives
ESD has undertaken at the undergraduate and graduate levels.

The re-allocation of available roadspace to provide priority for transit is increasing at a rapid rate
worldwide. The case for re-allocation of roadspace to transit is clear where service and passenger volumes
are substantial. However at lower volumes, the need is less clear since the benefits to transit are small but
the impacts on other road traffic large. This work summarizes the major elements of a research project
aimed at defining a balanced framework for roadspace reallocation in relation to transit priority. The
framework aims to clarify the trade-offs required in developing transit priority systems in a range of
traffic circumstances and to provide a balanced allocation of road space based on the full range of impacts.
In particular, the approach focuses on people travel and not vehicle travel. It utilizes advanced traffic
micro-simulation approaches to better understand the on-road operational implications of alternative
transit priority measures and develops a social cost benefit analysis framework to comprehensively value
the benefits and costs of priority measures to transit and traffic travelers. The impacts on general road
congestion and wider environmental, economic and social impacts are considered.