published journal article
published journal article
published journal article
published journal article
published journal article
working paper
This paper analyzes the impact of the transportation system management (TSM) program employed during the 1984 Los Angeles Summer Olympics. Two issues are examined. First, the impact of the various elements of the TSM program on transportation system performance is measured by conducting a series of traffic simulation studies. The results show that TSM was an important contributing factor in the favorable traffic conditions experienced during the Olympics. Second, the potential of employing TSM as a long-term transportation policy strategy is assessed. It is concluded that the travel behavior changes which occurred in response to the TSM program were unique and short-term. Under ordinary circumstances, incentives do not exist to induce changes of the magnitude observed during the Olympics.
Phd Dissertation
The aviation industry has sought to address the negative externality of aircraft noise using a variety of approaches, but there has been little theoretical work to date encompassing both the market implications and the social optimality of air transportation noise policy. This dissertation develops simple theoretical models to analyze the effects of noise regulation on an airline’s scheduling, aircraft ‘quietness’, and airfare choices. Monopolistic and duopolistic airline competition are modelled, and two types of noise limits are considered: maximum cumulative noise from aircraft operations and noise per aircraft operation. As expected, tighter noise limits, which reduce community exposure to noise, also cause airlines to reduce service frequency and raise fares, which hurts consumers. Welfare analysis investigates the social optimality of noise regulation, taking into account the social cost of exposing airport communities to noise damage, as well as consumer surplus and airline profit. Numerical simulations show that the type of noise limit has a significant effect on the magnitude of the first-best and second-best optimal solutions for service frequency, cumulative noise, and aircraft size and level of quietness. Furthermore, the numerical analyses suggest that under the more realistic second-best case, the cumulative noise limit might be a preferable policy instrument over the per-aircraft noise limit. In the monopoly’s parameter space exploration, welfare is found to be slightly higher, cumulative noise is lower, and the fare is slightly lower when the planner controls cumulative noise rather than per-aircraft noise. In the duopoly case, when the per-aircraft limit yields greater welfare than the cumulative limit, the per-aircraft limit offers only modest welfare gains above the levels achieved with the cumulative limit. But when the cumulative limit yields greater welfare than the per-aircraft limit, the cumulative limit offers substantial welfare gains above the levels achieved with the per-aircraft limit. The effects of noise taxation and the optimal level of noise taxes are also investigated with the duopoly model; the analysis shows equivalence between noise taxation and the cumulative noise limit.
conference paper
conference paper
All vehicles must follow the rules that govern traffic behavior, regardless of whether the vehicles are human-driven or Connected, Autonomous Vehicles (CAVs). Road signs indicate locally active rules, such as speed limits and requirements to yield or stop. Recent research has demonstrated attacks, such as adding stickers or dark patches to signs, that cause CAV sign misinterpretation, resulting in potential safety issues. Humans can see and potentially defend against these attacks. But humans can not detect what they can not observe. We have developed the first physical-world attack against CAV traffic sign recognition systems that is invisible to humans. Utilizing Infrared Laser Reflection (ILR), we implement an attack that affects CAV cameras, but humans can not perceive. In this work, we formulate the threat model and requirements for an ILR-based sign perception attack. Next, we evaluate attack effectiveness against popular, CNNbased traffic sign recognition systems. We demonstrate a 100% success rate against stop and speed limit signs in our laboratory evaluation. Finally, we discuss the next steps in our research.
Phd Dissertation
Sacred places – ranging from religious to secular structures, human created or natural areas, or places with ritual, symbolic, or cultural significance – are rarely addressed by urban planners but are sources of great meaning for many communities. One reason for this neglect is the inherent difficulty in measuring the value and meaning of place for different individuals or groups. This research focused on this challenge by using ethnographic field research methods to gain an in-depth understanding of how people view and interact with sacred places in their community. The case study site of Tepoztlán is an urbanizing pueblo in central Mexico where sacred places play a significant role in daily life, rituals, and festivals and urban forms facilitate these interactions. I asked how sacred meaning was ascribed to places in Tepoztlán, how the built environment impacted behavior around these spaces, how communities preserved sacred places, and the impacts of urbanization on preservation efforts. Findings derived from 53 interviews and three months of field observations revealed five themes characteristic of sacred placemaking in Tepoztlán, including intricate patterns of neighborhood exchange, intergenerational beliefs in sacred mountains, collectivism, pedestrian oriented design, and community involvement in construction of the built environment. Indigenous placemaking is then contrasted with two top-down urban development policies that changed the character of the town and threatened sacred places and placemaking. A tourism program called Pueblos Mágicos [Magical Towns] and expansion of the Pera-Cuautla freeway have degraded and commodified sacred sites and perpetuated unequal distribution of development benefits. The research discusses how employing different views of people-environment interactions beyond dominant Western views can help planners to better understand and plan for preservation of meaningful spaces and in turn preserve and enhance community identity, culture, and self-sufficiency.