Thesis (M.P.A.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 115-119).

Thesis (M.P.A.)--University of Hong Kong, 1997. / Includes bibliographical references (leaves 115-119). Also available in print.

Thesis (Ph. D. in Civil and Environmental Engineering)--University of California, Berkeley, Fall 2004. / "September 2005." Includes bibliographical references (p. 46-47). Also available online via the ITS Berkeley web site (www.its.berkeley.edu).

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ix, 123 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / From its inception, the Oregon State Highway Department and Portland's political leaders repeatedly failed to address the city's automobile traffic problems. However, in 1955 the Highway Department published a comprehensive freeway plan that anticipated new federal funding and initiated an era of unprecedented road construction in the growing city. In the early 1960s, localized opposition to the city's Interstate system failed to halt the completion of three major routes. Yet, politically savvy grassroots activists and a new generation of local leaders used the provisions of the National Environmental Policy Act and the Federal-Aid Highway Act of 1973 to successfully stop the construction of two freeways in the mid 1970s. Though favorable legislation and the efforts of local politicians were instrumental in thwarting the Highway Department's plans, this study will focus on the crucial role played by the citizens who waged an ideological battle against recalcitrant highway engineers for Portland's future. / Committee in Charge: Ellen Herman, Chair; Jeffrey Ostler; Matthew Dennis

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Roundabout installations are becoming common practice among DOTs and other local governments due to their superior safety attributes compared to other conventional at-grade intersections, especially stop-control and uncontrolled intersections. Current U.S. national guidelines for roundabout illumination recommend systematic illumination for all roundabouts. This recommendation might become a potential hindrance to desired widespread installations due to implied financial costs, especially in rural areas because the competing stop-control and uncontrolled intersections can be kept unlit. Interestingly rural roundabouts in most countries around the world are not illuminated as indicated by a recent survey of international roundabout illumination policies and standards from 45 countries. Also, review of intersection safety literature does not identify any publication that supports a systematic illumination policy of U.S. roundabouts. In fact, despite this recommendation there is no quantitative research on influence of illumination levels on nighttime safety at roundabouts and little on conventional intersections. Conversely, the literature shows a significant number of published studies which have indicated that currently recommended illumination levels on roadways can be reduced without compromising nighttime safety. This dissertation evaluates the link between roundabout crashes and different illumination levels. At the beginning of this dissertation research, there was no available repository of quantitative intersection illumination levels which could be used in highway safety research. Also, existing protocols for measurement require expensive light meters and are extremely time consuming to follow, making them impractical to use to study a large number of intersections. Consequently, this dissertation first evaluates the relationship with the best available data. The best available intersection illumination data was obtained from the Minnesota data contained in the Highway Safety Information System (HSIS). Minnesota crash and illumination data from 2003 to 2010 were analyzed. This illumination data was a qualitative description of intersection illuminating schemes and/or luminaire arrangement. Therefore, this dissertation also developed a cost-effective, accurate, and rapid method for measurement of quantitative intersection illumination data, and applied the developed protocol to a case study in Georgia. The measured intersection illumination was analyzed together with crash data obtained from GDOT for 2009 to 2014. The results of a naive analysis on the best available data indicated among other findings that the presence of lighting can provide approximately 61 percent lower total nighttime crash rate compared to the unlit condition. Also, providing illumination to the roundabout circle alone can yield about 80 percent of the benefits (55 percent reduction from unlit condition) of illuminating both the roundabout circle and approaches (66 percent reduction from unlit condition). Field test results for the camera calibration indicate that the average intersection illuminance derived from the protocol is within 4 percent difference of the actual average intersection illumination estimated from following the existing protocols. Next, despite limited roundabout data and potential issues of selection bias which could not be addressed in this dissertation, a cautious roundabout illumination specific crash modification factor was estimated with a negative binomial regression model. The model results showed that an increase of 1 lux in average roundabout illuminance will result in a 4.72 percent reduction in expected number nighttime crashes. The results of this work are useful in creating a sound framework for DOTs and other transportation agencies to determine the most appropriate level of illumination for roundabouts. This study also makes a number of significant contributions to highway safety research. First, this work is the first quantitative study on the impact of illumination on safety at roundabouts. The status-quo for highway safety research regarding the impacts of illumination had been to treat road lighting as a binary (Lit/Unlit) variable. However, even in most places without purposely-built road lighting there is usually ambient lighting from abutting facilities such as a gas stations or a store. Second, this dissertation is the first documented application of the photographic method to roundabouts. It is also the first documented application of the photographic method’s camera specific constant calibration approach to transportation field measurements. Previous documented application of the photographic method to transportation field measurements used an exposure specific calibration approach. Unlike the camera specific constant calibration approach, the exposure specific approach is rigid and field measurements must always be done at the exposure settings used in calibrating the camera. Thirdly, this work demonstrates the first developed procedure to developing uniformity (contour) plots from the photographic method. Next, this work can serve as the basis for initial efforts to create an illumination specific quantitative crash modification factor. Currently, the Highway Safety Manual is lacking in this important safety parameter. Last, but not the least this work offers procedures for collecting luminance data from the field and also documents a database of intersection illumination levels and intersection characteristics which can be used by future research.

We present a novel approach for vehicle detection and tracking in highway surveillance videos. This method incorporates well-studied computer vision and machine learning techniques to form an unsupervised system, where vehicles are automatically "learned" from video sequences. First an enhanced adaptive background mixture model is used to identify positive and negative examples. Then a video-specific classifier is trained with these examples. Both the background model and the trained classifier are used in conjunction to detect vehicles in a frame. Tracking is achieved by a simplified multi-hypotheses approach. An over-complete set of tracks is created considering every observation within a time interval. As needed hypothesized detections are generated to force continuous tracks. Finally, a scoring function is used to separate the valid tracks in the over-complete set. The proposed detection and tracking algorithm is tested in a challenging application; vehicle counting. Our method achieved very accurate results in three traffic surveillance videos that are significantly different in terms of view-point, quality and clutter. / text

Temporary Concrete Traffic Barriers (TCTBs) are essential in order to protect the traveling public and highway construction crews from accidents due to driver misfortune or negligence. In order for TCTBs to be installed, however, they must be successfully crash tested. Barrier height and drainage open space are key characteristics that influence this crash test rating. This is because an increase in height will insure that a vehicle will not over-top the barrier and a decrease in drainage open space will result in greater barrier mass, which will in turn resist larger impact forces. The factors that increase the crash worthiness of a barrier, however, lead to poor hydraulic performance. This then becomes a concern if barriers are placed in areas where they may adversely impact the local floodplain elevation. The objective of this research is the development of a hydraulic rating curve that describes the relationship between upstream energy head and the flow rate passing the barrier. To accomplish this objective, a three parameter model with three unknown coefficient terms was utilized. The model was then fit to experimentally obtained data, and a rating curve was developed. In addition, the effects of downstream submergence and clogging of the drainage opening, with respect to the rating curve, was also analyzed. Finally, a method for using this information in the hydraulic modeling software HEC-RAS was developed. / text