Most specifications for ready-mix concrete (RMC) limit mixing time to 90 minutes and/or truck drum revolution counts (DRC) to 300 before discharge. These specifications have been in place for many years with the objective of ensuring the quality and performance of the finished concrete product. However, limited research has been...
Highway capacity has traditionally been treated as deterministic. In reality, however, capacity can vary from time to time and location to location due to inclement weather, various driving behavior, traffic incident, bottleneck and workzone. This thesis aims to characterize the stochastic variations of highway capacity, and explore its applications.
The...
A right-hook crash is a bicycle-motor vehicle crash between a right-turning motor vehicle and an adjacent through-moving bicycle. This study focuses on right-hook crashes that occur during the latter stage of the circular green indication at signalized intersections with shared right-turn and through lanes. The overall objective was to evaluate...
This thesis provides a comparison of advanced econometric frameworks to account for unobserved factors in crash reported data (also referred to as unobserved heterogeneity) while identifying contributing factors by roadway classification for heavy vehicle injury severity and crash rates. The presented thesis provides two manuscripts that expand the literature regarding...
Flexible pavements consist of multilayers, which form the pavement structures. Since the strength of the bond at interface between layers plays a significant role in improving the structural integri-ty and the performance of pavement structures, tack coat materials and methods used for their application during construction are important in providing...
CSS-1H is the most commonly used slow-setting emulsion grade in Oregon. “New” engineered emulsions were recently developed in Oregon to reduce tracking, the pick-up of tack coats by construction vehicle tires during construction activities, and increase interlayer shear strength (ISS), the amount of adhesive bond present between layers of asphalt...
Concrete is the most widely used construction material in the world. When constructing large concrete structures, concrete may have to be placed in multiple lifts. In these cases, fresh concrete is placed on hardened concrete. The interface that is formed between these two lifts of concrete is known as a...
Wheeled mobility devices (WhMD) pose unique safety risks to users while riding public transportation. Unsecured or improperly secured WhMDs create safety concerns for other transit riders and operators. Tests using accelerometers and visual observations were conducted to understand how WhMD orientation and securement in articulated buses, streetcars, and light rail...
Red Light Running (RLR) is a safety hazard at signalized intersections in Oregon and throughout the United States. Various methods of mitigating factors contributing to RLR have been implemented but few protect against a conflict when a vehicles runs a red light. Additionally, current prediction algorithms are complicated; there is...
Pedestrian distraction at roadway crossings has been correlated with a higher risk of pedestrian-vehicle collisions due to the pedestrian's cognitive, visual, and motor attention being drawn to a wide variety of secondary tasks.
This study is different from previous field studies of pedestrian midblock crossings in that the geometric layout...