The Oregon DOT Slow-Speed Weigh-In--Motion (SWIM) Project: Final Report

Weigh-in-motion (WIM) systems have provided an effective means of data collection for pavement research and facility design, traffic monitoring, and weight enforcement for over 40 years. In weight enforcement, WIM systems have been increasingly used to screen potentially overweight vehicles. Vehicles that exceed weight limits as measured on a WIM scale are then weighed on a static scale, which is subject to accuracy standards specified by the National Institute of Standards and Technology (1998). The use of WIM for screening purposes reduces queuing at weigh stations, resulting in considerable savings for both truckers and enforcement agencies. To date, however, WIM systems have not been certified for direct applications to weight enforcement

An Evaluation of Automatic Passenger Counters: Validation, Sampling, and Statistical Inference

While automatic passenger counters (APC\u27s) offer the potential for cait effective data recovery and management, they also introduce new complications in the data recovery process. This report addresses three issues associated with the implementation of APC\u27s, based on an evaluation of the recent experiences of the Tri-County Metropolitan Transportation District of Oregon (Tri-Met). First is the issue of validation, which is concerned with both the recovery and accuracy of APC passenger data. The second issue concerns the development of a sampling methodology for APC\u27s compatible with UMTA\u27s Section 15 reporting requirements. Third is the issue of inferring system-level ridership from sample data in the presence of selective APC failures. We find that the APC\u27s are providing systematically accurate passenger counts. Analysis of the data recovered from September to November 1988 also shows that sampling was representative, based on the set of trains from which ridership data were successfully recovered. The initial selection/assignment of trains, however, was not representative. Given that APC\u27s record operating data for all bus trips comprising a train assignment, a cluster sampling method is formulated that ensures an overall random selection of bus trips via a random first stage selection of trains. Selective data recovery failures can hamper the process of inferring system-level ridership from the sample estimates. For example, when failure rates vary by bus type or time of day, inferences drawn from the sample of recovered data may over or under-represent total system ridership. In such circumstances, post hoc stratification of the sample data may be required. We outline several alternative corrections based on a-priori knowledge of the mix of bus types and schedule characteristics in the system

A Ranking of U.S. Graduate Programs in Urban Studies and Urban Affairs

A ranking of 33 Urban Studies and Urban Affairs graduate programs in the U.S. is developed from peer ratings obtained in a program survey and from citation activity reported in the Social Sciences Citation Index over the 1986-89 period. In addition, a breakdown of citations by broadly defined subject areas is presented. The survey revealed a difference between Ph.D. and MUS/MA programs in the perceived relative importance of peer evaluation and citations as rating criteria. The survey results also indicate that the degree of familiarity with other programs is lower than what has been observed in most social science disciplines

Analysis of Transit Fare Evasion in the Rose Quarter

Tri-Met collected fare evasion data for buses and MAX trains passing outbound through the Rose Quarter Monday, June 11 through Saturday, July 7. Beginning September 2001, Tri-Met’s “Fareless Square’s” free zone was extended towards the Lloyd District, with an eastern boundary of NE 14th. Prior to this, all trips between the Central Business District and Lloyd Center required a full Zone 1 fare

Route Segment Level Analysis of Bus Safety Incidents

This paper analyzes collision and non-collision incidents that occurred on TriMet’s bus system over a near two-year period. The bus route network was decomposed into stop and line haul segments, and a typology of models was estimated from segment level incident, risk exposure, and roadway feature data. The frequency of non-collision incidents – mainly slips, trips and falls – was estimated to be primarily related to associated risk exposure variables. The frequency of collision incidents was also estimated to be related to risk exposure variables, as well as a number of roadway design variables. The findings serve as an initial step in informing the safety planning process

Travel and Parking Behavior in the United States

This paper looks at the connection between the regulation of parking by cities, transit service levels, and travel and parking behavior in the United States. Travel behavior information comes from the 1990 Nationwide Personal Transportation Survey (NPTS) and the Federal Urban Mass Transportation Administration’s 1990 Section 15 Report. Data on the current state of parking programs in place in central business districts of the U.S. is identified through telephone interviews of local officials responsible for parking policies from the twenty cities identified in the NPTS. The travel behavior analyses and the data from the parking officials interviews were combined with data from the Federal Highway Administration’s Journey-to-Work data to group cities according to their parking policies, transit service, and ridership levels on a continuum of “Transit-Accommodating Cities” and “Auto-Accomodating Cities”. A key finding is that cities with interventionist parking policies, high parking prices and limited supply, frequent transit service, and a high probability that travelers will pay to park are the most likely to have high transit ridership figures

Pedestrian Infrastructure Improvements: Effects on Transit Use and Perceptions of the Pedestrian Environment in Portland\u27s Roseway Neighborhood

Over the past two years the Pedestrian Transportation (PTP) of the City of Portland has been engaged in a project to encourage walking and transit use through targeted infrastructure improvements. These improvements are intended to enhance pedestrian access to transit service by aiding street crossing and providing more amenities at bus stops. Other improvements include landscaping, sidewalks, curb extensions and ramps, and improved street lighting. One of the basic assumptions of this project is that the pedestrian environment is related to transportation choices. This report explores that assumption

Accommodation of lattice mismatch in Ge_(x)Si_(1−x)/Si superlattices

We present evidence that the critical thickness for the appearance of misfit defects in a given material and heteroepitaxial structure is not simply a function of lattice mismatch. We report substantial differences in the relaxation of mismatch stress in Ge_(0.5)Si_(0.5)/Si superlattices grown at different temperatures on (100) Si substrates. Samples have been analyzed by x‐ray diffraction, channeled Rutherford backscattering, and transmission electron microscopy. While a superlattice grown at 365 °C demonstrates a high degree of elastic strain, with a dislocation density <10^5 cm^(−2) , structures grown at higher temperatures show increasing numbers of structural defects, with densities reaching 2×10^(10) cm^(−2) at a growth temperature of 530 °C. Our results suggest that it is possible to freeze a lattice‐mismatched structure in a highly strained metastable state. Thus it is not surprising that experimentally observed critical thicknesses are rarely in agreement with those predicted by equilibrium theories

Effects of Comprehensive Plan Amendments on Interchange Traffic in Oregon

In this paper we examine the effects of amendments to local comprehensive plans on interchange performance. Plan amendments over a 15-year period in Oregon resulting in changes to industrial or commercial land use were reviewed to identify those that occurred within one mile of an interchange. Regression analysis was then performed to estimate the impact of nearby plan amendments on subsequent interchange ADT. Plan amendments were found to have a substantial ADT effect on rural interchanges, but their incidence was very limited. In urban core areas, the estimated effect of plan amendments was negligible, possibly due to interchange congestion or effective land use planning. In urban fringe areas, plan amendments were estimated to account for about 5 percent of the subsequent interchange ADT, equivalent to about two years of the design life of these facilities