COMPARING THE OPERATIONAL EFFICIENCY OF SIGNALIZED INTERSECTIONS WITH EXCLUSIVE AND CONCURRENT PEDESTRIAN PHASE OPERATIONS CONSIDERING PEDESTRIAN NON-COMPLIANCE

Intersections are a critical location for pedestrian safety and also have a role in traffic operational efficiency. To improve pedestrian safety, the Exclusive Pedestrian Phase (EPP) was developed in the 1960s, which adds a phase entirely for pedestrian movements without any conflict with vehicles. The EPP is believed to be the safest type of pedestrian protection and has been installed in many places instead of Concurrent Pedestrian Phase (CPP). CPP allows pedestrians to cross in parallel to moving vehicles which allows conflicts between turning vehicles and pedestrians. The research hypothesis was to explore whether EPP has encouraged pedestrian non-compliance (crossing without the walk signal) and conflicting pedestrians (crossing in the direct path of a vehicle) or not and what the impact of such behavior is on vehicular intersection delay. This pedestrian behavior may lead to a less safe situation for pedestrians. The research compared 8 pairs of intersections representing both EPP and CPP operations, which were selected based on similar area type and intersection geometry. The intersections selected were in the Pittsburgh urban area with one lane approaches and simple two-phase or three-phase traffic signal operations. Pedestrian crossings were observed and classified at those intersections, which provided the number of non-compliant and conflicting pedestrian’s movements. Four of the 16 intersections with EPP, in four different land use types, were then analyzed using the traffic simulation tool Synchro. The results of the analysis revealed the impact of non-compliant crossings on intersection vehicular delay. Analysis of the intersections was done in Synchro for different cases by modifying current pedestrian behavior, which provided a comparison of intersections delays for compliant and non-compliant crossings and the conversion of operations to CPP. The research findings, based on the field observations, were that non-compliant crossings were significantly higher for all of the intersections with EPP when compared to similar CPP intersections. For these highly non-compliant EPP crossing intersections, changes in intersection delay was simulated under the condition of compliant behavior and delay was found to decrease slightly. Another case of total conflicting behavior of pedestrians with EPP was also simulated and intersection delay also increased. However, when the conversion of an intersection operation from EPP to CPP was modeled, delay decreased by more than 50%, even with a very high number of conflicting pedestrians. In summary, it was found that intersections with EPP encourages pedestrian non-compliance behavior which also increases intersection delay. Even if pedestrian behavior was altered, to be more compliant, the delays would not be changed significantly. However, when an EPP intersection is converted to CPP operations, delays decreased significantly, and intersection operations improved. This could also result in improved pedestrian safety because pedestrian crossing compliance is much higher at intersections with CPP, as revealed by the research

Stormwater Analysis and Water Quality Assessment of Urban Areas

4400011482, PIT WO 14Salt is widely used for road deicing purpose in winter, and salt application could raise stream chloride level and leads to deterioration of water quality. This study represents the first steps toward developing a comprehensive understanding of how the streams chloride levels are impacted by the salt operation. Toward this goal, this study developed a procedure for the flow path modeling of urban watersheds and applied it to two sites in Pittsburgh, PA, which are potentially susceptible to road salt application by PennDOT. The procedure was used in identifying areas contributing flows to PennDOT right-of-way, and vice versa. This study further took stream water quality samples during non-winter months for establishing baselines and during the winters of 2017 and 2018. Results show that over the non-winter months, the baseline stream chloride concentration has already exceeded criteria continuous concentration most of the time, but lies below the criteria maximum concentration of the environmental regulation. Test results on winter samples show that stream chloride concentration has risen following salt application after snow events, and has exceeded the criteria maximum concentration. The study also shows how surface model of different detail levels would affect the identified contributing areas related to target watersheds, and the importance of properly incorporating roadway features such as curves and bridges

Alignment of the CMS tracker with LHC and cosmic ray data

© CERN 2014 for the benefit of the CMS collaboration, published under the terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa Medialab srl. Any further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation and DOI.The central component of the CMS detector is the largest silicon tracker ever built. The precise alignment of this complex device is a formidable challenge, and only achievable with a significant extension of the technologies routinely used for tracking detectors in the past. This article describes the full-scale alignment procedure as it is used during LHC operations. Among the specific features of the method are the simultaneous determination of up to 200 000 alignment parameters with tracks, the measurement of individual sensor curvature parameters, the control of systematic misalignment effects, and the implementation of the whole procedure in a multi-processor environment for high execution speed. Overall, the achieved statistical accuracy on the module alignment is found to be significantly better than 10μm

The ITE 2007 Annual Meeting and Exhibit in Pittsburgh, PA, USA--Getting to the Point

This article provides an overview of the early transportation history of Pittsburgh, Pennsylvania. Water transportation was a vital part of the city\u27s early growth, since the city was located at the convergence of 2 rivers. Rail transportation came to Pittsburgh in 1852, which extended the industrial basin by joining the river transportation that brought raw materials to the factories that then shipped finished materials using the railroads. The city was also the site of a unique, if short-lived, canal system. Intra-city transportation was provided by a trolley system and several inclines that were used to move people, freight and vehicles between significant elevation changes in the river valleys and adjacent hills. Although highways were constructed through Pittsburgh beginning in the 1930s, the city still has no interstate beltway and only a limited number of interstates. Pittsburgh will be the site of the Institute of Traffic Engineers\u27 annual meeting in August 2007

The ATLAS fast tracker processor design

The extended use of tracking information at the trigger level in the LHC is crucial for the trigger and data acquisition (TDAQ) system to fulfill its task. Precise and fast tracking is important to identify specific decay products of the Higgs boson or new phenomena, as well as to distinguish the contributions coming from the many collisions that occur at every bunch crossing. However, track reconstruction is among the most demanding tasks performed by the TDAQ computing farm; in fact, complete reconstruction at full Level-1 trigger accept rate (100 kHz) is not possible. In order to overcome this limitation, the ATLAS experiment is planning the installation of a dedicated processor, the Fast Tracker (FTK), which is aimed at achieving this goal. The FTK is a pipeline of high performance electronics, based on custom and commercial devices, which is expected to reconstruct, with high resolution, the trajectories of charged-particle tracks with a transverse momentum above 1 GeV, using the ATLAS inner tracker information. Pattern recognition and the track parameter extraction are expected to be performed in roughly 100 m s, allowing all the high level trigger selections to use the tracks provided by FTK in order to build high quality and robust triggering

Description and performance of track and primary-vertex reconstruction with the CMS tracker

A description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For tbar t events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of p(T) > 0.9GeV is 94% for pseudorapidities of |η| < 0.9 and 85% for 0.9 < |η| < 2.5. The inefficiency is caused mainly by hadrons that undergo nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of p(T) = 100GeV emitted at |η| < 1.4, the resolutions are approximately 2.8% in p(T), and respectively, 10μm and 30μm in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10–12μm in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung