Phoenix, AZ, United States
Phoenix, AZ, United States

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Shields D.J.,Kimley Horn and Associates Inc.
Journal - American Water Works Association | Year: 2012

Previous studies have identified water meter inaccuracy at low flow rates as a significant source of nonrevenue flow for water systems. However, a lack of available data makes it difficult to include low-flow accuracy and accuracy degradation in meter replacement plans. This article examines results from an extensive accuracy program carried out at the Utah Water Research Laboratory on small water meters over a wide range of flow rates and at various levels of throughput. The article compares expected apparent losses of different types of water meters based on a flow profile and expected daily use for the state of California. By including an average composite charging rate, the method developed in this study can determine the meter replacement payback period for different meter types. The analysis contained in this article is intended as a guide to assist utility managers when developing meter replacement plans.


Johnson J.,Kimley Horn and Associates Inc. | Chowdhury M.,Clemson University | He Y.,Clemson University | Taiber J.,Clemson University
Transportation Research Part C: Emerging Technologies | Year: 2013

Due to the tremendous political, economical, and environmental pressures the transportation sector is facing, the United States finds itself devoting more energy to innovative solutions such as electric vehicle (EV) technologies. The purpose of this study was to analyze how utilizing real-time information dissemination transferring capabilities to vehicles, as envisioned in the " connected vehicle" system, could effectively facilitate the EV charging process at fast-charging stations (CS). By simulating a traffic network of EVs in MATLAB, it was found that the total time due to the battery charging process was optimized at both the individual EV and the entire network levels for EVs that were able to use connected vehicle communications. As a result of this optimization, the improvement of two vehicle parameters, extra travel time due to charging and time spent in the CS queue, as well as two CS parameters, queue length and total energy output, were measured. Through connected vehicle technologies, the average extra travel time due to charging and the average time spent in the CS queue were significantly reduced, resulting in benefits at both a network level and individual vehicle level. However, as a tradeoff of the optimization, the charging infrastructure may need to be upgraded in order to increase the capacity of the network. Most importantly, the benefits of connected vehicle systems were found to steadily increase as the market penetration level of EVs also increased in the varying simulation scenarios. © 2012 Elsevier Ltd.


Gartner A.,Kimley Horn and Associates Inc. | Douglas E.P.,University of Florida | Dolan C.W.,University of Wyoming | Hamilton H.R.,University of Florida
Journal of Composites for Construction | Year: 2011

This paper presents the development of a test method that can be used to test the bond capacity of carbon fiber-reinforced polymer (CFRP) composites bonded to concrete. The rationale for the selection of the test method is described along with the results of the experimental work used to refine the test configuration and procedures. The research objectives were to develop a test method that (1) can be used to evaluate the durability of the FRP-concrete bond (adhesion failure mode); (2) facilitate multiple replicate for statistical validation; (3) is simple to conduct; and (4) provides comparative results that are easy to interpret. The method utilizes a small concrete beam modeled after the modulus of rupture test, which is typically used to measure concrete tensile strength. A number of small beam sizes and loading configurations were considered during the investigation. The final recommended specimen configuration is 4×4×14 in. (100 mm×100 mm×356 mm) beam with a half-depth saw cut at midspan. A 1 in. (25 mm) wide by 8 in. (203 mm) long CFRP strip is applied to the tension face of the beam over the saw cut. The specimen is loaded until failure with a single concentrated load at midspan over a 12 in. (305 mm) span. For durability testing, samples are prepared with the same materials and exposed to the desired accelerated conditioning protocol. Companion unexposed samples are also tested and the relative decrease in capacity is reported as the load to failure of the exposed specimen to that of the control specimen. © 2011 ASCE.


Wu X.,500 Pillsbury Drive S.E. | Liu H.X.,500 Pillsbury Drive S.E. | Gettman D.,Kimley Horn and Associates Inc.
Transportation Research Part C: Emerging Technologies | Year: 2010

Conceptually, an oversaturated traffic intersection is defined as one where traffic demand exceeds the capacity. Such a definition, however, cannot be applied directly to identify oversaturated intersections because measuring traffic demand under congested conditions is not an easy task, particularly with fixed-location sensors. In this paper, we circumvent this issue by quantifying the detrimental effects of oversaturation on signal operations, both temporally and spatially. The detrimental effect is characterized temporally by a residual queue at the end of a cycle, which will require a portion of green time in the next cycle; or spatially by a spill-over from downstream traffic whereby usable green time is reduced because of the downstream blockage. The oversaturation severity index (OSI), in either the temporal dimension (T-OSI) or the spatial dimension (S-OSI) can then be measured using high-resolution traffic signal data by calculating the ratio between the unusable green time due to detrimental effects and the total available green time in a cycle. To quantify the T-OSI, in this paper, we adopt a shockwave-based queue estimation algorithm to estimate the residual queue length. S-OSI can be identified by a phenomenon denoted as " Queue-Over-Detector (QOD)" , which is the condition when high occupancy on a detector is caused by downstream congestion. We believe that the persistence duration and the spatial extent with OSI greater than zero provide an important indicator for measuring traffic network performance so that corresponding congestion mitigation strategies can be prepared. The proposed algorithms for identifying oversaturated intersections and quantifying the oversaturation severity index have been field-tested using traffic signal data from a major arterial in the Twin Cities of Minnesota. © 2010 Elsevier Ltd.


Walnum N.,Kimley Horn and Associates Inc.
Automated People Movers and Transit Systems 2013: Half a Century of Automated Transit - Past, Present, and Future - Proceedings of the 14th International Conference | Year: 2013

The PHX Sky Train will serve passengers getting to and from the Phoenix Sky Harbor International Airport (Airport) from the City's light rail system, between terminals, parking facilities and eventually to the Rental Car Center west of the Airport. To do this, the train guideway must cross over and under taxiways, through Runway Protection Zones (RPZs), across railroads, pass over existing pedestrian bridges, and connect to existing terminal buildings through a very congested and narrow corridor. Finding the right guideway alignment and station locations to best serve Sky Train users, while minimizing costs and maximizing ridership, was an extremely challenging process. This paper reviews some of the constraints and alternatives that were considered during the guideway alignment development, including preliminary plans to tunnel under Terminal 4 and Terminal 3 and why the Airport ultimately decided to cross over Taxiway R instead. The paper discusses the interesting challenges associated with determining the best alignment for the PHX Sky Train, including the crossing of Union Pacific Railroad (UPRR), utilizing the SR-153 roadway corridor, impacts and enhancements to the East Economy Parking, crossing Taxiways R, S, and T, and connection points to each of the Terminals. The alignment development was heavily influenced by the Airport's desire to increase ridership, remove buses and traffic from the airport roadways to relieve congestion, and to provide excellent customer service. The paper concludes with a brief look ahead to the upcoming design challenges associated with extending the train alignment to the Rental Car Center, which will be the largest driver of passenger activity on the system. © 2913 American Society of Civil Engineers.


Lott J.S.,Kimley Horn and Associates Inc.
Automated People Movers and Transit Systems 2013: Half a Century of Automated Transit - Past, Present, and Future - Proceedings of the 14th International Conference | Year: 2013

The paper examines the prospect of applying automated transit circulator systems for the "last mile" conveyance of passengers between a high-speed rail station and their destination in the surrounding urban district. The characteristics of high-speed rail stations are discussed with respect to their scale, urban context and ridership demand patterns, and the capacity requirements for automated systems to serve in the "last mile" function. Current project work on the Texas DOT Intercity Passenger Rail Ridership Study is referenced, and a discussion of the simulation and analysis methodologies being used in the study are compared to similar methodologies previously applied to study automated guideway transit connector systems in airports. The paper concludes with an assessment of the suitability of conceptual aerial guideway automated transit systems in conjunction with high speed rail stations for each of the main classifications of automated transit technologies. © 2913 American Society of Civil Engineers.


Gulliver B.,Kimley Horn and Associates Inc.
International Conference on Transportation and Development 2016: Projects and Practices for Prosperity - Proceedings of the 2016 International Conference on Transportation and Development | Year: 2016

The commercial spaceport business continues to evolve as new commercial spaceports in the United States receive their FAA launch site operator licenses. The current mix of commercial spaceports provide a range of launch opportunities and can support a myriad of commercial space missions. Current spaceports include those capable of supporting horizontal launch, vertical launch, or both. With launch locations either on the coast or inland, each spaceport has certain limitations on the types of missions they may be able to support, whether they are suborbital or orbital in nature. The author has been a leading consultant on numerous commercial spaceports including those in Florida, Virginia, Texas, Hawaii, and the United Kingdom. This paper will provide a historical context for commercial spaceports to review where spaceports are now and what will come next. © ASCE.


Lahon D.,Kimley Horn and Associates Inc.
Institute of Transportation Engineers Annual Meeting and Exhibit 2012 | Year: 2012

As part of the "METRO Solutions" program, we evaluated the impact of three Light Rail Transit (LRT) lines on traffic operations in downtown Houston. We modeled the interactions of automobile and bus traffic with three LRT lines (Red Line, East End Line, and Southeast Line). We performed traffic projections to approximate future year traffic demands, applied a trip reduction factor to account for the Downtown transit facilities, and analyzed AM and PM peak hours for future year conditions for the "with interline" and "without interline" scenarios. In the "with interline" scenario, the East End trains merge onto the Red Line alignment to reach the intermodal terminal while Southeast trains continue all the way to the western terminus. In the "without interline" scenario both East End and Southeast trains travel to the western terminus. Some of the key factors identified in this analysis to efficiently operate the LRT system include train control system, signaling coordination, effective geometric design, increasing driver awareness, effective signal timing, effective driveway control, effective signage, preemption locations, and integration between the traffic signal system and the train signal system. We recommended deploying a train control system that would modulate station dwell times as a means of continuously optimizing train headways on each of the three routes that pass through the study area. This also minimizes clustering of trains and degradation of intersection level of service. Our traffic models and analysis have served as useful tools for stakeholders to further understand the impact of the downtown LRT system.


Washburn S.S.,University of Florida | Cruz-Casas C.O.,Kimley Horn and Associates Inc.
Computer-Aided Civil and Infrastructure Engineering | Year: 2010

The most common method used for the analysis of signalized intersections in the United States is contained in the Highway Capacity Manual (HCM). In this method, the base saturation flow rate of the signalized intersection is defined in units of passenger cars per hour green per lane (pc/hg/ln). To account for the presence of large trucks in the traffic stream, the HCM includes a Passenger Car Equivalency (PCE) value. In the current edition of the HCM, a PCE value of 2.0 is applied for all large trucks, with no distinction between different sizes of trucks. The HCM also recommends a single value of 2.0 seconds for startup lost time, regardless of queue composition. Many transportation professionals have questioned the validity of the PCE value and startup lost time recommended by the HCM. They are concerned that the impact of trucks at signalized intersections is being underestimated. If this is the case, then capacity is being overestimated and intersections are not being adequately designed. The objective of this study was to identify appropriate truck PCE values and a relationship for startup lost time as a function of truck percentage in the traffic stream. To accomplish this objective, a custom simulation tool was developed based on the modified Pitt car-following model, calibrated with field data, and applied to a comprehensive experimental design. The PCE values determined from this study are 1.8, 2.2, and 2.8 for small, medium, and large trucks, respectively. A model for estimating startup lost time based on the same small, medium, and large truck classifications was also developed. © 2010 Computer-Aided Civil and Infrastructure Engineering.


Capelli J.A.,Kimley Horn and Associates Inc. | Fernandez W.,Miami Dade Metropolitan Planning Organization
Automated People Movers and Automated Transit Systems 2016: Innovation in a Rapidly Urbanizing World - Proceedings of the 15th International Conference | Year: 2016

The Miami Metromover is a free automated people mover system operated by Miami-Dade Transit serving Downtown Miami's Central Business District and surrounding neighborhoods. Due to the dramatic increase in the Miami Metromover ridership over the last decade and the recent development in key areas of downtown Miami, feasible options to connect future Metromover passengers to a new urban downtown lifestyle through an expanded Metromover System are needed. This paper summarizes the initiative to quickly and proficiently assess the feasibility of expanding the Metromover System to connect the underserved markets in downtown Miami while maintaining an efficient operation of the existing system. The project initiative was developed by the Miami-Dade Metropolitan Planning Organization in coordination with Miami-Dade Transit and other partner agencies. During the study, options for system expansion were conceptualized and evaluated to provide greater system accessibility to Metromover users and improve system efficiency within the downtown area. Major elements of the study included data collection, passenger sampling survey, development of a Metromover Expansion Master Plan, and identification of a preferred concept through a variety of quantitative and qualitative measures. As part of the refinement process estimated capital costs and operations and maintenance costs for the project were developed. © ASCE.

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