Shashi Nambisan | University of Alabama - Tuscaloosa (original) (raw)

Papers by Shashi Nambisan

This is a discussion of the development of geographic information system (GIS) based data bases t... more This is a discussion of the development of geographic information system (GIS) based data bases that would support management systems for rail infrastructure. The application of such systems for risk and routing analyses including hazardous materials shipments are also discussed. The discussion addresses the development of GIS-based system for rail infrastructure with respect to several key elements and characteristics of a typical mainline railroad track. The paper dsescribes examples including geographic alignment, longitudinal gradient and elevation, sidings, bridges and culverts, and at-grade rail/highway crossings.

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The main objectives of this research were to review and evaluate the current automatic vehicle cl... more The main objectives of this research were to review and evaluate the current automatic vehicle classification systems and operating procedures and to design and recommend a modified AVC system that utilizes weights for improved performance. Recommendations: tubes should be used for all AVC installations as they typically had a lower frequency of missed axles/vehicles compared to piezoelectric sensors. Tubes should be installed about 6" from the edge of the inside lane marking, which would minimize the potential for stray vehicles from an adjacent lane to activate the sensors. Use of inductive loops generally would not be advantageous, except for relatively congested facilities and should be used in urban facilities that experience recurring congestion. The field test results show that the overall accuracy for all vehicles was greater than 90%, although accuracy for trucks was generally site specific. Using a different binning scheme for different sites might improve performance on individual sites. Typically, about 1 to 4% of the vehicles were missed, thus not classified by the system. Passenger vehicles are generally most affected, and proportion was typically higher when a loop was used.

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Computer-Aided Civil and Infrastructure Engineering, 1994

... 2. In areas with more concentrated populations (towns, smaller cities), population within a r... more ... 2. In areas with more concentrated populations (towns, smaller cities), population within a route corridor ProUte can be estimated to be the product of the total city population Ptotal and the ratio of the area within the corridor A,,, and the total area A,,,1 of the city:* ...

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States have been provided the authority to designate routes for the transport of highway route co... more States have been provided the authority to designate routes for the transport of highway route controlled quantity shipments of radioactive materials. The state of Nevada is currently evaluating alternative routes for such designation. This paper provides a preliminary assessment of potential system impacts of Nevada`s highway route designation for the shipment of High Level Radioactive Waste (HLRW) to the proposed geologic repository at Yucca Mountain, Nevada. A potential route being evaluated by Nevada was used to specify routing constraints for highway shipments to Yucca Mountain. Individual routes were determined for shipments from each origin using the HIGHWAY model for unconstrained and constrained routing scenarios. Results of the analysis indicate that the imposition of the routing constraint would result in increased travel times and shipment distances. These increases range from about 1.25 percent to about 80 percent. However, the magnitude of such increases is highly dependent on the geographic location of the origin.

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The purpose of this paper is to demonstrate route optimization based directly upon the minimizati... more The purpose of this paper is to demonstrate route optimization based directly upon the minimization of radiological risk as computed from local conditions. An operational impact analysis system for high level nuclear waste transport in the State of Nevada is predicated upon development and implementation of a system in which a multitude of transport policy alternatives involving high level nuclear waste shipments can be represented and analyzed. Conceptually, this involves the collection of data and the design of system inputs which can accurately characterize the policy under consideration, and the application of models that can forecast the impacts which would be expected under such policy implementation. In this fashion, issues related to high level nuclear waste transportation can be examined and the resulting consequences understood.

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The ability to deploy emergency response vehicles in an effective and timely manner is one import... more The ability to deploy emergency response vehicles in an effective and timely manner is one important measure of emergency preparedness. This paper presents an allocation of response vehicles along a transportation route utilizing travel time impedance. The allocation of the vehicles is GIS-based. The paper discusses a case study occurring in sClark County, Nevada, which illustrates potential routes for shipping hazardous materials. The software and hardware used to conduct the analyses were the Geographic Information System (GIS) ArcInfo software on a Sun MP/690. ArcInfo commands such as network analysis ALLOCATION, UNION, and BUFFER, were utilized extensively.

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Geographic Information Systems (GIS) promise significant potential to manage complex spatial data... more Geographic Information Systems (GIS) promise significant potential to manage complex spatial data often required to address transportation and air quality analysis problems. However, this potential of GIS has not been realized. The Las Vegas metropolitan area is used as a case study to demonstrate this potential. In this exploratory research paper, the relations between transportation and air quality are investigated based on traffic characteristics (vehicle miles traveled - VMT), location of refueling stations, wind patterns and air quality levels (carbon monoxide concentrations).

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Identifying and ranking high pedestrian crash zones plays a key role in developing efficient and ... more Identifying and ranking high pedestrian crash zones plays a key role in developing efficient and effective strategies to enhance pedestrian safety. This paper presents 1) a methodology to study the spatial patterns of pedestrian crashes in order to identify high pedestrian crash zones, and 2) an evaluation of methods to rank these high pedestrian crash zones. The Geographical Information Systems (GIS) based methodology to identify high pedestrian crash zones includes geocoding crash data, creating crash concentration maps, and then identifying high pedestrian crash zones. The Simple Method or the Kernel Method is generally used to generate crash concentration maps based on density values. Methods such as crash frequency, crash density, and crash rate as well as composite methods such as sum-of-the-ranks and crash score methods are used to rank the selected high pedestrian crash zones. The use of the GIS based methodology and ranking of high pedestrian crash zones is illustrated usin...

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ABSTRACT In recent years, Las Vegas metro area in Clark County, Nevada has experienced one of the... more ABSTRACT In recent years, Las Vegas metro area in Clark County, Nevada has experienced one of the highest fatal pedestrian crash rates and the pedestrian injury crash rates among urban counties with similar populations in United States. Common notions ...

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Computer modeling and analysis techniques are important tools being used to evaluate impacts asso... more Computer modeling and analysis techniques are important tools being used to evaluate impacts associated with transporting high-level radioactive waste to the proposed national repository at Yucca Mountain, Nevada. While computer models may be powerful, the availability of data sets significantly affects their usefulness. The primary objective of this paper is to discuss the development of Geographic Information System (GIS) based data sets (coverage) for evaluation of the potential mainline rail access routes to the proposed repository. Specifically the paper describes the development of GIS databases and some basic analytic tools useful for analyzing infrastructure elements. These include geographic alignment , longitudinal gradient and elevation, location and length of siding, location and characteristics of bridges and culverts, and location and characteristics of at-grade rail/highway crossings. The database allow for modelling and analyses of rail access routes identified by th...

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This study investigates factors that can be used to quantify peak hour daily pedestrian trips in ... more This study investigates factors that can be used to quantify peak hour daily pedestrian trips in urban areas in order to help estimate pedestrian trips. Various models are developed for morning peak, evening peak, evening off-peak, and combined daily peak hours depending on the type of the facilities near the high pedestrian activity locations. General linear regression modeling and other statistical methods are used to identify the significant factors. The best subset regression is used to model four different peak hour pedestrian volumes and the F-test is used to support the analysis. Various criteria are evaluated to select the best model. The model is validated and calibrated using data from the Las Vegas metropolitan area. The findings show that the daily peak hour pedestrian trips are a function of number of lanes, average annual household income and residential area proximate to the study location. Results show that the pedestrian trips are independent of the commercial area ...

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Many elements influence the pedestrian "experience" on transportation systems. Three ba... more Many elements influence the pedestrian "experience" on transportation systems. Three basic elements of a typical urban pedestrian transportation system are sidewalks, holding areas and crosswalk areas. The holding areas may be located midblock or at intersection corners and are also termed queuing areas. The crosswalk areas include pedestrian crossings of roads, rail lines, or other physical features of the transportation network. The quality of service perceived by the pedestrians is influenced by design and operational characteristics of these critical elements. Quantitative means of describing the level or quality of service include the space per pedestrian (congestion, density) and delays (waiting time per pedestrian). The level of service (LOS) and capacity analyses of sidewalks have been documented in the literature. In a similar manner the concept of capacity and level of service have been individually applied to the street corner area and the crosswalk. Thus, each ...

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Computer-Aided Civil and Infrastructure Engineering, 1994

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