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Anastasopoulos P.C.,Purdue University | Labi S.,Purdue University | Bhargava A.,AgileAssets Inc. | Bordat C.,RATP France | Mannering F.L.,Purdue University
Journal of Construction Engineering and Management | Year: 2010

A common problem at state transportation agencies is the inability to complete projects within the original scope of work. Change orders, which are contractual documents issued to accommodate the additional work in a contract, are generally due to root causes such as design errors, unexpected site conditions, and weather conditions, and intermediate causes such as bidding characteristics. At the preaward phase of project management, an improved understanding of the factors that are associated with change orders will be of value and also can serve as a basis for taking steps to reduce concomitant contractual aberrations such as time delay and cost overruns. Recognizing that the occurrence of change orders is a count variable, this paper analyzes the frequency of change orders using a variety of count-modeling methods including the negative binomial, Poisson, zero-inflated negative binomial, and zero-inflated Poisson. Using 5 years of contract data from Indiana highway projects, appropriate models are estimated to assess the influence of project type, contract type, project duration, and project cost on the frequency of change orders. © 2010 ASCE. Source


Anastasopoulos P.Ch.,AgileAssets Inc. | Florax R.J.G.M.,Purdue University | Florax R.J.G.M.,VU University Amsterdam | Labi S.,Purdue University | Karlaftis M.G.,National Technical University of Athens
Transportation Research Part A: Policy and Practice | Year: 2010

Highway agencies around the world strive to improve practices for infrastructure maintenance and rehabilitation, using project delivery policies that range from total 'in-house' responsibility to complete privatization, with a number of flexible contracting policies such as performance-based contracting, variants of design-build-maintain, and lane rentals among others between these two extremes. In this paper, we present a methodology that duly accounts for underlying spatial effects and estimates the expected cost savings of innovative contracting policies for highway maintenance and rehabilitation relative to in-house execution of these activities. Spatial econometric modeling is used to analyze highway contract data from 49 countries. We also investigate the marginal effects of key explanatory variables on contract cost savings using spatial multipliers. Our findings show that there are significant relationships between cost savings and contract characteristics, and that there is an apparent direct relationship between the average cost savings of contracts in a country and contract average cost savings and contract sizes in neighboring countries. © 2009 Elsevier Ltd. All rights reserved. Source


Bhargava A.,AgileAssets Inc. | Anastasopoulos P.C.,Purdue University | Labi S.,Purdue University | Sinha K.C.,Purdue University | Mannering F.L.,Purdue University
Journal of Construction Engineering and Management | Year: 2010

Construction cost overrun and time overrun (delay) are a significant problem in highway-construction project delivery. Previous research studies have provided insight into the factors that affect overruns; however the findings may have been limited because they do not explicitly consider the simultaneous relationship between cost and time overruns. In this paper, we use data from Indiana highway projects to provide empirical evidence that a simultaneous relationship exists between cost and time overruns and that analysis of these two contractual outputs need to take due cognizance of such simultaneity. Using the three-stage least-squares technique, we identify a number of factors that significantly affect cost overrun and time overrun and we show how the effect of these variables vary by attributes such as project type and results of the bidding process. The models developed in this paper can help agencies enhance the estimation of the expected overruns of final cost and the delay in completion time for their planned projects. © 2010 ASCE. Source


Harvey J.,University of California at Davis | Wang T.,AgileAssets Inc. | Lea J.,University of California at Davis
Green Energy and Technology | Year: 2014

Environmental life cycle assessment (LCA) is a method developed in the 1960s for identifying environmental objectives, defining the system to be analyzed, quantifying environmentally important inputs and outputs to the system over a life cycle, and assessing the impacts. The application of LCA to pavements is a relatively new development. Pavement management systems (PMS) have been developed and implemented since the 1970s to manage pavement network asset inventories, collect condition data, predict performance for various management decisions and report the results to support decision-making needed to meet performance and cost objectives. This chapter discusses the relationship between LCA and PMS and benefits of integrating LCA into PMS. An example is provided for the objective of reducing greenhouse gas emissions on a state highway network. Gaps in implementation are identified, and recommendations are made for future work. © Springer-Verlag Berlin Heidelberg 2014. Source


Haleem K.,AgileAssets Inc. | Alluri P.,Florida International University | Gan A.,Florida International University
Accident Analysis and Prevention | Year: 2015

This study identifies and compares the significant factors affecting pedestrian crash injury severity at signalized and unsignalized intersections. The factors explored include geometric predictors (e.g., presence and type of crosswalk and presence of pedestrian refuge area), traffic predictors (e.g., annual average daily traffic (AADT), speed limit, and percentage of trucks), road user variables (e.g., pedestrian age and pedestrian maneuver before crash), environmental predictors (e.g., weather and lighting conditions), and vehicle-related predictors (e.g., vehicle type). The analysis was conducted using the mixed logit model, which allows the parameter estimates to randomly vary across the observations. The study used three years of pedestrian crash data from Florida. Police reports were reviewed in detail to have a better understanding of how each pedestrian crash occurred. Additionally, information that is unavailable in the crash records, such as at-fault road user and pedestrian maneuver, was collected. At signalized intersections, higher AADT, speed limit, and percentage of trucks; very old pedestrians; at-fault pedestrians; rainy weather; and dark lighting condition were associated with higher pedestrian severity risk. For example, a one-percent higher truck percentage increases the probability of severe injuries by 1.37%. A one-mile-per-hour higher speed limit increases the probability of severe injuries by 1.22%. At unsignalized intersections, pedestrian walking along roadway, middle and very old pedestrians, at-fault pedestrians, vans, dark lighting condition, and higher speed limit were associated with higher pedestrian severity risk. On the other hand, standard crosswalks were associated with 1.36% reduction in pedestrian severe injuries. Several countermeasures to reduce pedestrian injury severity are recommended. © 2015 Elsevier Ltd. All rights reserved. Source

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