Austin, TX, United States
Austin, TX, United States

Time filter

Source Type

Mamlouk M.S.,Arizona State University | Dosa M.,AgileAssets Inc. | Dosa M.,TRC Solutions Inc.
International Journal of Pavement Engineering | Year: 2014

It is hypothesised that maintenance treatments should be applied in the preventive mode before pavements display significant amounts of distress in order to be more cost-effective. The objective of this study was to verify the concept of preventive maintenance by examining the long-term effectiveness of chip seal treatment in four climatic zones in the USA using the long-term pavement performance database. Pavement sections were categorised into smooth, medium and rough pavements, based upon initial condition (IC) as indicated by the international roughness index. Pavement performance of treated and untreated sections was collectively modelled using exponential regression analysis. Effectiveness was evaluated in terms of life extension, relative benefit and benefit-cost ratio. The results showed that preventive maintenance is cost-effective. The life extension, relative benefit and benefit cost ratio were highest for sections whose IC was smooth at the time of treatment. Chip seal treatment effectiveness showed no correlation to climatic conditions or to traffic levels. © 2014 Taylor & Francis.

PubMed | AgileAssets Inc., c BasLee Engineering Solutions BES Inc. and Florida International University
Type: Journal Article | Journal: Traffic injury prevention | Year: 2016

This article aims to evaluate the safety performance of cable median barriers on freeways in Florida.The safety performance evaluation was based on the percentages of barrier and median crossovers by vehicle type, crash severity, and cable median barrier type (Trinity Cable Safety System [CASS] and Gibraltar system). Twenty-three locations with cable median barriers totaling about 101 miles were identified. Police reports of 6,524 crashes from years 2005-2010 at these locations were reviewed to verify and obtain detailed crash information. A total of 549 crashes were determined to be barrier related (i.e., crashes involving vehicles hitting the cable median barrier) and were reviewed in further detail to identify crossover crashes and the manner in which the vehicles crossed the barriers; that is, by either overriding, underriding, or penetrating the barriers.Overall, 2.6% of vehicles that hit the cable median barrier crossed the median and traversed into the opposite travel lane. Overall, 98.1% of cars and 95.5% of light trucks that hit the barrier were prevented from crossing the median. In other words, 1.9% of cars and 4.5% of light trucks that hit the barrier had crossed the median and encroached on the opposite travel lanes. There is no significant difference in the performance of cable median barrier for cars versus light trucks in terms of crossover crashes. In terms of severity, overrides were more severe compared to underrides and penetrations. The statistics showed that the CASS and Gibraltar systems performed similarly in terms of crossover crashes. However, the Gibraltar system experienced a higher proportion of penetrations compared to the CASS system. The CASS system resulted in a slightly higher percentage of moderate and minor injury crashes compared to the Gibraltar system.Cable median barriers are successful in preventing median crossover crashes; 97.4% of the cable median barrier crashes were prevented from crossing over the median. Of all of the vehicles that hit the barrier, 83.6% were either redirected or contained by the cable barrier system. Barrier crossover crashes were found to be more severe compared to barrier noncrossover crashes. In addition, overrides were found to be more severe compared to underrides and penetrations.

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.

Banerjee A.,AgileAssets Inc. | Prozzi J.A.,University of Texas at Austin
Transportation Research Record | Year: 2015

A practical approach is presented for determining permit fees for overweight (OW) trucks based on consumption of service life of highways. A mechanistic-empirical design philosophy is used to estimate deterioration of the pavement structure. The methodology uses permanent deformation, load-related fatigue damage, and roughness scores as descriptors to estimate service life consumption for flexible pavements and punchouts and roughness measures for rigid pavements. The experiment included flexible and rigid pavement sections with varying structural numbers and slab thicknesses from sections across Texas to account for climatic and geographical differences. Each pavement section was simulated under different loading conditions reflecting the full spectrum of axle weights characteristic of single, tandem, tridem, and quad axles. The exercise provided the basis for developing group equivalency factors and axle load factors for individual axle groups. Axle-specific parameters enabled a modular approach toward determining gross load equivalencies for any truck category without restriction on axle weights or configuration. Consumption of service life was calculated as the additional pavement structure required to accommodate OW traffic in excess of the design truck volume while ensuring the same terminal distress condition. The cost incurred in providing the additional structure to offset the accelerated consumption was assigned to the responsible truck fleet in proportion to the marginal load equivalency over the legal gross vehicle weight and axle weight tolerances. Permit fees of 3.7¢/mi per equivalent single-axle load for flexible pavements and 2.9¢/mi per equivalent single-axle load for rigid pavements were found to be practical.

Saliminejad S.,AgileAssets Inc. | Saliminejad S.,Texas A&M University | Gharaibeh N.G.,Texas A&M University
Journal of Computing in Civil Engineering | Year: 2016

The quality of roadway condition data is critical for the accuracy of infrastructure management decision support systems and, ultimately, for the confidence in these systems. This paper presents a novel outlier detection method for roadway infrastructure condition data. By taking the spatial and temporal attributes of condition data into account, this method is able to detect outliers and differentiate them into gross and pseudo outliers. The method consists of two major steps. In the first step, homogenous clusters of neighboring roadway sections are identified so that sections within each cluster have the most homogeneous condition-versus-time deterioration patterns. In the second step, outliers within each cluster are detected and delineated into gross outliers (i.e., likely errors) and pseudo outliers (i.e., roadway sections affected by isolated local factors, causing their condition data to be dissimilar to their neighboring sections). The developed method was applied to roadway pavement in Texas. In the future, this method can be extended to other linear infrastructure systems such as pipelines and power transmission lines. © 2015 American Society of Civil Engineers.

Galenko A.,AgileAssets Inc. | Perrone E.,AgileAssets Inc. | Scheingberg T.,AgileAssets Inc.
Procedia Computer Science | Year: 2015

Many transportation agencies such as Departments of Transportation in the USA are using Asset Management Optimization models to plan their maintenance and rehabilitation projects. Currently available commercial solutions are often focused only on global asset performance/money spent aspect of the problem and do not take into account the benefits of synergy between the projects, i.e. the benefits of scheduling nearby projects in the same year in order to take advantage of fixed cost savings due to economies of scale. At the strategic level adding variables and constraints to account for these economies of scale are not practical since such models often already have millions of variables and constraints and adding anything new could reduce the performance significantly. Looking at the problem from a tactical perspective however it is possible to run an analysis on the global work plan that can improve cost savings from economies of scale with subtle changes to the originally analyzed performance. For example, in case of pavement management it is a common result to see gaps in the produced theoretical work plans along a route that would result in increased mobilizations to accomplish the plan. This results in extra costs both for the agency and road user. A common result might suggest fixing miles 1-8 and 9-10 in the one year and then fixing mile 8-9 in a subsequent year. Even if this solution provided the best performance for the money it is impractical to actually do it, it would make much more sense to simply fix entire 10 mile segment while achieving almost the same performance and saving mobilization costs which can be significant cost savings. A project coordination optimization model would analyze economies of scale problems such as these while also considering network constraints such as limited budgets and resources available within the administrative unit managing the work plan. This paper proposes an optimization model, referred to as Project Coordination model throughout the paper, that would attempt to improve an already created work plan by slightly changing the project schedules such that the adjusted plan would achieve similar performance while providing a more practical solution by maximizing economies of scale with reduced delivery and mobilization costs. The results of applying proposed model to one illustrative example and two real life work plans are presented and thoroughly analyzed. © 2015 The Authors. Published by Elsevier B.V.

Haleem K.,AgileAssets Inc. | Gan A.,Florida International University
Journal of Safety Research | Year: 2015

Introduction The Moving Ahead for Progress in the 21st Century (MAP-21) includes a separate program that supports safety improvements to reduce the number of fatalities and injuries at public highway-railroad grade crossings (HRGCs). This study identifies the significant factors affecting crash injury severity at public HRGCs in the United States. Method Crashes from 2009 through 2013 on 5,528 public HRGCs, extracted from the Federal Railroad Administration database, were used in the analysis. A comprehensive list of risk factors was explored. Examples include predictors related to geographic region of crash, geometry (e.g., area type and pavement marking type), railroad (e.g., warning device type and railroad class), traffic (e.g., train speed and vehicles annual average daily traffic "AADT"), highway user (e.g., driver age and gender), and environment (e.g., lighting and weather conditions). The study used the mixed logit model to better capture the complex highway user behavior at HRGCs. Results Female highway users were at higher risk of involvement in injuries and fatalities compared to males. Higher train speeds, very old drivers, open areas, concrete road surface types, and railroad equipment striking highway users before crash, were all found to increase the injury likelihood. On the other hand, young and middle-age drivers, non-passing of standing vehicles at HRGCs, industrial areas, and presence of warning bells were found to reduce injuries and fatalities. Conclusions The mixed logit model succeeded in identifying contributing factors of crash severity at public HRGCs and potential countermeasures to reduce both fatalities and injuries are suggested. Practical applications It is important to install warning bells at public HRGCs, especially at those with high number of injury and fatality crashes. Enforcement of traffic nearby HRGCs is necessary to prevent vehicles from overtaking of standing vehicles. © 2015 Elsevier Ltd. and National Safety Council.

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.

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.

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.

Loading AgileAssets Inc. collaborators
Loading AgileAssets Inc. collaborators