Tariq Usman Saeed

Predicting Cost Escalation Pathways and Deviation Severities of Infrastructure Projects Using Risk-Based Econometric Models and Monte Carlo Simulation

In the past decade, infrastructure-related legislation in the United States has consistently emphasized the need to measure the variation associated with infrastructure project cost estimates. Such cost variability is best viewed from the perspective of the project development phases and how the project cost estimate changes as it evolves across these phases. The article first identifies a few gaps in the cost overrun literature. Then it introduces a methodology that uses risk-based multinomial models and Monte Carlo simulation involving random draws to predict the probability that a project will follow a particular cost escalation pathway across its development phases and that it will incur a given level of cost deviation severity. The article then uses historical data to demonstrate how infrastructure agencies could apply the proposed methodology. Statistical models are developed to estimate the probability that a highway project will follow any specific cost escalation pathway and ultimately, a given direction and severity of cost deviation. The case study results provided some interesting insights. For a given highway functional class, larger project sizes are associated with lower probability of underestimating the final cost; however, such a trend is not exhibited by very large projects total cost exceeding

Performance Evaluation and Life Prediction of Highway Concrete Bridge Superstructure across Design Types

30M. For a given project size, higher class roads were generally observed to have a lower probability of underestimating the final cost, compared to lower class roads and this gap in probability narrows as the project size increases. It was determined that a projects most likely pathway of cost escalation is not a guarantee that it will yield any particular direction of cost deviation. The case study results also confirmed the findings of a few past studies that the probabilities of cost escalation pathways and the cost overruns differ significantly across highway districts, and attributed this to differences in administrative culture and work practices across the districts. Infrastructure managers can use the developed methodology to identify which projects are likely to experience a particular pathway of cost escalation, the direction and severity of cost deviation, and to develop more realistic project contingency estimates.

Pavement Repair Marginal Costs: Accounting for Heterogeneity Using Random-Parameters Regression

AbstractManagers of highway bridge infrastructure constantly seek to improve their predictions of the physical performance of their facilities at any future time and also to identify the influentia...

Estimation of rest periods for newly constructed/reconstructed pavements

AbstractHighway agencies seek to establish road user cost responsibilities, in the form of marginal costs associated with the maintenance and rehabilitation (M&R) of their existing infrastructure, ...

Safety impacts of pavement surface roughness at two-lane and multi-lane highways: accounting for heterogeneity and seemingly unrelated correlation across crash severities

AbstractNewly-constructed and reconstructed highway pavements under the effect of traffic loading and climatic severity deteriorate progressively and need preservation intervention after a certain number of years following their construction. In the literature, the term ‘rest period’ has been used to refer to the number of years that elapse between the construction completion to the application of first major repair activity. The rest period is a critical piece of information that agencies use to not only plan and budget for the first major repair activity but also to develop more confidently, their life-cycle activity schedules for life cycle costing, work programming, and long-term plans. However, the literature lacks established procedures for predicting rest periods on the basis of pavement performance thresholds. In the absence of such resources, highway agencies rely mostly on expert opinion for establishing the rest periods for their pavement sections. In addressing this issue, this paper presents ...

Methodology for Probabilistic Modeling of Highway Bridge Infrastructure Condition: Accounting for Improvement Effectiveness and Incorporating Random Effects

ABSTRACT Highway agencies continue to show interest in measuring pavement condition effects on safety. This paper estimates univariate negative binomial (UNB) and random-parameters seemingly-unrelated negative binomial (RPSUNB) regression models. The latter account for unobserved heterogeneity and correlation in crash frequencies across the crash severity levels. The analysis was carried out for two-lane and multi-lane highways, and the results suggest that at the latter, the pavement condition generally has a far more significant safety impact compared to the former. This could be due to risk compensation effects where drivers offset the safety hazard associated with inherently less safe situations by driving more carefully. It was determined that compared to UNB, RPSUNB models have superior efficacy in addressing seemingly unrelated correlations among the crash severity levels.

Addressing the Local-Road VMT Estimation Problem Using Spatial Interpolation Techniques

AbstractThe peculiar nature of bridge infrastructure condition data persistently poses challenges in predicting bridge component deterioration that necessitate the continued investigation of probab...

Estimation of Routine Maintenance Expenditures for Highway Pavement Segments: Accounting for Heterogeneity Using Random-Effects Models

AbstractVehicle miles of travel (VMT) data have a wide range of applications in highway agency business processes. However, at all administrative levels, highway agencies continue to be stymied by ...

Floodplain Mapping Using HEC-RAS and ArcGIS: A Case Study of Kabul River

AbstractA significant portion of highway infrastructure life-cycle costs can be attributed to maintenance expenditures, particularly in the later years of an infrastructure’s life. These expenditur...