Carlos M. Chang

Systematic statistical approach to populate missing performance data in pavement management systems

AbstractTransportation agencies use pavement management systems (PMS) for their maintenance and rehabilitation planning, programming, and budgeting. PMS is used to make decisions regarding when maintenance and rehabilitation should be applied. To support these decisions, it is important to have reliable data on pavement conditions and accurate performance models for predicting pavement condition. The data on pavement condition typically come from regular field surveys resulting in distress, condition, and ride scores. PMS data sets are often incomplete (for some locations and some years) as a result of operational limitations reducing the predictive power of the performance models. Model-free and model-based replacement techniques for estimating missing data points have been designed and successfully used in other application areas like statistics, economics, marketing, medicine, psychometrics, and political science. It is therefore reasonable to apply these methods to the PMS databases. Statistical techn...

Fair Division Transportation Allocation Model for Funding Prioritization

AbstractDue to the increasing population and limited funding for maintenance and construction, the efficiency of the transportation network system in the U.S. is being challenged by a potential crisis that endangers the economic growth of the nation and the quality of life of the people. Although funding allocation can be approached using different methods, it is difficult to reach consensus on the criteria used to distribute limited funds among competing needs. Conventional funding allocation methods use weighted formulas based on population and other criteria. However, formula-based funding allocation methods may lead to the public’s disagreement if funding allocation final decisions are not perceived as fair or equitable by all agencies. A fair division transportation allocation model (FDTAM) is proposed as an alternative to fairly distribute limited funds among the agencies competing for funding. The FDTAM aims to maximize the participants’ project desirability and to minimize total envy due to budget...

Integrating Guardrail System Preservation Policies into Asset Management Practices

Asset management provides a strategic framework for infrastructure systems and focuses on getting the most out of their performance with the available resources. To determine future budget needs, highway agencies must have the necessary data and analytical tools with which to predict the performance of highway assets over time. Currently, transportation asset management systems are at different maturity levels. Pavement and bridges are considered the big ticket of all highway assets, but the preservation of signs, signals, lighting, guardrails, and pavement markings is also crucial to protect road users. Despite its importance, one of the safety assets with fewer asset management analytical tools is guardrail systems. Transportation agencies typically replace or repair guardrails that have endured major damage from car crashes. To implement a proactive preservation program, in agreement with transportation asset management practices, various parameters must be known. These parameters include inventory information, current guardrail condition, and performance models to forecast changes in the guardrail system condition over time. This paper describes a performance-based model with an analytical method to formulate a proactive preservation program for guardrail systems. The model was developed from inventory data and predicts changes in the guardrail system condition over time. A case study estimates the annual agency costs and backlogged costs over a 10-year analysis period. This model can be integrated into an asset management system to facilitate the formulation of preservation programs for guardrail systems at the strategic level.

Vulnerable User Road Safety Enhancements for Transportation Asset Management

The purpose of transportation asset management (TAM) is to provide a required level of service of transportation infrastructure assets in the most cost-effective manner, while providing safe transportation options to all users. In urban areas these users include not only motorized vehicles, but also pedestrians, cyclists, aging users and well as users with disabilities. It is crucial that the TAM decision-making incorporates the needs of all users using the transportation infrastructure, in order to promote transportation options that foster healthy life-style, improve quality of life as well as reduce greenhouse gas emissions and inequity. This paper discusses how maintenance decisions for roadway assets are influenced by traffic safety information including vehicle crash data and road safety audits. Preventive maintenance, rehabilitation, and reconstruction events throughout the asset life-cycle are paired with safety improvements on high-risk road segments or crossings to provide a transportation network that is accessible and safe for vulnerable road users.