Conditions and Performance Chapter Listing

Conditions and Performance Home Page

Introduction

Summary

Economics-Based Approach to Transportation Investments

Highway Investment Requirements

Bridge Investment Requirements

Combined Highway and Bridge Investment Requirements

Transit Investment Requirements

Background

The methods and assumptions used to estimate future highway, bridge and transit investment requirements are continuously evolving. Since the beginning of the highway report series in 1968, innovations in analytical techniques, new empirical evidence and changes in transportation planning objectives have combined to encourage the development of improved data and analytical techniques.

Estimates of future highway investment requirements, as reported in the 1968 National Highway Needs Report to Congress, began as a "wish list" of State highway "needs." Early in the 1970s the focus changed from system expansion to management of the existing system. National engineering standards were defined and applied in the identification of system deficiencies. By the end of the decade, a comprehensive database, the HPMS, had been developed to monitor system conditions and performance.

By the early 1980s a sophisticated simulation model, the HPMS Analytical Process (AP), was available to evaluate the impact of alternative investment strategies on system conditions and performance. This procedure is founded on engineering principles: engineering standards define which system attributes are considered deficient and the improvement option "packages" assigned to potentially correct given deficiencies are based on standard engineering practice.

In 1988, the FHWA embarked on a long-term research, development, testing and critical review effort to produce an alternative, economic-based simulation procedure. The culmination of this effort was the development of the Highway Economic Requirements System (HERS). HERS was first utilized in the 1995 C&P report to develop one of the two highway investment requirement scenarios. In subsequent reports, HERS has been used to develop all of the highway scenarios.

Executive Order 12893, "Principles for Federal Infrastructure Investments," issued January 26, 1994, directs that Federal infrastructure investment be based on a systematic analysis of expected benefits and costs. This order provided additional momentum for the shift toward developing investment requirement analytical tools that would perform economic analysis.

In the 1997 C&P report, FTA introduced the Transit Economic Requirements Model (TERM), which was used to develop both of the transit investment requirement scenarios. TERM incorporates benefit cost analysis into its improvement selection procedures.

The FHWA is currently developing the National Bridge Investment Analysis System (BIAS), which will incorporate economic analysis into the bridge investment requirements in future C&P reports.