ENGINEERING ECONOMIC ANALYSIS TOOLS

Highway Economic

Requirements System

for State Use

T

he Highway Economic Requirements System–State Version (HERS-ST) is a

software package that predicts the investment required to achieve certain

highway system performance levels. Alternatively, the software can be

used to estimate the highway system performance that would result given

various investment levels. HERS-ST considers capital improvement projects

directed at correcting pavement and capacity deficiencies.

The HERS-ST model is a direct extension of the national-level HERS model. This

model was developed by the Federal Highway Administration (FHWA) to examine

the relationship between national investment levels and the condition and performance of the Nation’s highways. FHWA uses the model to estimate future investment required to either maintain or improve the Nation’s highway system. FHWA

provides this information to the U.S. Congress on a biennial basis.

The HERS concept has been extensively and favorably reviewed over the past

decade. Most recently the U.S. General Accounting Office evaluated the HERS

approach and found it reasonable and appropriate for application at both the

Federal and State levels.

Potential Uses

HERS-ST has many practical applications in a State transportation agency.

Following are some of the software’s potential uses:

• Long-range planning

• “What if” analysis

• Programming

• Complying with GASB Statement 34

• Performance measures

• Congestion management

• Needs assessment

• Data management

• Legislative decision support

Software Description

The HERS-ST software is an easy-to-use, Microsoft Windows based application.

Interview screens, or “wizards,” are used to facilitate the entry and editing of

input data. For example, importing the highway data is as straightforward as

clicking a couple of buttons, HERS-ST will even check the data and warn the

user of any possible data errors.

HERS-ST is also flexible. When it is time to run the HERS-ST analysis, the

user selects the type of scenario to be performed and clicks a button. There are a

number of different ways that the user can choose to view the analysis results.

HERS-ST uses engineering

standards to identify highway

deficiencies and applies

economic criteria to select the

most cost-effective mix of

highway system improvements.
Examples of Questions That HERS-ST Will Answer

• How will a reduction (or increase) of x percent in highway

investment levels affect the condition and performance of

the State’s highway system over the next 20 years?

• What level of future investment is required in a State’s

highway system to ensure that average effective travel

speeds on the system are maintained?

• What level of investment is required to make all economically beneficial improvements on the system (that is, those

projects where benefits exceed costs)?

• What are reasonable performance targets given funding,

policy, and customer satisfaction objectives?

To request copies of HERS-ST documents or to inquire

about the program, please contact:

David R. Winter, P.E.

FHWA Office of Asset Management

HIAM-30, Room 3211

400 Seventh Street, SW

Washington, DC 20590

Tel: 202-366-4631

E-mail: david.winter@fhwa.dot.gov

Web site:www.fhwa.dot.gov/infrastructure/asstmgmt

Various summary reports allow the user to quickly

determine how the system as a whole responds, while

the section-specific output allows the user to view the

impacts on each individual highway section.

Users of all skill levels can create a wide variety of

maps, charts, tables, and reports. With HERS-ST’s

built-in graphical information system, the user can

spatially view the HERS-ST input and analysis

output. There are built-in charts and reports for the

novice user, “wizards” and queries for the intermediate user, and the ability to create ad hoc charts and

reports for the experienced user.

How the HERS-ST Model Works

The HERS-ST software simulates the selection and

implementation of highway capital improvements

consistent with the principles of incremental benefitcost analysis. The analysis considers travel time, safety,

vehicle operating, emissions, and highway agency costs.

The model optimizes highway investment given funding

constraints or performance objectives specified by the

analyst.

As input, HERS-ST accepts highway-section records in

the Highway Performance Monitoring System format. For

each highway section, the model predicts future condition

and capacity deficiencies based on section-specific information. The model identifies a set of alternative improvements to correct each deficiency and determines a benefitcost ratio for each potential improvement. The most

economically attractive improvement for each facility is

identified. Projects to be implemented are determined by

comparing the relative merit (e.g., benefit-cost ratios) of

each candidate improvement.

When funding is available, HERS-ST simulates

implementation of all projects with benefits in excess of

costs. Given funding constraints or user-specified

performance objectives, HERS-ST selects those projects

with the highest benefit/cost ratios until the public

agency funds are exhausted, therefore maximizing the

combined highway user and highway agency benefits.

The Future of HERS-ST

FHWA is committed to the long-term support and

enhancement of HERS-ST. To accommodate users and

solicit their feedback, a user’s group has been established. Users are encouraged to register through the

HERS-ST Web site listed below. Registered users will

be notified via e-mail of future events and software

revisions. The Web site also contains a community

of practice, where users can post HERS-ST related

comments and questions. Updated versions of the

software are routinely posted at this Web site; CDs

containing the software and documents are also

available upon request.

August 2003

Publication No. FHWA-IF-02-003