Fulfilling the LTPP Promise
Thirteen years ago, the Long-Term Pavement Performance (LTPP) initiative
was launched with the goal of achieving longer-lasting, better performing
pavements. Fulfilling the Promise of Better Roads, a new report by
the Transportation Research Board's (TRB) LTPP Committee, examines
what the program has accomplished so far and what remains to be done.
The report also examines the level of funding needed to successfully
conduct the LTPP program from 2004 to 2009.
The LTPP program's three main activities are data collection, data
analysis, and product development. Data collected from eight General
Pavement Studies (GPS) and nine Specific Pavement Studies (SPS) experiments
are stored in the LTPP database. This 13-gigabyte database is the
most comprehensive source of pavement performance data ever assembled.
The combined studies currently encompass about 2,100 in-service test
sections, with such collection categories as climate, traffic volumes
and loads, materials properties, and pavement condition.
LTPP data analysis projects have resulted in the development of a
number of products for the highway community, including the LTPPBind
software, which allows engineers to more accurately select the correct
Superpave asphalt binder for their specific environmental conditions;
the 1998 Supplement to the American Association of State Highway and
Transportation Officials (AASHTO) Design Guide and the associated
Rigid Pavement Design Software; and the DataPave software, which offers
commonly requested data in an easy-to-use CD format.
The LTPP program now stands at a crossroads. The Transportation Equity
Act for the 21st Century (TEA-21) expires in September 2003, and the
next Reauthorizion period will be crucial to the accomplishment of
the LTPP program's goals. As the report notes, much has been accomplished,
but several potentially significant gaps must be closed before data
collection is completed. These gaps include: 1) traffic volume and
load data collection at the SPS sites, 2) selected materials testing
on certain SPS projects, and 3) completion of performance monitoring
data collection on a schedule that identifies the onset of distress
at each test section.
The report also recommends an assessment of the LTPP program be conducted
in 2006 to determine whether data collection may be concluded by 2009
or will have to continue beyond that date to capture performance data
from SPS test sections that were built in the late 1990s. This is
an important decision since, as the report states, "All data
components in the data collection plan appear there because they can
contribute to our understanding of the relationship among environment,
pavement 'loading,' and performance. Any portion of the performance
data that is missing is a gap in the database that could prevent complete
development of this understanding."
In the end, achieving the LTPP program's goals will also depend upon
funding. TEA-21 provided less money to the LTPP program than did its
legislative precursor, the Intermodal Surface Transportation Efficiency
Act. AASHTO and the National Cooperative Highway Research Program
addressed a portion of the shortfall by infusing about $4.4 million
per year into the program in 1999, 2000, and 2001, but this infusion
comes at the expense of not funding other research projects. "To
execute its plans for data collection, data analysis, and product
development," notes the report, "LTPP needs to receive sufficient
funding from 2004 to 2009."
The report's recommendations include giving the highest priority
to closing the data gaps and implementing the enhanced data collection
schedule between 2004 and 2009. The report also recommends that plans
be developed to "secure the legacy" of the LTPP program.
These plans should cover such activities as storing and maintaining
the LTPP database and Materials Reference Library and continuing implementation
of LTPP data analysis and product development beyond the conclusion
of the program.
For more information on the report or to obtain a copy, contact Cynthia
Baker at TRB, cbaker@nas.edu. For more information on the LTPP program,
contact Aramis Lopez at FHWA, 202-493-3145 (email: aramis.lopez@fhwa.dot.gov).
Information can also be found on the LTPP Web site at http://www.fhwa.dot.gov/pavement/ltpp/
or by sending an email to ltppinfo@fhwa.dot.gov.
| You
can learn more about the LTPP program's recent work by checking
out the new report, LTPP: Year in Review 2001 (Publication No.
FHWA-RD-02-049). The report outlines the program's accomplishments
last year and provides an overview of key initiatives for 2002.
The accomplishments for 2001 included supporting the development
of the National Cooperative Highway Research Program's 2002 Guide
for Design of New and Rehabilitated Pavement Structures and releasing
the updated DataPave 3.0 software, which provides easy access
to LTPP data. 2002 initiatives will include finalizing a study
of pavement edge drains at Specific Pavement Study (SPS) -1, -2,
and -6 sites and continuing a pooled fund study to improve traffic
data collection at the SPS -1, -2, -5, -6, and -8 projects. |
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Articles
in this issue:
Pavement Preservation Forum II: Investing in
the Future
A New and Improved High-Performance
Concrete
Welcome to the Word of Nondestructive Testing
Fulfilling the LTPP Promise
Highway Technology Calendar
FHWCA Announces New Source of Bridge Preservation
Funding
