Publication Number: FHWA-SA-98-023
Date: June 1998

FHWA Works with States and Provinces to Fix Gaps in LTPP Data

Since its beginning more than a decade ago, the long-term pavement performance (LTPP) program has collected enough data to fill more than 40,000 floppy disks. While most of the data are complete and accurate, analyses indicate that some gaps exist and some of the data do not meet quality control standards. So this summer, the Federal Highway Administration (FHWA) is holding meetings with highway agencies in States and Provinces to develop plans for addressing those gaps and questions about quality.

"Resolving issues related to missing and questionable data is vital to the success of the LTPP program and requires the active support and participation of the States and Provinces," says Charlie Churilla, chief of FHWA's Pavement Performance Division, which oversees the LTPP program.

The effort began last year when FHWA reorganized the LTPP program's data processing procedures and upgraded computer systems to ensure that data are processed quickly and that any missing or questionable data are rapidly identified. FHWA then reviewed all the data collected so far from the more than 2,400 asphalt and portland cement concrete pavement test sections in the United States and Canada. For each site, FHWA staff looked for missing data, such as incomplete data on traffic or the materials used at a test site, and so-called questionable data, which had failed quality control checks or was not collected in compliance with LTPP procedures. The results of these reviews were compiled into data status reports that identify the gaps and questions regarding data from each State and Province.

In April, FHWA staff presented their findings to the American Association of State Highway and Transportation Officials' (AASHTO) Standing Committee on Highways (SCOH). In response, SCOH issued a resolution calling on FHWA and the States to address the missing and questionable data in order to ensure that the LTPP program meets its goals (see sidebar).

With AASHTO's support, FHWA has begun the next stage of its data resolution effort. Since May, staff from FHWA's Pavement Performance Division, the FHWA division offices, and the LTPP regional coordination offices have been meeting with the States and Provinces to review each one's data status report, discuss the completeness and quality of the data, and develop a data resolution action plan. The meetings will continue through July.

The data resolution plans will emphasize practical solutions, says FHWA's Monte Symons. If several types of data are missing from an experiment site and there is no easy way to collect the data, for example, the data resolution plan may recommend abandoning data collection at the site and focusing time and money on more valuable sites instead.

"The goal is to get a complete suite of data across all areas for the sites that will still be monitored," says Symons. "If we know we're not going to get that data from a site, FHWA and the States and Provinces can reallocate resources to sites where we can."

The meetings with States will also give FHWA a chance to identify any changes that should be made to how it operates the LTPP program. For example, says Symons, it may be necessary to change some procedures for collecting data.

The process is going well so far, says Symons. "Our pilot meetings in April with Mississippi, Montana, Virginia, and Michigan were very well received."

Al Crawley, research engineer with the Mississippi Department of Transportation (DOT), agrees with Symons' assessment. "We thought the meeting went very amicably," he says. "We reviewed where Mississippi was and what needed to be addressed, then prioritized the missing data so Mississippi DOT could address the areas that will have the most importance to the LTPP program."

After the highway agencies have met with the LTPP and FHWA staff, they will have several months to collect missing data. The Pavement Performance Division will complete its data resolution effort by fall 1998.

For more information, contact Monte Symons at FHWA (phone: 703-285-2730; fax: 703-285-2767; email: monte.symons@fhwa.dot.gov).

AASHTO STANDING COMMITTEE ON HIGHWAYS RESOLUTION

In April, the AASHTO Standing Committee on Highways (SCOH) passed a resolution entitled, "Addressing the Data Deficiencies in the Long-Term Pavement Performance (LTPP) Studies." The resolution reads, in part:

Whereas, the attainment of the goals of LTPP is dependent on the quality and completeness of the data obtained; and

Whereas, technical considerations based on data quality and completeness suggest that monitoring should be discontinued on those pavement sections where major data deficiencies exist and cannot be overcome; and

Whereas, data deficiencies on some pavement sections can only be overcome with the renewed and continued cooperation of the member agencies;

Now, therefore, be it resolved that SCOH encourages the FHWA, as steward of the LTPP database to inform each member agency by August 1998 of the status of the data set, identifying apparent deficiencies for each of its pavement sections, and emphasizing the benefits of continued monitoring of some sections and discontinuation of monitoring of other sections; and

Be it resolved that the AASHTO member agencies...act to eliminate the data deficiencies on their pavement sections by October, 1998....

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