MARTINSBURG -- A report prepared for traffic planners in the Eastern Panhandle outlines the need to add travel lanes to Interstate 81 in both the northern end of Berkeley County to the Maryland line and in the southern end of the county to the Virginia line.

The portion of I-81 in the center of the county around Martinsburg has already been upgraded to six lanes.

The transportation report, prepared by Cambridge Systematics Inc. of Chevy Chase, Md., does cite a major hitch in such an expansion -- no funding exists for such improvements.

"Perhaps the most critical unmeet needs are those associated with the Interstate highway system in the region," the report notes.

The northern I-81 expansion has a price tag of more than $66 million while enlarging the road from Martinsburg to the Virginia line would cost more than $190 million, according to the report.

With the Eastern Panhandle's population predicted to grow another 66 percent in the coming quarter century, the current, largely four-lane interstate running through Berkeley County would likely devolve into stop-and-go traffic, explained Lewis M. Grimm, who prepared the report for Cambridge.

But even with I-81 a virtual parking lot, the Panhandle likely would still draw new residents from even more crowded regions in Northern Virginia and suburban Maryland where housing costs are considerably steeper, said Robert Gordon, the executive director for the Region 9 Eastern Panhandle Regional Planning and Development Council.

While the Panhandle's population growth might not be hurt by such congestion, stop-and-go traffic on I-81 would almost certainly hurt the area's business prospects, Grimm's report states.

The ability to travel easily through Berkeley County is essential to the "safe and efficient functioning of the Interstate highway system" to Maryland, Pennsylvania, Virginia, West Virginia and the broader mid-Atlantic region, Grimm notes in the report.

"Failure to address these issues in a timely fashion has the potential to severely constrain the long-term economic viability of the region and jurisdictions in neighboring states," the report states.

Tractor-trailer traffic is a major contributor to the current congestion on I-81, Grimm said in a phone interview. The Interstate highway system begun during the Eisenhower administration didn't anticipate today's heavy use of big trucks in then-rural areas such as Berkeley County.

It was thanks largely to these new highways that the Panhandle began to be seen as a bedroom community for those with jobs in and around Washington. When I-81 opened in the late 1960s, the population of Berkeley County stood at just over 36,000. In the latest U.S. Census estimate from 2003, the county had a population of 85,272.

In the 1960s, Grimm said, tractor-trailers were predicted to make up about a third of the traffic on rural interstates. Today, he said, more than half of the vehicles using I-81 in Berkeley County are big rigs, and the number is predicted to continue to grow.

"Tractor trailers take up a lot more room on the highway than individual cars so that adds to congestion," Grimm said. "They also weigh a lot more so they add more to the wear and tear we see on the highways."

The new traffic report is a planning document required by federal highway officials, which since 1990 have viewed this region -- Washington County in Maryland and Berkeley and Jefferson in West Virginia -- as a single metropolitan area.

The three counties -- required to work together as the Hagerstown-Eastern Panhandle Metropolitan Planning Organization -- had not completed a comprehensive transportation report since the mid-1990s.

Another project outlined in the report carries a price tag of between $141.4 million to $783.3 million to create a four-lane U.S. 340 in the Harpers Ferry area, where the Potomac and Shenandoah rivers converge. The most expensive option involves a realigned route with a tunnel.

Two additional West Virginia projects categorized as "unfunded needs" in Grimm's MPO report are:

• $149 million to widen U.S. 522 between Washington County, Md., and the West Virginia line.
• $80.5 million to create a four-lane bypass from W.Va. 9 in Berkeley County to Shepherdstown in Jefferson County.

The report will now go to Maryland transportation officials as well as the West Virginia Department of Transportation in Charleston.