I81 update

Engineers Explain "300-foot Fencing from the Ramp" Rule


Many property owners along Interstate 81 are discussing how interchanges will need to be expanded and changed when the heavily traveled highway is widened. The following is an explanation of a design rule promoted by the Federal Highway Administration for efficient and safe movement of traffic through interchanges.

Interstate roads designed and built for 1960s-era traffic are quickly wearing out their effectiveness to handle the changing traffic needs of the late 20th and early 21st centuries. This is very evident on Interstate 81, which has been the subject of recently completed studies.

As I-81 is redesigned, elements found in 1960s design standards have been updated. Among these design elements is what is commonly referred to as the "300-foot fencing from the ramps" rule.

This FHWA regulation is derived from guidelines established by the American Association of State Highway and Transportation Officials. The AASHTO guidelines are the agreed-upon road design standards established by road engineers for all 50 states. These standards bring consistency to safe road design and interstate travel patterns throughout the United States.

The 300-foot rule means that no entrances from private property should be allowed within 300 feet of an interchange ramp. Usually, fencing at the end of the ramp will define this area. The purpose of the 300-foot fencing from the ramps rule is to ensure safe access to these properties without endangering motorists traveling through the access area.

Future traffic volumes are expected to double in many interchange areas, necessitating critical safety design features that must be incorporated in every interchange configuration. Additionally, traffic patterns for many interchanges will change as local development increases.

As sections of I-81 are redesigned, VDOT will hold public meetings, and people will have the opportunity to comment on proposed designs. After considering public comments collected from the public meetings, VDOT Chief Engineer James Browder will determine if exceptions to the design standards, such as the 300-foot fencing from the ramps rule, are warranted and will seek agreement from FHWA. Exceptions to design standards require specific justification that VDOT’s chief engineer can support and are done on a project specific basis.

Admittedly, the issue is not an easy one to resolve with many business owners, but as the design phase is begun, safe and functional access for all properties will be a priority.

 Transportation Board Funds Next Steps Toward Widening

In December 1998, Virginia Department of Transportation Chief Engineer James Browder presented recommendations for Interstate 81 design priorities to the Commonwealth Transportation Board. These recommendations were developed by VDOT staff, members of the Federal Highway Administration and the consultants who performed the I-81 Improvement Studies, which were completed in fall 1998.

In spring 1999, the Commonwealth Transportation Board reviewed the recommended design priorities and included funding in its annual budget for the top priorities for the three transportation districts along the I-81 corridor.

(The Commonwealth Transportation Board makes funding decisions and approves construction plans for roads in Virginia. Members, representing each of the nine transportation districts as well as urban and rural interests, are appointed by the governor and approved by the General Assembly. The 17-member board guides VDOT much like a board of directors.)

In June, the Commonwealth Transportation Board adopted a $2.6 billion budget for VDOT for the fiscal year beginning July 1, 1999. The adopted spending plan is outlined in VDOT's Six-Year Construction Plan and includes funds for preliminary engineering for sections of I-81. Preliminary engineering involves developing detailed construction plans, surveying, evaluating environmental considerations and holding public meetings to present plans to the public.

For the Bristol transportation district, the board identified $2.5 million to perform a location study to consider possible alternatives for improving the I-81 and I-77 overlap in Wythe County. As part of the study, which is scheduled to begin in early 2000, engineers will perform an in-depth review of the environmental, cultural, historical, economic and traffic impacts of maintaining the current interstate overlap or separating the interstates. The study also will include information on a "no build" alternative. The board will review the information developed during this study when making a decision on future design plans for widening I-81 in this area.

For the Salem transportation district, the budget includes a total of $21 million to be allocated over the next three fiscal years toward the widening of I-81 in the Roanoke Valley. The funds will be used to draw up construction plans for a 16-mile section of I-81 that begins just south of Wildwood Road in Roanoke County and extends to two miles north of Exit 150 in Botetourt County. New interchange designs also will be included in this preliminary engineering.

Also in the Salem transportation district, the board identified two projects in Montgomery County to prepare for the future I-81 widening and to improve safety. The budget includes a total of $300,000 toward the preliminary engineering for extending acceleration and deceleration lanes at Exit 109 (Route 177) at Radford and making improvements at Exit 114 (Route 8) at Christiansburg. The budget also identifies $3 million for construction on these two interchanges.

In the Staunton transportation district, $2 million was budgeted over the next two fiscal years to design construction plans for an eight-mile section of I-81 in Frederick County. This section of I-81 extends through the Winchester area between mile markers 312 and 320.

Also in the Staunton district, $2 million was budgeted over the next two fiscal years to design construction plans for a 12.4-mile section of I-81 in Rockingham County. This section of I-81 extends through the Harrisonburg area between mile markers 240.6 and 253.

As part of the design process, public meetings will be held in the next several years on each of these projects. Depending on the availability of funding, construction could begin within the next six to ten years.

Return to top

Page last modified: April 7, 2014