Bobby Hopper Tunnel
Entering the tunnel northbound
|Other name(s)||Bunyard Tunnel (prior to designation)|
|Location||Unnamed mountain near Winslow, Arkansas, in south Washington County|
|Operator||Arkansas State Highway and Transportation Department|
|Design engineer||J. F. Shea Company|
|Length||1,595.2 ft (486.2 m)|
|No. of lanes||4, 2 per bore|
|Tunnel clearance||25 ft (7.6 m)|
|Width||38 ft (12 m)|
The tunnel's twin bores are each approximately 1,600 feet (0.49 km) in length, 38 feet (12 m) wide and 25 feet (7.6 m) tall (as measured from the roadway to the top of the tunnel arch). A prominent feature of the tunnel is the noticeably inclined gradient of each bore and its associated roadway. Southbound traffic experiences a significant descending gradient inside the tunnel, while northbound traffic experiences a corresponding ascending gradient. Cross-passages occur every 265 feet (81 m) allowing for five emergency ways in. Besides paved openings, the tunnel has traffic signals, lighting, message signs, carbon monoxide monitors, fire protection, and closed-circuit television systems to monitor traffic remotely at the Fort Smith highway department district headquarters.
The tunnel was named for the director of the Arkansas Highway Commission (a resident of nearby Springdale, Arkansas) during the time of its construction. This is the only highway tunnel in the state of Arkansas; there are seven railroad tunnels but only one highway tunnel in the state. The Bobby Hopper Tunnel is located on I-49 in Washington County just north of the Crawford County line with its closest exit at Winslow.
U.S. Route 71 (US 71) once classified as "one of the most dangerous highways in America," includes a perilous stretch between Alma and Fayetteville through the Ozark Plateau. Thus, construction of an alternate route was designed to make the trip safer, as well as reducing travel time. Approved in 1987 and completed in 1999, at a cost of $458 million, the alternate route, eventually named I-49, had an obstacle of an unnamed 1,800-foot-tall (550 m) peak just north of the Washington–Crawford county line in what John Haman of Arkansas Business called "smack in the middle of motoring wilderness." A tunnel feasibility study was awarded to Garver USA, which subcontracted with Sverdrup Corporation of Maryland Heights, Missouri, and TapanAm Associates, Inc., of Kansas City, Missouri, to determine the best option—a tunnel. The alternative would disfigure the topography and necessitate a 200-foot (61 m) cut creating 8 million cubic yards (6.1×106 m3) of debris to be disposed, as it was not usable within the project.
At an elevation of 1,640 feet (500 m) above sea level, twin parallel tunnels were mined, not bored, through the mountain in a horseshoe contour since a circular shape, like that used in sewer or train projects, was not needed. Blasting, drilling, and excavation removed native shale and sandstone rocks, slowly chipping to the desired width and length. The hollowed-out channel was lined with reinforced concrete, as were both openings. The finished total length is 1,595.2 feet (486.2 m), with a width of 38 feet (12 m) and a height of 25 feet (7.6 m), as measured from the roadway to the top of the arch, allowing for two lanes of traffic and shoulder space on each portal.
- Arkansas State Highway and Transportation Department. Washington County, Arkansas (PDF) (Map). State Highway Route and Section Maps. Little Rock: Arkansas State Highway and Transportation Department. Retrieved May 17, 2011.