Big Rock Interchange is the

I-430 Interstate 430 (I-430) is a Interstate highway in Pulaski County, Arkansas, that bypasses the cities of Little Rock and North Little Rock. I-430 begins at an interchange southwest of Downtown Little Rock with I-30, U.S. Highway 67 (U ...

/ I-630/Chenal Parkway interchange in west

Little Rock, Arkansas (The Little Rock, The "Little Rock") , government_type = council-manager government, Council-manager , leader_title = List of mayors of Little Rock, Arkansas, Mayor , leader_name = Frank Scott Jr. , leader_ ...

. The name is derived from a large rock formation discovered during expansion. The interchange was originally constructed in 1977, then in the mid-2000s it was decided to expand the interchange to alleviate congestion. In 2011 an outcropping of Pennsylvanian Jackfork Formation

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

and surrounding

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

was discovered in the southeast quadrant of the project. The formation was estimated to weigh about 5 million pounds. Due to the size and hardness of the sandstone it was decided to leave the unique and distinctive formation in place as a landmark, rather than use explosives or some other method to try to remove it, and it was dubbed "The Big Rock". When the original I-430 and I-630 interchange was constructed, about 14,000 vehicles a day traveled down each Interstate, and I-630 ended at Shakleford Road with a traffic signal. With expansion and growth in west Little Rock, and particularly in the

Chenal Valley Chenal Valley () is a sizable and more recently developed section of Little Rock, Arkansas, located in the west-central part of the city and serves as a major economic and residential hub in west Little Rock. Its name is derived from the area's Sh ...

neighborhood, the interchange had become progressively more congested by the early 2000s. In 2004 the

Arkansas Highway and Transportation Department The Arkansas Department of Transportation (ArDOT), formerly the Arkansas Highway and Transportation Department, is a government department in the U.S. state of Arkansas. Its mission is to provide a safe, efficient, aesthetically pleasing and en ...

began a study to expand the interchange. The first of three phases began January 2009. First phase was construction of an additional I-630 west to I-430 north lane, modification to Financial Centre Parkway (Chenal Parkway) just west of Shackleford Road, and an additional traffic signal added to Hermitage Drive. Phase two involved preparing the interchange for future work and mainly involved the I-430 bridge over I-630 which was lengthened. Phase three completed the flyover lanes. The $150 million makeover took over six years to complete. In the end it eased congestion for over 200,000 vehicles that use the interchange daily.

Sources

Arkansas Highways

Arkansas Online

AMP

Arkansas Geological
Transportation in Arkansas Interstate 30 Interstate Highways in Arkansas Transportation in Little Rock, Arkansas Transportation in Pulaski County, Arkansas Road interchanges in the United States {{Arkansas-road-stub