North Carolina Highway System

Interstate 540 and North Carolina Highway 540 share a partially completed Interstate-grade beltway, also known as the Raleigh Outer Loop, around the city of Raleigh, in the U.S. state of North Carolina,

When completed, the beltway will total 70 miles (110 km) in length, surrounding the city of Raleigh and the towns of Apex, Cary, Garner, and Morrisville. The designation from I-540 and NC 540 happens at I-40, in Durham County, where I-540 goes east and NC 540 goes west.

The beltway is further broken down into four segments:

I-540 is the designation for the northern part of the perimeter loop around Raleigh (not to be confused with the I-440 Beltline). Known formally as the Northern Wake Freeway, it runs 26 miles (42 km) from I-40, in Durham County, to US 64/US 264, near Knightdale. Majority of the route is 6-lanes, with some major intersections at 8-lanes; the speed limit throughout is 65 mph (105 km/h).

NC 540 is the designation given to the Western Wake Freeway and future Southern and Eastern Wake Freeways. As of January 2013, the North Carolina state route traverses east–west from I-40, in Durham County to NC 55, in Holly Springs. Initially intended to be signed as an extension of the I-540 loop, the first section of the route bears mile markers and exit numbers for the complete Interstate loop, going from 66 to 69. In Mid-2012, this section of the beltway became part of the Triangle Expressway.

From NC 54 in Morrisville to NC 55 in Holly Springs, NC 540 is part of the Triangle Expressway. Tolls are collected all-electronically and camera enforced. Tolls are $0.15 per mile with NC Quick Pass or $0.24 per mile for non-NC Quick Pass drivers.

Toll rates are effective January 2, 2013:

Planning for the highway originally started in the early 1970s; by 1976, the "Northern Wake Expressway" was added to the planning map. In the mid-1980s, realizing that the growth in western Wake County may require more roads than planned, highway planners decided to expand the project as a new beltway around Raleigh. In 1992, construction began on the first 3-mile (4.8 km) section of the Northern Wake Expressway, connecting I-40 with US 70. On January 21, 1997, the freeway opened as Interstate 540.

In the following ten years, the now known Northern Wake Freeway (so not to be confused with the Triangle Expressway) made several extensions:

From 1999 to 2002, each additional section of the freeway was designated as Future 540, until it connected with US 1.

On July 14, 2007, a section of the loop from I-40 west to NC 54 and NC 55 was opened. However, the route is signed not as I-540 but as NC 540. Officials decided to change the designation in early July at the urging of the North Carolina Turnpike Authority (NCTA). Work on the western and southern portions of the beltway, if paid for by state funds, would possibly not open until 2030. At the request of several Wake County mayors, the NCTA in 2006 began studying the use of tolls to complete these portions of the Outer Loop.

The Authority concluded in early 2007 that it would be financially feasible to build the western section (along with an extended Durham Freeway, which combined would be called the "Triangle Expressway") using toll funds. The NCTA apparently never wanted an interstate designation for the Western Wake Parkway. To lessen motorist confusion about where I-540 ended, the route was truncated to the I-40 interchange. All I-540 signs that were put up along the unopened stretch between I-40 and NC 55 were taken down in early July 2007; the new section is now signed as NC 540. (In addition, I-540 as a completed loop would violate the Interstate numbering convention regarding three-digit routes, as spurs begin with an odd number and loops with an even number, and at one point, I-640 â€” the last remaining available number within the state, as I-240, I-440 and I-840 are already taken â€” was proposed for the loop.)

Work to build the Western Wake Freeway, which would be renamed the "Western Wake Parkway" under the toll proposal, began August 12, 2009, with the Triangle Parkway portion opening in December 2011, and Western Wake portion scheduled to open in two phases in 2012.

In October 2008, the authority was unable to issue bonds to fund the Western Wake Turnpike project as planned due to market conditions affecting municipal bonds such as those. On July 29, 2009, the Authority closed on a revised $1.01 billion bond plan, consisting of $270 million in toll revenue bonds, $353 million in Build America Bonds, and a $387 million loan from the U.S. Department of Transportation under the Transportation Infrastructure Finance and Innovation Act.

Groundbreaking was held on August 12, 2009 at the west end of Interstate 540. "A dozen dignitaries" used shovels painted gold as 150 watched.

After work began on Western Wake Parkway in 2009, engineering and environmental studies began a year later for the Southern and Eastern Wake Freeways, also known as the Triangle Expressway Southeast Extension. Construction would begin on 2014 and be completed by 2019; however, it was delayed on March 2011 by the enactment of North Carolina Session Law 2011-7 (N.C. S.L. 2011-7), which forbid NCDOT to consider a few alternative routes.

In 2010, NCDOT made an interchange improvement at I-540/I-40; adding an additional auxiliary lane from I-540 south to I-40 west, at a cost of $4.8 million.

The completed Triangle Parkway, the first section of the Triangle Expressway, with its connection to NC 540, opened on December 8, 2011, reestablishing exit 67. Collection of tolls began on January 3, 2012. On August 1, 2012, the first phase of the Western Wake Freeway opened, connecting NC 55 in Morrisville (exit 66) to US 64 in Apex. The next day tolling began on the previously open section from NC 54 to NC 55. The final phase of the tolled section of NC 540, from US 64 to NC 55 north of Holly Springs opened on December 20, 2012. Tolling for this section began January 2, 2013. On January 3, 2013, the Triangle Expressway began to accept E-Z Pass transponders as payment for the toll road. NC Quick Pass transponders also work on the tolls in the northeast.

The Southern Wake Expressway would connect Holly Springs with Garner. The route for the southern leg known as the Orange Route, on maps since the 1990s, would affect only a few people, but it would potentially hurt the endangered dwarf wedge mussel, so the U.S. Fish and Wildlife Service asked for other routes to be considered. In September 2010, a new map showed several other routes, including the controversial Red Route, which many Garner-area residents protested in a December 2010 meeting; a total of 3,000 signatures on petitions opposed the route as well. A Pink Route would run along the Orange Route to Lake Benson and then join with the Red Route at I-40; residents opposed this plan as well. Another possibility would be to prevent pollution that would affect the mussels, mainly around bridges.