I-40 Widening Accelerated

The Triangle's Main Street is Interstate 40—connecting Hillsborough, Chapel Hill, Durham, Research Triangle Park, Morrisville, Cary, Raleigh, Garner, and Benson. In addition, I-40 interchanges with NC 147 (part of the Research Triangle Freeway corridor), I-540, I-440, US 1, US 15-501, and many other roadways that bring the Triangle together. Interstate 40 is the most heavily-traveled—and congested—highway in the region, and the only two-digit Interstate serving Wake County, the capital county and largest in the eastern half of North Carolina.

The Regional Transportation Alliance has identified the widening of I-40 (map) between Cary and Raleigh as our highest priority freeway expansion project in the Triangle. The roadway is only two lanes in each direction between the Wade Avenue split (exit 293) and I-440/US 1/US 64 (exit 297). NCDOT has completed several excellent freeway projects in the past two years, including the creation of the Knightdale bypass (US 64/264) and the reconstruction of US 1/64 in Cary. However, this section of I-40 remains a missing link from the new or expanded freeways to the south and east. In addition, I-40 between Raleigh and Cary is a critical bottleneck between Downtown Raleigh and the RDU/Research Triangle Park area.

Current traffic volumes exceed 140,000 per day near Research Triangle Park and 130,000 per day near RDU airport. Between Cary and Raleigh, traffic volumes are approximately 100,000 vehicles per day—far above the capacity of the freeway in this area, and leading to an evening rush hour that can last for three hours eastbound. NCDOT and the Federal Highway Administration have identified this section of I-40 between Raleigh and Cary, along with the I-40/I-540 interchange at the Durham/Wake line, as two of the three largest bottlenecks in the Triangle.

NCDOT estimates that a freeway reconstruction from four to eight lanes—effectively doubling the capacity—would cost more than $60 million. In addition, NCDOT estimates that a 50% capacity increase—from four to six lanes—can be accomplished for this section of I-40 for around $38 million, including widening bridges to allow for eight lanes in the future. In 2007, the Alliance focused on a 6-lane footprint for this section of I-40 as an intermediate, less expensive solution that would still provide a substantial degree of relief to area travelers on the Triangle's main street. NC DOT has incorporated the 6-lane solution in the 2008-2015 draft TIP (TIP changes)!

See the following pdf for current traffic volumes and morning and evening rush hour speeds along I-40. Click here for an interactive map of Alliance transportation priorities in the region.