US 401 field visit — an innovation that saves time and lives
Earlier this month, RTA held a field visit of US 401 North.
As we mentioned in a prior RTA blog, the US 401 corridor is a major connector for Franklin and Wake counties, and NCDOT has worked to improve the roadway over the past several years.
On October 19, several RTA members and partners had an opportunity to visit the US 401 / Mitchell Mill Road intersection, which is located slightly south of the newly relocated US 401 / Ligon Mill Road intersection. The intersection with Mitchell Mill has been simplified to a “continuous flow intersection” (CFI) configuration, with only two signal phases, that helps traffic flow and operates much better, and safer, than before.
US 401 southbound traffic headed for eastbound Mitchell Mill first enters an advance left turn lane bay that stops at a traffic signal, next to northbound traffic, at a location well before the main intersection. Once northbound traffic stops, the southbound left turning traffic then proceeds parallel to, but slightly east of, northbound traffic. This allows these displaced left turns to travel at the same time as through traffic at the main Mitchell Mill intersection, which is a significant time savings. In fact, the entire large signal now operates with only two vehicular signal phases, which improves capacity and delay.
As noted in our prior blog, this is the first CFI for NCDOT in the eastern half of North Carolina, and it hopefully will not be the last. NCDOT reports that this project saved about $15 million (50%) in cost versus an interchange at this location; the simplified signal phasing has also dramatically reduced both travel time and queue lengths during rush hour. Prior information from NCDOT shows that a CFI has 70% more capacity than a typical traffic signal. [Updated November 2, 2026: NCDOT pre-build analysis of this intersection reflected expected savings of more than 40% in both travel time and delay by using a CFI versus the existing traditional intersection.]
The regional business community applauds NCDOT for this timely improvement that is already helping with travel flows, commuting, commerce, and more. Plus, it opened around a year early, which has meant relief came earlier to travelers.
See below for a few photos of the field visit.
Let’s get moving,
Joe
Joe Milazzo II, PE
RTA Executive Director
RTA is the voice of the regional business community on transportation
[note: this post was updated November 2, 2026 to provide updated travel time and delay analysis information]
