I-40 through Research Triangle Park (RTP) between NC 147 (Future I-885) and I-540 is the busiest stretch of road within the state of North Carolina. According to the NCDOT, nearly 200,000 vehicles per day utilize I-40 just west of the I-540 interchange. There are also five busy interchanges within a three mile stretch leading to dangerous weaving, merge, and diverge movements. The implementation of local lanes on this stretch of I-40 would greatly enhance safety and ease of navigation through the busiest area of the Triangle.
The interchanges in question and gore to gore distances are as followed:
Exit 279 / NC 147 / Durham Freeway
.46 miles
Exit 280 / Davis Dr / RTP
.45 miles
Exit 281 / Miami Blvd
.25 miles
Exit 282 / Page Rd
.37 miles
Exit 283 / I-540
My proposed solution involves a local lane / collector-distributor (CD) lane hybrid system similar to the one on I-95 in Arlington, VA.
Vehicles traveling Eastbound on I-40 would split just West of Exit 279. Vehicles wishing to use Exits 279, 280, 281, and 282 would use the right lanes to enter the local lanes and proceed to their exits per usual. The left lanes would enjoy uninterrupted flow with the exception of the NC 147 SB On Ramp.
Vehicles traveling Westbound on I-40 would split just West of Exit 283. Vehicles wishing to use Exits 283, 282, 281, 280, and 279-A would use the right lanes to enter the local lanes and proceed to their exits per usual. The left lanes would enjoy uninterrupted flow with the exception of the NC 147 NB Off Ramp.
To ensure smooth tie-ins, an auxiliary lane would be added on I-40 from NC 147 to NC 54 (Exit 273) and on I-540 to Lumley Rd (Exit 3).
The conceptual sketches follow.
Conceptual Sketches – click to enlarge
The implementation of local lanes on this stretch of I-40 would greatly enhance safety and ease of navigation through the busiest area of the Triangle.
Phil Veasley 