Proposed Concepts

Overarching Concepts

Several overarching concepts have been identified and will be evaluated for possible implementation along I-35 within the three-county area. In some cases, these concepts work best if implemented for longer stretches of I-35 while others can be effectively targeted at specific locations such as intersections. Everything shown here is conceptual in nature and subject to change. No changes will be made to I-35 until the concepts are fully vetted technically and publicly.

Future Transportation Corridor (FTC)

One of the concepts being explored is the idea of adding one lane in each direction of I-35. This “future transportation corridor” or FTC would be a “place holder” of sufficient width to accommodate the possible future construction of the additional lanes. To date, no assumptions have been made as to the type or design of the future lanes. The FTC could accommodate additional general purpose lanes, express lanes, high occupancy lanes, or other types of special use lanes. An FTC will be evaluated from the connection to SH 130 in the north to the connection with Centerpoint Road in the south.

Super Streets

A “super street” is a roadway with intersections in which the cross-street traffic is prohibited from going straight through or turning left. Instead, traffic desiring to go through the intersection or turn left, must first turn right (in purple in the image to the right). After making the right turn, the driver can access a U-turn (in green in the image below) to proceed in the desired direction. The super street concept reduces the number of traffic signal phases required to move traffic through the intersection. This, in turn, allows for longer green times on the major roadway; thus, reducing congestion caused by the signals. Bicyclists and pedestrians will still be able to cross I-35 on the overpass (in orange in the image below).

• View the fact sheet for more information on super streets.

Collector-Distributor Roads

Located between the I-35 mainlanes and the existing frontage roads, collector-distributor roads (in blue in the image to the right) would allow through traffic (that traffic not needing to turn onto the intersecting street) to by-pass signalized intersections. Collector-distributors also allow the merging from entrances and exits to happen on the collector-distributor road rather than on the I-35 mainlanes which serves to improve flow on the mainlanes. Possible construction of collector-distributors will be evalauted at intersections throughout the corridor.

• View the fact sheet for more information on collector-distributor roads

Innovative Intersection Solutions

Alternative ways to accommodate left-turning movements and improve traffic flow through intersections will be evaluated. These intersections reduce or remove the need for signals at intersections, resulting in greater green time and reduced congestion on the roadway network. Some innovative intersection options being explored along I-35 include diverging diamonds, roundabouts, and others.

• View the fact sheet for more information on innovative intersection solutions.
• View a Diverging Diamond Interchange Visualization by the North Carolina Department of Transportations

Bike/Pedestrian

The need for improved bicycle and pedestrian treatments is being explored along the entire corridor. The goal is to provide or enhance connections to existing and planned bicycle lanes/routes and key sidewalk linkages along and across the corridor.

• View improvement concepts

Traffic Incident Management

Crashes on I-35 are a major source of severe congestion. Some of the possible improvements involve working with police, fire, and EMS to provide better incident management. Possibilities include smarter tools and better contracting procedures for faster incident clearance, and improved driver information (apps, dynamic messages, and travel times).

Transit

The Future Transportation Corridor mentioned above could be used to provide transit improvements such as express bus service. This would allow Capital Metro to provide better access to planned and operational park and ride lots and better service for commuters.

• View fact sheet for more information on express bus service.

Ramp Modifications

In some instances, it may be possible to modify ramps in a way that would “smooth” traffic flow and help vehicles on I-35 move more efficiently. Ramp relocations and ramp reversals may reduce stop-and-go traffic at critical locations. Ramps can be “metered” to manage the flow of traffic. These and other ramp improvement strategies will be explored to improve safety and mobility within the I-35 corridor.

• More information on ramp configurations and ramp flow control.

Turn-Around Bridges and Other Improvements

Turn-around bridges will be considered at several locations to reduce congestion and improve mobility at intersections. These bridges allow U-turns to be made easily and without the need to travel through signalized intersections. Auxiliary lanes (added lanes between entrances and exits) also serve to improve mobility and safety. These strategies along with better signalization and dedicated right-turn lanes will be explored to improve mobility corridor-wide.