What are “innovative intersections”?
Innovative intersections use non-traditional methods to move traffic through a junction of crossroads. They remove conflict points to improve safety and have added benefits including improved efficiency, higher resiliency and lower maintenance costs. Innovative intersections are becoming more prevalent in the United States and within Texas in particular.
The most common types of innovative intersections are:
- Modern roundabout
- Continuous green-T (CGT)
- Grade separated intersection
- Median U-turn (MUT)
- Restricted crossing U-turn (RCUT)
- Displaced left-turn (DLT)
- Contraflow left
- Continuous flow interchange (CFI)
- Diverging diamond
- Single-point urban interchange (SPUI)
- Partial cloverleaf
Benefits of innovative intersections
Due to the reduction of conflict points, innovative intersections statistically reduce the number of serious injury and fatal crashes. In roundabouts in particular, fatal crashes are reduced by over 90%. These intersections are a critical tool for saving lives on the Road to Zero. The many benefits of roundabouts include:
- Lower vehicle speed and both fewer and less severe conflict points, causing an overwhelming reduction in fatal and injury crashes.
- Yield-on-entry best utilizes intersection space.
- Reduced fuel consumption causes less emissions.
- Pairs well with access management projects (particularly for large trucks).
- Reduced costs over time compared to a signal.
- Continues to function in a power outage.
Common roundabout concerns
The table below lists the most common concerns in regards to roundabout implementation. As you can see, while there are some likely “dealbreakers”, there are surprisingly few of them, and most of the common concerns are really not a problem, if careful attention is paid to design and proper outreach. Please note that this table addresses common concerns at a very high-level, and careful consideration of all aspects of an intersection is required during planning and design.
TxDOT has started a new program devoted to innovative intersections. The goal of this program is to:
Develop and deploy resources to support implementation.
Provide training on planning, design, construction and maintenance.
Convey the benefits of innovative intersections.
Maintain statistical information on implementation across the state.
- Learn more about roundabouts from Insurance Institute for Highway Safety (IIHS) & Highway Loss Data Institute (HLDI)
- TxDOT Roadway Design Manual, Appendix E
- Proven Safety Countermeasures | FHWA (dot.gov)
- Roundabouts | FHWA (dot.gov)
- NCHRP Report 1043 – the latest and greatest Guide for Roundabout planning and design.
- Reduced Left-Turn Conflict Intersections | FHWA (dot.gov)