Crossover Intersections
Some intersection designs direct some or all traffic to cross over to the left–hand side of the roadway to facilitate unopposed left–turn movements. These designs can improve safety and reduce congestion at the intersection.
The two most common crossover–based designs are the diverging diamond interchange (DDI) and the displaced left–turn (DLT) Intersection.
Outreach and Education Resources
- Alternative Intersection Video Playlist – includes DDI and
DLT intersections
Diverging Diamond Interchanges
- Diverging Diamond Interchange Brochure
- Diverging Diamond Interchange Case Studies
Displaced Left–Turn Intersections
- Displaced Left–Turn Intersection Brochure
- Displaced Left–Turn Case Studies
Technical Materials and Research
Diverging Diamond Interchanges
- Diverging Diamond Interchange Informational Guide, Second Edition
- Performance of Alternative Diamond Interchange Forms
- Exploring Corridor Operations in the Vicinity of a Diverging Diamond Interchange (DDI): Final Report
- Comprehensive Safety Assessment Methodology for Innovative Geometric Designs
Displaced Left–Turn Intersections
- Displaced Left–Turn Intersection Informational Guide
- Use of Innovative Intersection Designs for Improving Mobility and Reducing Roadway Traffic Congestion
Connections to Other Transportation Safety Topics
- The Federal Highway Administration's (FHWA) EDC–2 initiative for Intersection and Interchange Geometrics developed educational materials about DDIs, DLTs, and other intersection designs
- Roundabout, restricted crossing U–turn (RCUT) , and median U–turn (MUT) intersection designs also offer improved safety due to fewer conflict points
- Intersection Control Evaluation (ICE) policies and tools can help agencies choose an optimal intersection design
- Low–cost strategies and countermeasures can improve safety. Learn more at Stop–Controlled Intersection Safety and Signalized Intersection Safety
Last updated: Monday, August 23, 2021