Medians

The presence or absence of a median has a substantial impact on roadway operations and safety.

Medians can be categorized into the following:

Non-traversable median: a physical barrier in the roadway that separates traffic traveling in opposite directions, such as a concrete barrier or a landscaped island. These are recommended for all new or reconstructed multi-lane highways. Additional details are included in the Kentucky Median Type Guidance below.
Continuous two-way left-turn lane (TWLTL): a continuous lane located between opposing traffic streams that provides a refuge area for vehicles to complete left turns from both directions. A TWLTL is only recommended in limited applications.

References

Kentucky Median Type Guidance
The purpose of this technical white paper is to provide a summary of the proposed median type standards for incorporation in the Kentucky Highway Access Management Plan. The proposed standards are based on independent engineering analysis and previous research conducted on median type applications. The results of these studies are presented below.

Median Type Guidelines.pdf

Florida Median Handbook
The purpose of this document is to guide the professional through the existing rules, standards and procedures, as well as to provide current national guidance on the best ways to plan for medians and median openings. Unless stated otherwise or specifically referenced, this is not a set of standards or a Departmental Procedure but is a comprehensive guide to allow the professional to make the best decisions on median planning.

Florida Median Handbook

Median Opening Locations
This study evaluated the impacts of the offset distance between driveway exits and downstream median opening or signalized intersection on the safety and operational performance of vehicles making right-turns followed by U-turns. This study evaluated the impacts of offset distance under 4 different roadway conditions including...

Median Opening Research.pdf

NCHRP 524 Safety of U-Turns at Unsignalized Median Openings
Many state and local transportation agencies are considering installing nontraversable medians on multilane arterial highways to improve safety and travel times. Business and property owners often resist such improvements because they and their customers may be denied the opportunity for direct left-turn access to or from their property.

NCHRP 524 U-turn Safety.pdf

Michigan Left-Turn
Michigan-Left-Turn

3/4 Intersection Design and Photo
View the design of the intersection as well as a photograph of the implementation of that design.

Three Quarters Intersection Design and Photo.pdf

Median Intersection Design for Rural High-Speed Divided Highways
The purpose of this study was to explore common safety issues, discuss alternative safety improvements at rural intersections and to report experiential data collected from agencies who have tried alternative methods. The report contains 10 case studies showing how different alternatives have been used in the field.
Median Intersection Design for Rural High-Speed Divided Highways