A 2+1 road is a highway layout designed to improve safety on rural routes. It converts a standard two-lane road into a three-lane road. The center lane serves as a passing lane. It alternates direction every one to two miles. A steel cable barrier separates the directions to prevent head-on crashes. This design increases capacity and safety without the cost of a twin-carriageway.
Mechanic Glossary
2+1 Road
A three-lane road design where the center lane alternates as a passing lane for each direction, separated by a steel cable barrier.
Frequently Asked Questions
The steel cable barrier prevents head-on crashes, and the alternating passing lane stops drivers from passing into oncoming traffic.
Typically the same as a standard highway, around 55 to 65 MPH, depending on local regulations.
They can block traffic in the single-lane sections, but drivers can pass them safely once they reach the passing lane section.