Managed lanes

A managed lane is a type of highway lane that is operated with a management scheme, such as lane use restrictions or variable tolling, to optimize traffic flow, vehicle throughput, or both. Definitions and goals vary among transport agencies, but managed lanes are generally implemented to achieve an improved operational condition on a highway, such as improving traffic speed and throughput, reducing air pollution, and improving safety. Types of managed lanes include High-occupancy vehicle (HOV) lanes, High-occupancy toll lanes, express toll lanes, reversible lanes, and bus lanes. Most managed lane facilities are located in the United States, although HOV and bus lanes can be found in many other countries; outside of the US, many countries use active traffic management that manage all lanes of a highway.

The definition of a managed lane varies among transport agencies. The United States' Federal Highway Administration describes managed lanes as "highway facilities or a set of lanes where operational strategies are proactively implemented and managed in response to changing conditions". The FHWA notes that among US transport agencies, definitions of managed lanes contain three basic elements:

The Texas Department of Transportation defines a managed lane as "one that increases freeway efficiency by packaging various operational and design actions. Lane management operations may be adjusted at any time to better match regional goals." Typical goals and objectives for managed lanes are improved traffic efficiency, increased traffic throughput, improved safety, and reduction of pollution to meet regional air quality goals.

If designed to improve travel conditions on a highway, the following types of lanes can be considered managed lanes: High-occupancy vehicle (HOV) lanes, tolled lanes built within or along an existing highway (express toll lanes), high-occupancy toll (HOT) lanes, reversible lanes (British: tidal flow), truck lanes, interchange bypass lanes (usually for HOV, truck, or mass transit only), bus lanes, use of shoulders by traffic in certain circumstances (dynamic shoulder lanes), and dual/parallel highways of which one is managed.

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