Managed lane

The most important prerequisite condition necessary for managed lane demand to materialize is the presence of recurring traffic congestion.

These situations generally correspond to a level of service of D or worse (on a scale A-F, with A being highest) and average travel speeds of 30 mph or less, although this does not mean that other scenarios are not suitable for managed lane strategies.

[4] The specific characteristics of the traffic demand that exists in a corridor are particularly important when considering managed lane strategies.

These patterns cause an imbalance of demand that require solutions that are flexible in their ability to accommodate variable and directional traffic volumes.

Routes that connect suburban trips may exhibit bi-directional demand and be congested for more prolonged periods, so the selected concept needs to recognize this.

Agencies often combine lane management strategies and applications of various intelligent transportation systems (ITS) and traffic control devices to address both safety and operation needs.

For example, restricted lanes for buses and carpools only make sense and draw sufficient patronage when parallel programs including transit services, park-and-ride / park-and-pool lots and trip matching are implemented.

Ramp and connector metering offers the opportunity to provide bypass lanes for transit and other transportation modes to attract demand.

For example, highly directional congestion (i.e., inbound in the morning and outbound in the evening) may be addressed by a variety of different treatments such as concurrent, reversible or contraflow operations, and each will require a different design that may or may not fit within the corridor.

ETLs are essentially access restricted tollroads within the freeway right-of-way that are actively managed to preserve free-flow operating conditions.

In such highway reconstruction projects, the government transport agency tenders a P3 project in which a private consortium of companies designs, finances, and rebuilds a section of highway after which they are given a concession (e.g. 40 years) to operate the toll managed lanes, receiving fixed payouts from the relevant government transport agency for meeting performance criteria.

This is accomplished by providing travel time savings and reliability for high occupancy modes to incentivize carpooling and the use of transit.

Some HOV lanes are reversible to serve directional demands at different times of the day; these facilities are separated by a permanent barrier and are accessed via exclusive ramps.

However, there is a distinction between a lane dedicated to exclusive use by buses and BRT, which may include various operational improvements and station design features to provide high quality service for express bus trips.

Although the Transitway serves all types of HOVs and will soon incorporate solo vehicle pricing, it includes several sections where bus-only lanes and separate roadways into stations for buses exist.

[4] Some cities may have transit ways that are completely built from the start to be dedicated only to buses, such as the Mississauga Transitway near Toronto, Canada.

One example is the New Jersey Turnpike, the northern portion of which features completely separated dual roadways, one reserved for passenger cars only, and the other open to both commercial and non-commercial traffic.

Climbing lanes for trucks typically are built to improve safe operations on grades by separating slow moving heavy vehicles from the rest of traffic.

If such is the case, then some users, such as deadheading transit buses that need trip reliability to make a second peak direction run during the commute period, will be adversely impacted.

Freeway reversible lanes often can be separated by "Jersey" barriers in a high-speed roadway setting (which is not the case on arterial treatments).

Reversible lanes offer a much higher guaranteed level of service for transit since side friction from adjacent traffic is removed.

Adapting a reversible flow lane or roadway into a freeway typically requires rebuilding most bridges with center columns.

Management and enforcement is made easier by the barrier environment in which a single field location can be identified to monitor and/or toll all traffic flow.

In the Seattle area, the right shoulder on the US 2 trestle near Everett is opened to all traffic in the eastbound direction during the afternoon peak period.

Early implementations of bus-only use of shoulders in the region were limited to arterial roads, but the concept was soon expanded to freeways after they were shown to be safe and hugely successful.

[4] A similar law was passed in Colorado in early 2016 for the RTD Flatiron Flyer bus route on U.S. 36 along the Denver-Boulder corridor.

This article incorporates public domain material from Efficient Use of Highway Capacity Summary: Report to Congress (Chapter 2: Context and Findings; May 2010).