Operational Criteria

The operational characteristics of a corridor are all the physical features and modes of transportation found along it. Typical elements include:

Corridor Length

The generic corridor is approximately ten to twenty miles in length and roughly linear. It consists of a freeway, parallel arterials, and transit (bus, heavy rail, light rail, and water transit; or a combination of those transit types). Additionally, it is a commuter route, may have employment sites or business parks, a nearby airport, a sports or event stadium, schools, retail, a central business district, and/or residential neighborhoods.

Congestion

A congested corridor is key, as ICM improvements can reduce corridor congestion. High levels of congestion in the corridor mean loss of personal and/or professional time, environmental impacts (fuel consumption and emissions), and traveler dissatisfaction. Congestion in the corridor causes delays and bottlenecks. Travel reliability and travel time fluctuations are impacted by the sheer number of cars in the corridor and an increase in accidents. Corridor selection can consider freeway and/or arterial accident/incident history.

Freeway

Three to four travel lanes in each direction with one lane designated as a high-occupancy vehicle (HOV) lane during peak hours or 24 hours per day, or a high-occupancy toll (HOT) lane, with shoulders and metered ramps on all or a portion of the freeway. The freeway should be instrumented and have data available (such as PeMS or mobile probe data). The freeway will have recurrent, severe congestion and bottlenecks due to commute traffic as well as non-recurrent traffic due to incidents or events.

Arterials

One or two arterial networks on either side of the freeway, with timed signals approximately one-half mile apart, at least two travel lanes in each direction, and no on-street parking. It's best if the arterials are instrumented. One ICM strategy is to reroute traffic from the freeway to the arterial(s) or from an arterial to a freeway in case of an event or incident.

Rail

One light rail track in each direction paralleling the freeway or in the freeway median, heavy rail in the corridor for intercity service (likely will also serve freight), stations located throughout the corridor, and parking facilities at the stations and/or park-and-ride lots.

Bus

Regional or rail-serving bus service on the freeway in the HOV lanes, local bus service on the arterials, Bus Rapid Transit or express bus service (timed transfers and “next bus” technology at the bus stops), parking or park-and-ride lots at bus hubs.

Questions to Ask

Assessing the physical and technical attributes of a corridor is fundamental in determining its suitability for an ICM project. Here are some basic operational questions to consider when choosing a site:

Is there at least one freeway and one parallel arterial? This is the minimum configuration that must be present when considering a corridor.
Is it a highly congested freeway and arterial? The goal of an ICM project is to reduce congestion and improve mobility along a corridor.
Is fiber available? How highly instrumented is the corridor? An ICM project requires traffic data for the various elements of the corridor. Is the infrastructure available for gathering the sensor data needed for the project?
Do the arterials have signal timing? The ability to time signals along arterials is important for improving traffic flow and accommodating overflow traffic from the freeway.
Is the corridor multi-modal? Additional transit modes (bus, rail, etc.) create more options for both travelers and traffic flow along the corridor.
What adjacent uses are there along the corridor (retail, employment, airport, schools, etc.)? The adjacent uses can identify trip generators and patterns of congestion.
Is there opportunity for replicability around the state and nationally? Are the corridor's characteristics representative enough to make its study useful for other corridors? Does the corridor have special or unique features that make it difficult to apply the lessons learned to other situations?