Congestion Management Process (CMP)
An efficient transportation system is reflected by the ability to travel with a minimum of delay. Factors influencing delay are the capacity of the system, operational characteristics, and the amount of demand during a given period of time. The various causes of congestion, sometimes occurring in combinations, have been categorized as follows:
- Bottlenecks or Choke Points– Usually a reduction in the physical capacity of the roadway (the number and width of lanes and shoulders; merge areas at interchange ramps; and roadway alignment (grades and curves).
- Incidents –Events such as vehicular crashes, breakdowns, and debris in travel lanes are the most common forms of incidents. As part of the process to help manage incidents, TRIMARC has instituted a notification service that will help to let anyone who signs up for the service know of major incidents and road closures. The website is the NET (Notify Every Truck). This website notifcation is free.
- Construction Work Zones – Locations where construction activities on or near the roadway result in reductions in posted speed limits, the number or width of travel lanes, lane "shifts," lane diversions, reduction, or elimination of shoulders, and even temporary roadway closures.
- Inclement Weather – Rain, snow, ice, wind, or other environmental conditions that can lead to changes in driver behavior that affect traffic flow.
- Traffic Control Devices – Intermittent disruption of traffic flow by control devices, such as railroad grade crossings and poorly timed signals, also contribute to congestion and travel time variability.
- Special Events – Are a special case of demand fluctuations whereby traffic flow in the vicinity of the event will be radically different from "typical" patterns. Special events occasionally cause "surges" in traffic demand that overwhelm the system.
- Fluctuations in Normal Traffic – Day-to-day variability in demand leads to some days having higher traffic volumes than others. Varying demand volumes superimposed on a system with fixed capacity also results in variable (i.e., unreliable) travel times.
Congestion management is the application of strategies to improve transportation system performance reliability by reducing the adverse impacts of congestion on the movement of people and goods where possible and desired. A Congestion Management Process (CMP) is a systematic and regionally accepted approach for identifying and managing congestion to provide accurate, up-to-date information on system performance and to assess alternative strategies for congestion management that meet state and local needs.
A CMP is federally required under 23 CFR 450.322 of the Fixing America’s Surface Transportation (FAST) Act in metropolitan areas with a population exceeding 200,000, known as Transportation Management Areas (TMAs). The Louisville/Jefferson County KY-IN Metropolitan Planning Area (MPA) qualifies as a TMA. Federal requirements also state that, in all TMAs, the CMP shall be developed and implemented as an integrated part of the metropolitan transportation planning process. In TMAs designated as ozone or carbon monoxide non-attainment areas, the CMP takes on a greater significance. Federal law prohibits some projects resulting in a significant increase in carrying capacity for single occupant vehicles (SOVs) from being programmed in these areas unless the project is addressed through the region‘s CMP.
As part of the CMP, congestion management strategies are identified, assessed, programmed, implemented, and evaluated for effectiveness. The process through which this is accomplished consists of the activities listed below. Inherent in this process is the ability to update the CMP in conjunction with other elements of the overall metropolitan transportation planning process.
- Establishing regional objectives
- Defining the CMP Network
- Establishing performance measures
- Identifying sources and methodology for data collection
- Identifying congestion
- Developing congestion mitigation strategies
- Reviewing strategy effectiveness
The CMP was first implemented in 1999, updated in 2006 and amended in 2011. The current CMP was developed and approved by KIPDA’s Transportation Policy Committee (TPC) in July 2018.
Congestion Management Process for Louisville (KY-IN) Metropolitan Planning Area
Posted 8/8/18, PDF, 4MB
Map of the CMP Network
Posted 8/8/18, PDF, 489 KB
Map of TAD Congestion Zones
Posted 8/8/18, PDF, 461 KB
Intelligent Transportation Systems
TRIMARC -Incident Management and Itelligent Transportation for the Metropolitan Planning Area