Congestion Management System

Chapter 5: CMS Monitoring Plan

The Congestion Management System must be continually updated and monitored to (1) determine if enhancements are needed to the plan, (2) to track the effectiveness of the CMS recommendations over time, and (3) to determine the necessary data collection efforts needed to support the CMS. This plan will identify in Chapter 6, the needed enhancements and considerations for future CMS planning efforts. Effectiveness tracking and data collection needs will be defined in more detail in this section.

5.1: Effectiveness Tracking
The effectiveness and implementation status of all recommendations made in this report will be continually monitored, and information provided on a regular basis through a “CMS Update” report. As projects identified by the CMS are implemented, it will be necessary to devise an appropriate methodology to identify the effectiveness of each one. This will require different methodologies for each type of strategy, and data collection to support that analysis. A summary of preliminary methodologies for assessing the effectiveness of each congestion mitigation strategy proposed in Chapter 4 is given in Table 5-1 below:

 

TABLE 5-1: Preliminary Measures of Effectiveness by CMS Strategy

Strategy Class	Preliminary Measures of Effectiveness
1 - Travel Demand Management	VMT Growth, Vehicle Occupancy Rates, Travel Demand Model Scenarios
2 - Traffic Operational Improvements	Travel Time Studies, Delay Studies
3 - Public Transportation Improvements	Transit Ridership Levels, Travel Demand Model Scenarios
4 - Intelligent Transportation Systems	Travel Time Studies, Travel Demand Model Scenarios
5 - Additional System Capacity	Travel Time Studies, Volume-to-Capacity Ratio

 

It will be important to require the consultant or implementing agency that is responsible for the design of the various improvement projects to assess its effectiveness whenever possible to lessen the burden of the amount of data collection and analysis that will be required by TPO staff. An example of this would be the situation where traffic signals are re-timed along a corridor, and the consultant responsible for developing the timing plans would be required to do a before and after analysis as part of the contract to determine the travel time reduction post-implementation. The long timeframe that some of the strategies require for full implementation, such as a roadway reconstruction project, will present a challenge in being able to assess the effectiveness of the strategy. Construction will also affect the analysis of strategies that are being “overlaid” on one another, For example if ITS strategies are being implemented on a corridor that is already under construction for roadway widening then it will be difficult to assess the amount of travel time savings that is attributable to each strategy.

5.2: Data Collection Activities
The current data collection activities that were performed in support of the current CMS plan will be continued, as well as any enhancements that are defined at a later date. The data collection effort is rather large and time-consuming; therefore the corridors will be placed into different priorities based on their level of congestion. The following data collection activity schedule is being proposed initially, with future modifications as deemed necessary:

• Traffic Count Data – Continue on-going program of traffic count data collection, expanding as necessary. Used to monitor when a roadway meets the threshold for inclusion in the CMS process.
• Travel Time Data – The travel time data collection program using GPS units will continue with minor modifications. The analysis period will be investigated to determine whether the true peak hour is being captured. Also, the roadways not currently meeting the congested criteria will be split into two groups and run every other year instead of yearly, which will be the case for the congested corridors. Exceptions may be made for facilities that are under construction, which will disrupt the travel time data.

5.3: Regional Transportation Demand Modeling
As will be discussed in the “Future Considerations” chapter, it is desired to use a travel demand forecasting model approach to project future congestion, and to assess the benefits of a particular congestion mitigation strategy. A consultant has been selected to prepare an updated model for the TPO, with CMS data needs and monitoring playing a role in determining the make-up of that model. The “EVE” process will most likely be replaced entirely by the new model.