Purpose of the Screening and Evaluation Process
 The purpose of the screening and evaluation process is to quantify, measure and comparatively evaluate how the alternative strategies approved by the OCTA Board in March 2009 perform when modeled in 2035 central Orange County.
The screening and evaluation process helps identify which alternative strategy, or combination of alternative strategies, are most likely to:
- meet projected travel demand
- improve mobility, particularly in the north/south direction
- relieve traffic congestion
- offer cost/benefit value
Similarly, screening and evaluation helps indicate which alternative strategies are least likely to address future transportation needs.
Ultimately, screening and evaluation results provide policy-makers the performance data and cost/benefit/impact information they require to debate, define and adopt a locally preferred strategy (LPS) for central Orange County.
Locally Preferred Strategy – A Policy Decision
It is important to note that the selection of an LPS is a policy decision informed, but not necessarily defined, by technical results and recommendations. As policy-makers, the PAC and OCTA Board have full discretion to weigh non-technical considerations and issues in formulating and approving an LPS.
Overview of Screening and Evaluation
The screening and evaluation process takes place in two (2), increasingly rigorous and competitive stages.
Currently underway, Stage #1 is expected to be completed in late Summer 2009. Subject to Board approval, Stage #1 will produce a recommended reduced set of alternative strategies. It will also provide very preliminary insight into costs and potential right-of-way needs associated with strategic concepts.
If and when approved by the Board, this reduced set of alternative strategies will, in turn, be more rigorously evaluated in Stage #2. When concluded, Stage 2 is expected to produce a recommended LPS by mid-2010.
Stage #1 – Schedule and Objectives
Stage #1 will take place from April 2009 to August 2009. During Stage #1, all fourteen (14) alternative strategies approved by the Board will be screened and/or modeled.
Stage #1’s key objective is to efficiently and cost-effectively identify which of the initial alternative strategies meets a minimum level of performance and which do not.
Capacity Assessment and Simulated Modeling
To make this determination, the study team will first conduct a capacity assessment to determine a minimum number of performance attributes.
Secondly, the study team will use computer modeling technologies to model and measure how the fourteen (14) alternative strategies perform in simulated 2035 conditions.
Performance Indicators/Measurements
Several key performance indicators will be measured during modeling, including:
- Vehicle Hours of Delay (VHD)
- Changes in Vehicle Miles Traveled (VMT)
- Changes in Average Speeds by Facility (Streets v. Freeways)
- Ridership Estimates (R/E)
- Volume/Capacity Ratios (V/C)
- Travel Demand
Stage #1 Results and Next Steps
When Stage #1 is completed, the study team anticipates that it will be able to report whether alternative strategies had a positive, negative or neutral impact on the performance indicators. The study team will also be able to identify preliminary cost/benefit differences between the alternatives strategies.
Ultimately, the PAC and Board – after receiving input from the Technical Working Group and feedback from the Stakeholder Working Group – will recommend a reduced set of alternative strategies for more in-depth and rigorous screening in Stage #2.
Stage #2 - Overview and Objectives
Currently, Stage #2 is estimated to begin in late Fall/early Winter 2009.
Like the first stage, Stage #2 will use computer modeling and forecasting technologies to quantify and measure performance between the reduced set of alternative strategies.
However, Stage #2 will be more in-depth, focusing on:
- Performing more rigorous simulation and modeling runs
- Conducting detailed comparative analysis and evaluations
- Analyzing levels of investments and return
- Identifying high performing elements, trends and/or combinations of alternative strategies
When completed, Stage #2 will provide a relatively clear and wide-ranging menu of transportation concepts to help meet travel demand in central Orange County.
At this time, it is estimated that Stage #2 of the screening and evaluation process will be completed in early 2010.
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