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The modelers were able to calibrate the three tools to baseline conditions on both the I-5 and I-210 freeways. The C11 tool could be calibrated by adjusting the capacity and changing the demand-by-hour distribution to match the facility distribution of volume by hour. The L07 tool could be calibrated using the same levers. The FREEVAL-RL tool was much harder to calibrate to baseline conditions, due to an inability to handle limited-access high-occupancy vehicle lanes and significant congestion along the facility that exceeded the maximum extent and duration supported in FREEVAL-RL. None of the tools produced results that could be used directly in benefit-cost analysis, but each could be do so with minor adjustments: ⢠The C11 tool estimates benefits for the current year and a future year, but it does not estimate life-cycle benefits over a given time period. These can be approximated by interpolating and discounting the current and future year benefits outside the model. ⢠The L07 tool estimates life-cycle benefits by estimating benefits for the current year and assuming these benefits are constant over the life cycle. The tool needs to be modified to accommodate demand growth. ⢠The FREEVAL-RL tool does not estimate monetized user benefits using the reliability results. However, these could be calculated from the travel time reliability performance measures (i.e., standard deviation or 50th and 80th percentile TTI) and vehicle-miles traveled (VMT) data outputted by the model. Decision Maker Perceptions SCAG and Caltrans representatives agreed that considering reliability in the decision-making process would be an important step forward, particularly since project selection decisions in Southern California have been influenced by environmental and sustainability considerations in recent years. Although measures of mobility and asset condition continue to influence decision making, other factors such as vehicle-miles traveled (VMT) per capita and greenhouse gas (GHG) emissions have been added to the list of factors considered. California state law (SB 375 and AB 32) now requires regional agencies to demonstrate that their regional transportation plans (RTPs) reduce GHGs per capita. Specific thresholds are defined by the California Air Resources Board, and regional agencies have to develop a sustainable community strategy that incorporates smart growth along with the RTP. Large expansion projects that encourage more driving are difficult to implement in this policy environment. Therefore, using reliability to make operational projects more visible to policy makers was encouraged by regional stakeholders. In reviewing the findings from the SHRP 2 products, the reliability results were consistent with agency expectations. SCAG and Caltrans representatives reacted positively to the CDF graphs and percent contribution tables as ways to summarize factors contributing to reliability. Representatives from both agencies noted that the SHRP 2 products would be useful 11
