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⢠It would be very useful for the model documentation to provide examples of model networks. ⢠The documentation should provide information on how FREEVAL-RL develops different scenarios during the scenario runs. ⢠The current version of the manual states that the user needs to run the seed file to generate scenarios and then run scenarios. However, the manual should refer to the results file from the seed file rather than the seed file itself. ⢠The manual should document known model limitations and workarounds. For example, the HCM 2010 does not support on-ramp segments with more than two on-ramp lanes and six mainline lanes. 7.3 Base Model Development Study Site The study team originally intended to test the FREEVAL-RL tool for both the I-210 and the I-5 facilities. However, after encountering setbacks due to the model limitations described above, the team decided to limit the model testing to only the I-5 facility. Even in this case, the team could not model the entire facility, because FREEVAL-RL has a limit on the number of segments included in an individual model, and the overall facility must start and end in free-flow conditions. After analyzing the existing congestion on the facility relative to FREEVAL-RL model limitations, the study team decided to develop a northbound (NB) for the a.m. peak period and a southbound (SB) model for the p.m. peak period. As shown in Figure 7.2, the northbound model extends from the State Route 1 (SR-1) on-ramp (postmile 79.1 or p.m. 79.1) to the Alton off- ramp (p.m. 93.7). The southbound model extends from the Jamboree on-ramp (p.m. 99.62) to the Crown Valley off-ramp (p.m. 86.18). The study periods are from 6:00 to 10:00 a.m. for the a.m. model and from 3:00 to 8:00 p.m. for the p.m. model. The boundary limits of the two models are located in free-flow areas at the beginning and ending of each analysis time interval. 138
© Google Maps (a) NB model coverage ©Google Maps (b) SB model coverage Figure 7.2. Coverage of northbound and southbound I-5 models. Source: Google Maps. google.com 139
Geometric Data Preparation The study team obtained geometric data for both FREEVAL-RL models from a Paramics microsimulation model developed earlier for the I-5 CSMP. The I-5 Paramics model covered a portion of the freeway from the San Diego county line (p.m. 73) to the Chapman interchange, which is north of the SR-55 interchange (p.m. 107). Having the geometry data already available from the microsimulation model saved the team from extensive data collection and field visits. Even so, the study team had to verify some distances using Google Earth, since the model geometry in the microsimulation model did not correspond exactly to the FREEVAL-RL model requirements. Table 7.1 provides an example of the data extracted from the Paramics model for the northbound model. As can be seen in the table, this information included the number of lanes, length of each segment, and the starting and ending point for each segment. Table 7.1. Example of Extracted Geometry Data for Northbound I-5 Model Start End type #Lanes Length (ft) Crown Valley On 1 Crown Valley On 2 ML 4 1607.9 Crown Valley On 2 Oso Pkwy Off ML 5 4015.7 Oso Pkwy Off High-Occupancy Vehicle Start ML 4 296.8 High-Occupancy Vehicle Start High-Occupancy Vehicle End ML 5 1221.5 High-Occupancy Vehicle End Oso Pkwy On1 ML 4 456.3 Oso Pkwy On 1 Oso Pkwy On2 ML 4 1311.2 Oso Pkwy On 2 La Paz Off ML 4 4302 Segment Type Determination Based on its understanding of FREEVAL-RL segment type definitions from the FREEVAL-RL manual and related chapters of HCM 2010 (ITRE and CMT 2011), the team converted the geometric data into a format that could be used in the model. Table 7.2 provides an example of the geometric data inputted into FREEVAL-RL. Unfortunately, the segment definitions in FREEVAL-RL required the study team to collect additional data not available in the microsimulation model. The team obtained acceleration and deceleration lengths for each on- ramp and off-ramp through Google Earth. 140
Table 7.2. Example of Southbound I-5 Geometric Data for FREEVAL-RL Segment Number 1 2 3 4 5 6 7 Segment Starting Point JamborreeOn2 Culver Off After HOV_End_500ft CulverOn1 CulverOn2 Segment Type B OFR W B ONR ONR B #Lanes 6 6 6 5 5 5 5 Length (ft) 1087.4 1500 1938.5 152.8 1246.3 1500 4127 Acc/Dec Length 217.8 285.7 The study team paid careful attention to determining the segment type based on its understanding of HCM 2010. FREEVAL-RL is designed to analyze the freeway mainline. However, many freeways in California have a parallel high-occupancy vehicle facility, which may be limited-access or continuous-access. For the limited-access high-occupancy vehicle lane along I-5, there is an ingress/egress area where high-occupancy vehicle drivers can change lanes. According to the developer of FREEVAL-RL, the tool does not support any managed lane evaluation. The study team conducted extensive evaluations to find possible solutions that would allow FREEVAL-RL to model the high-occupancy vehicle ingress and egress areas. Table 7.3 summarizes the number of segments by type for the two FREEVAL-RL models developed for the I-5 facility. For the NB model, there are 59 segments, including 10 weaving segments (Type W), 16 basic segments (Type B), 15 on-ramp segments (Type ONR), 14 off- ramp segments (Type OFR), and 4 overlapping ramp segments (Type R). For the SB model, there are 51 segments, including 12 weaving segments (Type W), 13 basic segments (Type B), 16 on-ramp segments (Type ONR), 9 off-ramp segments (Type OFR), and 1 overlapping ramp segment (Type R). Table 7.3. Number of Segments by Type in I-5 Models Segment Type NB Model SB Model B 16 13 R 4 1 W 10 12 ONR 15 16 OFR 14 9 Total 59 51 141
