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35 range of physical conditions (including lack of sidewalk) that ence of trees). This makes it difficult to build statistically would not be easy to find in the field. robust models of LOS from the video laboratory data that The video lab approach also enabled testing of the signifi- accurately reflect the separate contribution of each correlated cance of demographics and metropolitan area on the percep- factor to a person's perceived LOS. Thus for Phase 2 it was tions of quality of service. recommended that the video clip library be expanded to in- clude a wider range of cases. 4.2 Phase I Data Collection Transit: The Phase 1 data collection effort obtained a (Pilot Studies) large amount of data (1,170 observations) for three urban areas (Miami; Portland; and Washington, DC). The re- During Phase I, the video lab method for gathering traveler search team noted that the specific routes surveyed in those quality of service ratings was developed and tested. A video metropolitan areas for Phase 1 did not exhibit significant lab approach for measuring auto level of service was tested by crowding at the dates and times of the surveys. This gap in George Mason University in Virginia. Sprinkle Consulting the transit data caused crowding to drop out as a significant tested a similar video laboratory approach for pedestrian level explanatory factor of transit LOS. Therefore it was recom- of service in Florida. mended that a few additional surveys be conducted in For the transit mode, a rider intercept approach for transit Phase 2 of more crowded bus routes with standees in one of level of service was tested in three metropolitan areas of the the metropolitan areas. United States (Ft. Lauderdale, Florida; Washington, DC; and Pedestrian: Eight video clips were developed and shown to Portland, Oregon). A total of 1,320 people were surveyed, and 45 participants in one metropolitan area (Sarasota, FL). 2,535 observations of quality of service were gathered during These clips, however, did not cover a very wide range of LOS Phase 1. Exhibit 36 provides key statistics on this Phase 1 data conditions (most being LOS C according to the FDOT collection effort. method). Thus the research team recommended that addi- The data gathered for each mode are summarized below. tional video clips of a wider range of conditions be obtained Auto: Fourteen video clips were developed and shown to for Phase 2. 75 research subjects in the Washington D.C. metropolitan Bicycle: No data collection was performed for bicycles in area. The results showed that a single factor, average travel Phase 1, so an entire new video clip library was developed for speed, explained 64% of the variation in LOS ratings reported Phase 2. by the laboratory participants. Comparison of the video lab perceptions to field percep- tions of LOS identified the same key factor influencing LOS 4.3 Development of Video Clips in the field (speed) as was found in the video lab. The corre- Auto Video Clips lation of the lesser factors to LOS varied between the field and the lab. The influence of other operational factors (signals Based on findings from Phase I, the most influential factors and stops), design, maintenance, and aesthetics on LOS was to driver perceived level of service were selected by the re- less pronounced in the field than in the lab. The one signifi- search team. These included in no particular order cant exception was pavement condition, which had a stronger influence in the field than in the lab (as expected, given that Presence of median (Yes/No); the video gives only a visual input on pavement condition, Landscaping (Yes/No); while the field gives both visual and tactile inputs). Progression (no progression is stopped at more than 50% The researchers noted that the limited number of video of signals); clips in the video library for Phase 1 resulted in some factors Posted speed (surrogate for arterial type); and being spuriously correlated (for example: speed and the pres- LOS depicted in clip using HCM methods. Exhibit 36. Phase 1 Data Collection Efforts. Number of Contractor Mode Method Metro. Areas Persons Data Points Cost GMU Auto Video Lab 1 75 975 $ 75,660 KAI Transit Field Intercept 3 1,170 1,170 $ 40,000 SCI Ped Video Lab 1 45 360 $ 30,500 Total Phase I 5 1,290 2,505 $ 146,160 GMU = George Mason University, KAI = Kittelson Associates, SCI = Sprinkle Consulting A data point is defined as one person providing an LOS rating for a single facility condition. Thus a person watching 10 video clips generates 10 data points.