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5. Data Collection and Analysis
Pages 65-76

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From page 65...
... In March of 2020, it had become apparent that pandemic conditions would last longer than the intended time frame for data collection. A period of lockdowns followed by a long period of working from home led to a substantial reduction in traffic volumes across the United States.
From page 66...
... Heatmap showing distribution of data collection locations. 5.2 Data Analysis Because of the variety of cameras used across the various locations, the quality of the video collected for this research varied considerably among different locations.
From page 67...
... The original research plan had intended to employ machine learning-assisted analysis techniques to reduce the video and thereby obtain a larger quantity of video for a lower amount of effort. Unfortunately, much of the archived video did not have sufficient resolution to permit the use of automated techniques for counting individual movements and determining the signal states.
From page 68...
... Sample data from Gaines School Road and Cedar Shoals Drive, Athens, Georgia t R C RTOR V1R V2R LTR V3R P1R P2R RTOG V1G V2G LTG V3G P1G P2G 0 151 120 20 0 9 45 0 0 0 25 0 2 0 0 0 0 5 123 7 1 3 25 0 0 0 31 0 4 0 0 0 0 10 133 11 0 6 29 0 0 0 34 0 8 0 0 0 0 15 139 120 13 1 11 30 0 0 0 36 0 4 0 0 0 0 20 163 20 0 9 51 0 0 2 12 0 4 0 0 0 0 25 124 9 0 6 24 0 0 0 33 0 6 0 0 0 1 30 176 120 13 1 12 42 0 0 0 27 0 7 0 0 0 0 35 132 14 0 8 35 0 0 0 41 0 3 0 0 0 0 40 162 13 0 14 40 0 0 1 37 0 2 0 0 0 0 45 132 120 11 0 10 31 0 0 0 43 0 5 0 0 0 0 50 177 31 1 11 37 0 0 0 26 0 1 0 0 0 3 55 162 15 0 14 22 0 0 0 41 0 3 0 0 0 0 Note: t = start of 5-minute interval; R = total red duration in seconds; C = average cycle length in seconds; RTOG = right-turn-on-green. The rest of the notations are similar to those used in Figure 14.
From page 69...
... • Whether the intersection is in a central business district or similar area (such as a college campus) • Presence of median on crossing street • Subject and crossing approach speed limits • Presence of significant intersection skew A selection of site attributes is summarized in Figure 28.
From page 70...
... Interchange Yes No 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Bus Stops Yes No 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Lane Configuration Single Dual Shared 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Channelization Yes No 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Conflicting Thru Lanes One More than One 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Opposing Left Turn Lanes One More than One 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Receiving Lanes One More than One 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Shadowed Left Turn Yes No 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Right Turn Overlap Yes No 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Opposing Left Turn Protected Protected-Permitted Permitted 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Parallel Conflicting Pedestrian Crosswalk Both None 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Parallel Conflicting Bicycle Lane Both None 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Figure 28. Summary of site characteristics.
From page 71...
... . The mean RTOR volume is greater than the median for all three lane configurations.
From page 72...
... Figure 30 shows scatterplots of RTOR flow rate and total right-turn flow rate for different lane configurations. In all cases, there is an upward trend in the RTOR flow rate, as expected.
From page 73...
... RTOR flow rate versus total right-turn flow rate for different lane configurations. As discussed in the previous chapter, RTOR may occur during three different intervals within a cycle at a typical intersection.
From page 74...
... Figure 32. Total RTOR flow rate versus conflicting opposing left-turn flow rate.
From page 75...
... Total RTOR flow rate versus shadowed left-turn flow rate. Finally, the scatterplot of RTOR flow rate versus total pedestrian flow rate in Figure 34 shows a negative trend, since RTOR vehicles need to wait for pedestrians in the parallel and conflicting pedestrian crosswalks before executing the turn.
From page 76...
... 5.4 Conclusion This chapter presented the outcomes of the data collection and analysis activities undertaken during this study. Altogether, data from 260 locations across 25 states and the District of Columbia were assembled to support development of models of RTOR volume and capacity.


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