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Table 2 Validity of GigaPan® and Google Earth technology in comparison to direct observation for all traffic and safety categories for street segments in Pittsburgh, PA

From: Validity of environmental audits using GigaPan® and Google Earth Technology

Variable N Prevalencea Gigapan® versus direct observation Google Earth versus direct observation
Sensitivity 95% CI Specificity 95% CI Sensitivity 95% CI Specificity 95% CI
Number of lanes of trafficb 464 81.3 83.0 (78.8, 86.7) 56.3 (45.3, 66.9) 85.9 (82.0, 89.3) 57.5 (46.4, 68.0)
Street type 462 05.8 59.3 (38.8, 77.6) 98.9 (97.3, 99.6) 66.7 (46.0, 83.5) 98.4 (96.7, 99.4)
Special speed limit 457 02.6 16.7 (02.1, 48.4) 99.6 (98.4, 99.9) 41.7 (15.2, 72.3) 98.2 (96.5, 99.2)
Curb 463 80.1 95.1 (92.4, 97.1) 79.3 (69.6, 87.1) 97.0 (94.8, 98.5) 82.6 (73.3, 89.7)
Street or sidewalk lighting 459 95.6 90.9 (87.8, 93.4) 65.0 (40.8, 84.6) 88.2 (84.8, 91.0) 75.0 (50.9, 91.3)
Sidewalk 457 80.1 97.0 (94.7, 98.5) 82.4 (73.0, 89.6) 98.1 (96.1, 99.2) 82.4 (73.0, 89.6)
Street and sidewalk buffer 350 39.1 70.1 (61.7, 77.6) 79.8 (73.8, 85.0) 78.1 (70.2, 84.7) 72.3 (65.8, 78.2)
Continuous sidewalk 351 96.6 90.9 (87.3, 93.7) 00.0 (00.0, 26.5) 87.6 (83.6, 90.9) 33.3 (9.9, 65.1)
Continuous sidewalk both ends 350 96.6 69.8 (64.6, 74.7) 75.0 (42.8, 94.5) 78.4 (73.6, 82.7) 83.3 (51.6, 97.9)
Traffic light 462 18.2 79.8 (69.6, 87.7) 97.4 (95.2, 98.7) 92.9 (85.1, 97.3) 98.4 (96.6, 99.4)
Ped. signal at traffic light 462 06.5 53.3 (34.3, 71.7) 97.7 (95.8, 98.9) 73.3 (54.1, 87.7) 98.1 (96.4, 99.2)
Stop sign 459 39.4 79.0 (72.3, 84.7) 91.7 (87.8, 94.7) 86.2 (80.3, 90.9) 92.1 (88.3, 95.0)
Children/special pop sign 461 05.0 13.0 (02.8, 33.6) 98.9 (97.4, 99.6) 34.8 (16.4, 57.3) 97.9 (96.1, 99.1)
Marked bike lane 462 03.7 52.9 (27.8, 77.0) 99.6 (98.4, 99.9) 47.1 (23.0, 72.2) 99.8 (98.8, 100)
Marked crosswalk 459 32.7 56.0 (47.7, 64.1) 92.9 (89.4, 95.5) 72.0 (64.1, 79.0) 93.9 (90.6, 96.3)
Median with traffic island 463 02.4 63.6 (30.8, 89.1) 100.0 (99.2, 100) 63.6 (30.8, 89.1) 100 (99.2, 100)
  1. Non-overlapping 95% confidence intervals for GigaPan® and Google Earth sensitivity/specificity are in italic
  2. CI confidence interval, Ped. pedestrian, Pop population
  3. aPercentage of segments with attribute, as determined by direct observation audit
  4. bLanes of vehicular traffic was categorized into one or fewer traffic lanes versus more than one traffic lane