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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