Table 2 Data samples used throughout the analytic pipeline.

From: Unsupervised feature extraction of aerial images for clustering and understanding hazardous road segments

Locality

Image year selected for final analyses

# of segments used in training

# of segments used for feature extraction

# of segments after point reduction

# of hazardous road segments (> 3 RTCs)

Gloucester

2018

42,076

20,736

3,029

67

Cambridge

2020

32,022

15,676

2,776

129

Oxford

2019

33,207

17,142

3,154

138

Totals

107,305

53,554

8,959

334