Traffic alerts within 1 km of GTH and RCP (Page 34)

To assess the quality of the routes computed by the geocoder, we compared our geocoded routes with ground truth data provided by the DTP through their website (DTP 2019). The Delhi Traffic Police (DTP) reported a set of 50 known point locations identified as traffic congestion hotspots across the Delhi–NCR region which we refer to as ground truth hotspots (GTH). We then plotted these on a map along with our weighted complex network (see Figure 8). To obtain a numerical comparison, we counted the number of tweeted traffic alerts within a 1 km buffer of each GTH (see Figure 8). Our hypothesis is that if geocoding is accurate, areas in the immediate proximity (&lt; 1km) of GTH should have higher counts as compared to areas further away (1-5 km). To test this hypothesis, we randomly sampled 50 random control point locations (RCP) in the Delhi-NCR and computed the number of traffic alerts within a 1 km radius of those.<br>An independent-samples Welch’s t-test was used to compare the mean number of traffic alerts within a 1 km buffer of GTH and RCP sites. GTH sites (mean = 102, sd = 124, N = 50) recorded significantly more alerts than RCP sites (mean = 33, sd = 111, N = 50). The mean difference of 69 (SE = 24) was statistically significant, <i>t</i>(96) = 2.92, <i>p</i> = 0.0044, with a 95% confidence interval ranging from 22.00 to 115. The results indicate that traffic alert density is substantially higher (at least 22 more alerts on average at the 95% confidence level) around GTH sites compared to randomly selected control areas. This serves as statistically significant evidence to support the hypothesis that geocoding results accord spatially with ground truth data.