SINGAPORE ROAD SPEED · KEY FINDINGS
A saved day of Singapore traffic data gives a speed band (a speed range, from band 1, under 10 km/h, to band 8, 70 km/h and above) for each of road links every five minutes: 288 readings per link. Which links follow a similar speed pattern through the day, and where are they?
UMAP turned each link’s 288 readings into two coordinates, so every link became a dot on a 2-D chart, called an embedding, with similar daily patterns close together. K-means then split the dots into clusters. The bands were used as they are, without subtracting each link’s average (no mean-centring), so a cluster reflects both how fast its links are and how their speed changes through the day. Clusters are numbered 0–99 and coloured from blue (slowest) to red (fastest) by their average band from 12:00 to midnight; cluster 0 holds the 32 links with no readings.
How to read the figure. In “UMAP embedding”, each dot is one road link. Move the pointer over the chart to highlight the cluster whose centre is nearest; the same cluster lights up in the other two panels. Click to pin it, and click it again to release it. “Cluster’s daily profile” shows that cluster’s average band through the day, with a shaded band of ± one standard deviation. “Road links on the map” puts every link at the midpoint of its two ends: scroll to zoom, drag to pan, and hover over a dot to see its road name, LinkID and cluster; clicking a dot pins its cluster, and clicking empty map releases it. Color points by can instead colour every link by its average band in one two-hour window, which the profile panel then shades. Inspect cluster picks a cluster by number.
Saved reference · statistics verified from CSV