One of the best illustrations of this is a fascinating study about police stops and sunset time. They were able to demonstrate that when the sun is up (i.e. the driver can be seen), black drivers are more likely to be pulled over, but when the sun goes down, it equalizes. As a bonus, they controlled for other factors by looking at these stats around when daylight savings switches.

https://engineering.stanford.edu/magazine/article/black-driv...

> First, they narrowed the range of variables they had to analyze by choosing a specific time of day — around 7 p.m. — when the probable causes for a stop were more or less constant. Next, they took advantage of the fact that, in the months before and after daylight saving time each year, the sky gets a little darker or lighter, day by day. Because they had such a massive database, the researchers were able to find 113,000 traffic stops, from all of the locations in their database, that occurred on those days, before or after clocks sprang forward or fell back, when the sky was growing darker or lighter at around 7 p.m. local time.

> This dataset provided a statistically valid sample with two important variables — the race of the driver being stopped, and the darkness of the sky at around 7 p.m. The analysis left no doubt that the darker it got, the less likely it became that a black driver would be stopped. The reverse was true when the sky was lighter.