Singapore study finds yellow taxis less accident prone than blue taxis

A trio of researchers affiliated with several institutions in Singapore, the U.S. and Hong Kong, has conducted a study examining the accident rates of blue versus yellow taxis being driven in Singapore and has found taxis painted yellow have lower accident rates. In their paper published in Proceedings of the National Academy of Sciences, Teck-Hua Ho, Juin Kuan Chong and Xiaoyu Xia describe their study, their results and why they believe there was a difference.

Though it may not seem like it, there are taxis painted colors other than yellow. In Singapore, there is a noticeable difference—one taxi company has a whole fleet of blue taxis and another yellow. This is because two companies merged many years ago and the resulting company chose to maintain the colors (drivers today drive both colors). Together the taxis make up approximately 60 percent of all cabs operating in Singapore. This, the researchers noted, provided an opportunity for testing the assumption that yellow cabs tend to be involved in fewer accidents.

To find out, the researchers studied three years of data from the company that owns the taxis—they found that yellow taxis had an accident rate 9 percent lower than blue taxis. This, they suggest, aligns with historical records from Chicago's Yellow Cab company, which was the first to deploy yellow painted taxis. They note that the company had worked with the University of Chicago back in 1907 to find out which color would be the best for helping potential customers spot a taxi amid a crowd of mostly back cars. They found back then that yellow was the easiest to see. The researchers suggest those earlier results likely explain their current findings—they believe other drivers on the road are better able to see the yellow cabs, and thus drive more carefully around them. They note this appeared to be especially true for vehicles driven at night.

The work might prove useful for the taxi company, as well—the researchers calculated that if the company painted all their blue taxis yellow, their cabs would be involved in 917 fewer accidents a year, saving the company approximately $1.4 million.

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