Yellow taxis involved in fewer accidents than blue ones: NUS study

SINGAPORE — Taxis painted yellow are 9 per cent less likely to be involved in an accident compared to those coloured blue, according to a study by National University of Singapore (NUS) researchers.

Analysing 36 months of taxi, driver and accident data from ComfortDelGro’s fleet of 4,175 yellow taxis and 12,525 blue taxis, they found that yellow taxis had 6.1 fewer accidents per 1,000 cabs per month compared to the blue ones, mainly because of the difference in their visibility.

Under street lighting, yellow taxis were 19 per cent less likely to be rear-ended than blue cabs. The difference is slighter in the day, with yellow taxis 5 per cent less likely to be rear-ended.

The researchers believe that if ComfortDelGro changes its entire fleet to yellow, there could be 76.4 fewer accidents per month, or 917 fewer accidents per year. 

Assuming an average repair cost of S$1,000 per car and a downtime of 6 days, ComfortDelGro could save up to S$2 million annually, they added.

ComfortDelGro, Singapore’s largest taxi operator, has about one yellow taxi for every three in blue.

In response to media queries, ComfortDelGro Corporation’s group communications officer Tammy Tan said: “The findings by the recent NUS study are very interesting, and we will certainly take a closer look at it.”

The NUS study was published in the scientific journal, Proceedings of the National Academy of Sciences (PNAS), and posted online on Monday.

PNAS is one of the world’s most-cited scientific journals, publishing more than 3,100 research papers annually.

The researchers said their findings “can play a significant role when choosing colours for public transportation and may save lives as well as millions of dollars”. 

To rule out differences in driving patterns, they used GPS data from the taxis to measure driving speeds, number of stops and distance covered. They also compared three demographic factors that might be related to driving skill— age, education and experience.

No statistically significant differences were observed, the researchers noted, leaving the colours of the cabs as the only differentiator. 

The study was led by Professor Ho Teck-Hua, a behavioural scientist and deputy president (Research & Technology) at NUS. The other two co-authors are associate professor Chong Juin Kuan from the NUS Business School and assistant professor Xia Xiaoyu from the Chinese University of Hong Kong Business School.