Car use decreases in U.S. cities with bike share systems, finds research

Bike share services are becoming more and more popular across the world, but one person’s spontaneous ride is another person’s commute to work, a study has highlighted. Prior to the COVID-19 pandemic, in cities where bike share systems have been introduced, commuting by cycling increased by an average of 20 per cent whilst car use decreased, said Dafeng Xu, an assistant professor in the University of Washington’s Evans School of Public Policy & Governance.

Xu studied U.S. cities with and without share systems, using Census and company data to analyse how commuting patterns change when the services become available. “This study shows that bike share systems can drive a population to commute by bike,” said Xu. 

Among other interests in transportation and immigration policy, Xu researches the effects of bicycling on the environment and human health, and on the ways bike share systems can play a role by expanding access to cycling.

“In general, biking is good and healthy, and it means less pollution and traffic, but it can be expensive, and people worry about their bikes being stolen, things like that,” Xu said. “Bike share solves some of these problems, because people don’t need to worry about the cost and theft.”

For this study, Xu sorted through nine years of demographic and commute statistics from the American Community Survey, an annual report by the Census Bureau. He then examined company data (through the National Association of City Transportation Officials) from 38 cities with systems, focusing on trips logged during morning and afternoon rush hours. By comparing the number, location and time of work-related bike commutes from Census data against company records of trips logged, both before and after the launch of the services, Xu was able to estimate the use of bike shares for commute trips.

Xu found that in both share and non-share cities, the rate of bike commuting increased, while car commuting decreased, from 2008-2016. However, the rate of bike commuting – and the use of public transportation – was significantly greater in bike-share cities.

For example, in bike share cities in 2008, approximately 66 per cent of commuters drove to work, about one per cent biked, and 22 per cent took transit. This is compared to non-bike share cities, where 88 per cent of commuters drove, fewer than one per cent biked, and four per cent took transit.

By 2016 – after many share systems had launched — car commuting had fallen to 59 per cent in these cities, while bike commuting had climbed to 1.7 per cent and transit to 26 per cent. Commuting by car in non-bike share cities had slipped to 83 per cent in 2016, while bike commuting had grown to one per cent, and transit to six per cent.

Divvy bike share, Chicago

In general, cities with larger bike share systems also experienced sharper increases in bicycle commuting, Xu said.

“This is not surprising: A large bike share system means a higher density of public bicycles and is thus more accessible by commuters,” he said. “In contrast, sadly, Seattle’s Pronto struggled to attract commuters and was finally doomed only after three years of operation partially due to its relatively small size.”

In his paper, Xu pointed to Chicago, which operates a municipally owned bike share system called Divvy. Prior to Divvy’s launch in 2013, 1.5 per cent of commuters biked to work, Xu said, but afterward, that rate grew to two per cent.

The trends held, he said, even when controlling for a city’s expansion of protected bike lanes – another significant factor in whether people choose to bike to work, according to other research.

Overall, the numbers before COVID-19 were promising, Xu said. The numbers could grow, he said, if communities and share companies make changes that can boost the appeal of bike commuting: adding bike lanes to city streets, expanding programmes to outlying communities, or increasing the allowable rental time. Many bike shares, for instance, last only up to a half-hour before a user has to pay for a new trip.