Crunching some numbers on Paris bike-sharing program
On the first anniversary of Vélib, the Times dishes up some stats on Paris’ popular bike-sharing program:
* Riders took 27.5 million trips in the first year.
* The current pace is about 120,000 trips per day.
* The program includes 20,600 bikes.
* The 1,450 self-service rental stations are available every 300 yards.
* The bikes are heavy and expensive — $3,460 and 50 lbs — built to withstand theft, mistreatment, and heavy riding.
* Nevertheless, 3,000 bikes have gone missing, about 15% of the total.
Such programs, done right, do a fantastic job of boosting bicycle ridership. One thing they don’t necessarily do, however, is reduce a lot of carbon emissions. I built a simple model using the cited figures, and added in assumptions about average trip length, the number of displaced car miles, average fuel efficiency, etc. The results are necessarily rough, but I estimate the program is currently reducing maybe 40,000 metric tons of CO2 per year, about the amount saved by removing 5,700 cars from the road. (This suggests that it takes about 3.6 shared bicycles to replace a car.)