Just to add something to this story about bikeshare rebalancing. Emily Badger writes
As a result, cities have to "rebalance" bikes by, well, truck. Someone must come along periodically and rearrange the supply to meet the shifting demand. This is a significant expense for bikeshare systems (not to mention an asterisk against their reputation for low-carbon transportation).
But rebalancing is not that big an asterisk. Capital Bikeshare in 2011-2012 had 3 Sprinter vans and some SUVs, which for Cabi's 2nd year [September 2011-September 2012] wracked up just above 320mi/day for rebalancing vehicles, or around 117,000 miles for the year (thanks to Josh Moskowitz for running the numbers for me, which I have been sitting on for nearly two years now). In addition they drove their tech vehicles about 30,000 miles for the year. The Sprinters get about 16 mpg (and the other vehicles probably better mileage) which means that CaBi burned about 9,187 gallons of gasoline in year two.
According to the EPA calculator, that's the equivalent amount of CO2 (81.2 metric tons) produced by 17.2 average passenger cars in a year. Meanwhile, CaBi reduced driving enough to cut 3.7 million pounds of CO2 (1678 metric tons). Meaning that the rebalancing only gives back about 5% of the savings.
Still, we could do better.
Alternative fuel and even human-powered redistribution vehicles are deployed elsewhere, and especially if operations are used to substitute for additional capacity, it is important that CaBi ensure that it minimize its environmental impact....CaBi should purchase and operate a varied fleet of redistribution vehicles, with the goal of deploying the lowest impact vehicle necessary to adequately service a particular node of the system