Quantifying greenhouse gas emissions reduction from bike share systems: a model considering real-world trips and transportation mode choice patterns

•Annual emission reductions of the eight bike share systems range from 41 to 5417 tons CO2-eq.•Bike share systems can only reduce less than 0.1% of GHG emissions from the transportation sector.•Bike share stations in the city center reduced more GHG emissions overall.•Bike share stations away from the city center reduced more GHG emissions per trip.