Great news. Could means that drivers are using bikes instead of cars. Though this study doesn't say that since there is other means of transportation other than driving, riding a bike and walking.
A french study from ORS ile de france said that the biggest reduction of pollution that cyclists could have is when drivers switch to bicycles or public transportation rather than when people using other means of transportation than cars switch to bicycles or public transportation.
Though car pollution is nothing when compared to ships pollution as 16 big ships pollute as much as all the cars in the world.
How 16 ships create as much pollution as all the cars in the world | Mail Online