Are we talking about the United states or Europe?
Europe "especially Denmark" have addressed the car/bike situation.
My home city Varna has a giant park running along it and major boulevards with restaurants and stores have always been bikes and pedestrians only.
If you follow my comments I said if there are separate exclusive bike roads it makes sense. Biking with cars is where it gets really stupid and arguing that riding a bike in "lets say NY City" is healthy is ether ignorant or some serious propaganda.
Lets make an experiment:
You come inside my garage next to my car, we close it and start the engine. Lets see who dies first.
Even if taking air from outside cars have good filters. My car has Hepa filters. A lot better then biking behind a bus while your lungs are physically open.
Now this graph bellow has to be explained with simple math:
Your lungs work 5 times more when exercising.
You breathe 15 times a minute normal state - "12 liters of air" and 40-60 times a minute "100 liters of air" when exercising.
The 11m biking from the graph above become the equivalent 56-60 minutes of pollution and actually even worst than walking.
SO BIKING IS THE MOST UNHEALTHY WAY OF TRANSPORTATION.
This seams like another one of those dumb studies made to engage the upper class and propagandize a certain political agenda.
From Your lungs and exercise (nih.gov)
"During exercise, two of the important organs of the body come into action: the heart and the lungs. The lungs bring oxygen into the body, to provide energy, and remove carbon dioxide, the waste product created when you produce energy. The heart pumps the oxygen to the muscles that are doing the exercise.
When you exercise and your muscles work harder, your body uses more oxygen and produces more carbon dioxide. To cope with this extra demand, your breathing has to increase from about 15 times a minute (12 litres of air) when you are resting, up to about 40–60 times a minute (100 litres of air) during exercise. Your circulation also speeds up to take the oxygen to the muscles so that they can keep moving."