To be honest I don't know how they do some of these studies. Or how they justify the conclusions they come to. If people were all that happy cycling to work "I" would have thought more would cycle to work. Nationally we see numbers in the 1 percent to 1.6 percent range. (some cities are higher but don't effect national average) They will tout massive increases but that is what got them to 1.6 percent. Then again if you ask a cyclist how they feel about cycling wouldn't they say it made them happy? Yet having a choice it seems as if cycling doesn't make them happy enough to actually cycle to work. When I see studies like this I take them with a grain of salt. I saw a survey of what car made people the Happiest and Porsche came out on top. But when given the choice by far the most popular vehicle was the Ford F-150. Maybe they ask the wrong people or the wrong questions? I have friends that are happy when they can make a 5000 foot climb of 15 miles in an hour by bicycle. My best time is closer to two hours. But while they are happy getting there I am much happier on the way home. They need a study to see if climbers or a descender is happier so I will know.