A study at Portland State University explores the potential for economic impact upon businesses, when automobile accommodations are lost to bicycle infrastructure. Preliminary results reviewed in the Bike Portland blog imply quite the contrary. While motorists averaged more dollars spent per trip, they made fewer trips. Thus, customers who arrived by car spent the lowest amount per person per month, when compared with those who bicycled, walked, or came by public transit. The article may be found
here. Ongoing study is scheduled to continue through September.