As a rule of thumb, people travel 4-5x as fast on a bike as on foot. (Hills, ice, etc. complicate this, of course.) Bikes are probably best suited to trips of

As a rule of thumb, people travel 4-5x as fast on a bike as on foot. (Hills, ice, etc. complicate this, of course.) Bikes are probably best suited to trips of about 1/4 - 10 miles, alone, with less than fifty pounds of cargo. (That covers more trips than many people realize.) Riding a bike three blocks is probably not worth the trouble, and riding fifty miles is (while quite possible) going to take a few hours.