I rode my bike to work for about a month when I first moved close to my job (~1.5 miles). I eventually got tired of it. I'd be hot & sweaty to start my day (this was the month of June), and it would take me a while to cool down. This sucked in an office environment, when I'm always wearing button-ups/polos and slacks. I'd also have re-do the hair when I got in due to helmet head.

But the biggest reason I stopped was traffic. Downtown Denver is not a bike friendly place, unlike Boulder where I'd lived before. There are no bike lanes, and the sidewalks are narrow, disjointed, and cluttered with people. People also drive really fast out of alleys without checking the sidewalks (I almost got demolished by a garbage truck). So after a couple of days on the sidewalks I took to the streets. The lack of bike lanes means I have to ride with the traffic, and drivers aren't respectful of your space AT ALL. I almost got my handlebars clipped several times.

So even though I'm only 1.5 miles from the office I drive or ride the motorcycle in everyday. Too many negatives to riding the bike.