The temperature outside is 9 degrees. I drove my roommates car into the store bright and early this morning and saw what we *don't sell* here at the store.
First of all, I got COLD. Why? Because cars have windshields that get frosty and you have to remove the frost before you can safely go anywhere. I wasn't moving around, so I got cold.
Secondly, I got stuck in traffic. Light after light, I moved so slowly. I literally could have jogged into work faster.
And lastly, I burned a bunch of gas.
So bikes... you step outside and go, not giving the cold a good chance to catch you standing around. Dressing appropriately, making sure you are ready to roll and not letting wind be your enemy. Secondly, not riding on main streets while cycling is faster than waiting in traffic on "fast streets". And bikes, unless you are doing something weird, don't burn up the petrol.