I live 1.1 mile from my work, so the trip is quick, the road is flat so not a problem.
I even bike during the winter. Last winter we had six weeks of snow on the ground (Rare in Western Pennsylvania, our normal winter is 1-3 days of snow than 1-3 days of above Freezing temperatures and the snow melts, than it snows again. This freeze=thaw cycle starts in early December and ends about Groundhog's day (We get snow before and after but rare and rarely lasts more than a day or two). Now out heavy snowfalls tend to be in October, November or March. These can leave feet of snow, but is generally gone within two days and nothing again till after Thanksgiving.
Given this situation I use by summer tires on my bike as long as I can (Most years that is all year round). The last two winters I have had to use some studded tires on my bike do to the ice. I still maneged to bike to work but the studded tires roll Resistance was very noticeable. As soon as the weather broke (i.e. above 32 Degrees for more than two days) I switched back to my summer tires and have been using them ever since.
I wish I could say I have no car, but that would be a lie, I own and use a Jeep Wrangler. I drive it about 1-2 times per week. I have to go to my county seat 1-2 times a week and it is 23 miles away - All up hill (I know I have biked it at least once every year since 2000).
Know I could bike to my County Seat, but the quickest way is on a busy two lane road. Th edge of each lane and the road end at the same spot i.e. NO break down lane, no sidewalk, no place other than the lane to ride a bike. Furthermore it is all up hill, Johnstown elevation is
Johnstown is 1184 feet above mean sea level, the County Seat is Ebensburg and its elevation is 2140, thus I must climb 944 feet (and this is NOT a constant climb, it is up and down, through the single biggest climb is almost 90% of the 944 Feet).
As I told someone, three hours to the county Seat, two hours back (Last year, 2003, I went a different way along a not yet finished bike trail and it was 4 hours there and 3 hours back, the difficulty of the trail slowed me down). Hopefully the trail be finished this year so I can see if I can get to Ebensburg in three hours along the trail and New Germany Road, which is the same time it takes me if I take "Old 219".
For elevation of a city of Town see:
http://www.mit.edu/geo?location=Rockville