I live in a rural area and in the summer, I take a 6 km. shortcut to work on my bike (partially off-road). It takes between 15 and 20 minutes, but I don't push it; I don't want to be too sweaty when I get to work. The season lasts about 5 1/2 months; otherwise, it's raining, too cold or narrow, snow-covered roads or roads with snow banks on each side, making it unsafe to share the road with cars.
It's usually night when I return home and I use an Elektro Lumens ElektroStar 1 Watt Luxeon headlamp clamped to my bike's handlebars as a headlight -- I run it on 4 rechargeable NiMH AA cells. Very functional since it's a rural area with little or no electrical lighting for most of the route.
In the winter, I have to take a longer route, about 9 km. on three different country roads, with 1 stoplight. Takes about 10 - 15 minutes depending on traffic and weather. I drive a somewhat cranky 1996 Plymouth Voyager van.
Other choices include walking (cold, slow and impractical in winter) or taxi (too expensive). Public transportation covers only one segment of the route.