Winter (ice, snow, freezing winds)
Rain storms
People who don't want to show up to work sweaty (my work never had showers and I'm the sort of person who creates a lot of sweat (and smell) even if I'm taking it easy on a bike
People who live more than X miles from where they are going
People who live up/down major hills
etc.....
I lived IN Boston for a while, and actually rode my bike to work during the summer (didn't own a car) and just let everyone suffer through my sweat. But I couldn't do it in the winter (yes I know some people do). Aside from the physical cold/misery, the snow and ice made many roads extremely dangerous. The last few places I've lived were in the suburbs, commuting to other suburbs (luckily I've been avoiding the worst city traffic). The distances were too great to bike (unless you like a 3+ hour commute). shrug. Its great if you live somewhere that biking works for you, but don't expect everyone everywhere can just give up their car, jump on a bike, and carry on with life...
There's a difference between "can't" and "don't want to". I'm not going to tell anybody what they should or should not do for their transportation. If you prefer driving, for whatever reason, go for it! I'm not going to say you're wrong.
My main point is that a lot of people assume that biking is the worse choice for them without actually knowing.
I have noticed that most people I know who have tried bicycle commuting and gave it up didn't really give it a fair shake. They used substandard or the wrong type of bikes, didn't use the accessories and clothing that make it feasible (rain gear, panniers, trailers, etc), and so forth. They just grabbed their old bike out of their garage and hopped on. That can work, but it's not usually the best experience.
Wow, excuses? Ok. Yes, car driving is easier, it always will be. But how about you drivers start actually paying for what you use, the pollution you create, the roads that are paid for by taxes?
No, since that only covers a small amount of what you use. Think about the 40,000 deaths a year. Who pays for that? Not you. The 500,000 seriously injured? Not you. The pollution you cause? Not you. The 3m children with Asthma caused by drivers? Not you. The list goes on...
I lived IN Boston for a while, and actually rode my bike to work during the summer (didn't own a car) and just let everyone suffer through my sweat. But I couldn't do it in the winter (yes I know some people do). Aside from the physical cold/misery, the snow and ice made many roads extremely dangerous. The last few places I've lived were in the suburbs, commuting to other suburbs (luckily I've been avoiding the worst city traffic). The distances were too great to bike (unless you like a 3+ hour commute). shrug. Its great if you live somewhere that biking works for you, but don't expect everyone everywhere can just give up their car, jump on a bike, and carry on with life...