Almost everyone in the US drives to work
If you live in one of America's major cities, mobility often feels inextricably linked to public transportation. New York City couldn't function without its iconic subway. Washington, D.C., and Los Angeles have made big expansions to their metros. Chicago and San Francisco are planning state-of-the-art rapid bus lines to complement their rail systems. Even historically sprawling, car-reliant cities like Denver, Phoenix, and Houston are betting on light rail to guide their future growth.
Amid news of all this transit growth, it's far too easy to forget that on any given day most city residents still drive to work. The Atlantic Media/Siemens State of the City poll is a sobering reminder of that reality. Among every single urban demographic group—let alone non-urban groups—the majority of respondents commuted by car...
Most people in Europe, by the way, also drive to work.
This is not news, but it's a reality-check for the anti-car bike movement. See page 3 of this ACS report to understand the insignificance of cycling and the importance of motor vehicles for Americans. See Wendell Cox in New Geography for a thorough analysis of this reality.
Why do people drive to work when public transportation is cheaper? Because it's a lot faster, and people can access more jobs in a much wider area with a car. A pro-bike writer concedes that
...people make rational calculations to drive so much of the time, even in cities where decent transit does exist. The total financial cost per trip of driving somewhere is likely higher than taking transit (or biking), once you factor in car payments, insurance, and maintenance. But we tend to treat those as sunk costs. And so we often make travel decisions with a time budget in mind, not a financial one. By that metric, it's clear here why people who can afford to drive often chose to. It's also clear on these maps that people who can't afford a car pay a steep penalty in time to get around (emphasis added).
Not having cars is a serious handicap for the poor, since public transportation can't realistically provide access to a wide area when you're looking for a job.
In San Francisco a much lower percentage of people drive to work, with 36.6% of commuters driving alone, and 46.6% of commuters overall relying on motor vehicles. Only 3.6% of city commuters ride bikes to work, though the city is claiming that the latest ACS numbers make it 3.8%. 33% of city residents take public transportation to work.