Each year, the U.S. Census releases an update in “commuting mode shares” in its American Community Survey. This is an annual accounting of the share of people in every U.S. city who bike, walk, or ride public transit to their jobs, as well as drive. Mostly the latter: Nationally, about 75 percent of the country is sitting alone in their cars every morning. About 10 percent carpool, 5 percent ride transit, and the last 10 percent either walk, bike, or work from home.
If you peruse this data-dump every year, you’ll probably notice something: Despite the tireless efforts of transit planners, bike-lane boosters, and other actors in the mobility arena, the mode-share percentages don’t seem to budge much in the any given growing city as they add more people, despite massive investments in transit infrastructure. Take Dallas, Texas, for example: In 1996, that city opened the first stage of its light-rail network, which has since grown into the largest system in the U.S., at a total cost of something around $5 billion. But the share of commuters in the city who ride transit has remained below 6 percent since 1990.