(Ben Claassen III/For Express)

The world is made up of two types of people. Determining which kind you are doesn’t require a whole BuzzFeed quiz. Just answer one question: What do you think about a road that terminates in front of a cluster of homes?

Some folks would consider that a “cul-de-sac,” a French phrase that evokes images of tykes frolicking on manicured front lawns. To the rest of us, it’s the phrase’s English translation (“bottom of the bag”) that seems like a more apt way to describe a spot that’s been cut off from the rest of a community.

Ben Ross taps another synonym for the title of his new book, “Dead End: Suburban Sprawl and the Rebirth of American Urbanism” ($30, Oxford University Press). Although it’s ostensibly the story of where we live, the message is focused on how we move — which makes sense considering that Ross was president of Maryland’s Action Committee for Transit for 15 years.

The longtime Montgomery County, Md., resident, who’s a hydrogeologist by trade, got involved in transit advocacy to support the Purple Line. A light rail route that would connect Bethesda, Silver Spring and New Carrollton seemed like a “dream” to him. It would ferry passengers between busy job centers and spur walkable development throughout the county. So why has the proposal been so controversial?

“It’s a clash of value systems,” says Ross, 65, who’s learned that his opponents have one main concern: change. “They believe single-family houses and automobiles are superior to everything else,” he says.

Those beliefs created the problems that now need to be addressed, Ross says. He points to the high-profile local examples of White Flint in Maryland and Tysons Corner, Va., which are being transformed into places where people will be able to get around without a car. He’s more optimistic about White Flint’s plan, with its larger network of connected small streets. It’s areas that have a true grid — without too many of those rascally dead ends — that are most conducive to walking, he notes.

But the amenity that can really make or break a place, Ross says, is train service. Buses are an important part of a transportation network, but unless they have dedicated lanes, they’re still “hitting the same potholes as every car around them,” Ross says. “The train is what makes it advantageous not to drive. It’s what brings all income levels together. It’s what puts people on the streets in large numbers.”

That’s why the Purple Line — now slated to open in 2020 — will make the D.C. area a nicer place to be. And that’ll be true, Ross says, no matter what kind of person you are.

Details: Ben Ross will give a free talk at 5:30 p.m. Tuesday at the American Public Transportation Association (1666 K St. NW, #1100). At noon May 12, he’ll speak at the National Building Museum (401 F St. NW). It’s free, but preregistration is required at nbm.org.