When people ask me how long the MARC train ride from Baltimore to Washington takes, I say an hour. But that’s only if I time it right. Let’s say I just miss the 8:10 a.m. train — maybe because my heartless neighbor ignores my request to “Hold the elevator!!” The next one leaves at 9:05 a.m., meaning my trip actually takes closer to two hours.

I’ve always just chalked up those extra-long commutes to bad luck, but to Jarrett Walker, a popular blogger who’s been designing public transportation systems around the world for more than 20 years, they’re proof of the significance of frequency.

“Frequency is freedom,” says Walker, author of the new book “Human Transit: How Clearer Thinking About Public Transit Can Enrich Our Communities and Our Lives” ($35, Island Press). The more often the train/bus/streetcar arrives, the less you need to be obsessed with timetables. That, in turn, allows you to take trips spontaneously — just like people who rely on cars.

So when it comes to thinking about public transit, a lot of what’s on Walker’s mind relates to frequency and how to improve it.

One way to get buses moving faster is to cut down on the number of stops. American transit systems tend to place stops really close together to limit the amount of walking necessary, Walker explains. But that also slows buses down to the speed of molasses. Get rid of some stops, and people will walk more (which they should be doing anyway for their health) and wind up with better, more frequent service.

Sounds like a win-win situation, right? Not exactly. “People who like the bus stop in front of their house will scream,” Walker promises. But to make a transit system that works well for everybody requires individual sacrifices. This brings us to another one of Walker’s ways to improve frequency: more connections.

It’s simply not possible to create routes that will take all of us exactly where we want to go and when we want to go. Much more doable is establishing a grid of reliable transit that requires a transfer if you decide to deviate from a straight path.

If you don’t like transfers, Walker says, that’s just because the ones you’ve experienced have been bad. The way he sees it, all connections should be short, pleasant and — attention, WMATA! — free. “The connection is a necessary inconvenience. It isn’t an added feature,” he says.

For transit systems separated from street traffic, such as our Metro, the future of frequency is particularly bright, Walker predicts. A huge hurdle to increasing service is staffing costs. But if we follow in the footsteps of Vancouver, B.C.’s SkyTrain, a fully automated system, we won’t need drivers any more.

What we’ll always need, however, is clearer thinking about transit — so I don’t have to wait an hour for the next train to work.

Walker’s Paradise

If you want to make a connection with Jarrett Walker, it’ll be easy next week. The author has four stops in the area — all at transit-accessible locations, of course. His local tour starts at noon on Tuesday in Baltimore. He’ll be in Silver Spring that night for a public lecture. On Thursday, he’s speaking at both the National Building Museum and the American Public Transportation Association. For details on how to RSVP for the events (and to learn how to get a $14 discount on the book), visit his blog, Humantransit.org.