One day I was a passenger in a car on the Longfellow Bridge coming into Boston from Cambridge. Bob was driving and Ann was in the front seat. We began discussing the upcoming reconstruction of the bridge and the granite at Charles Circle that bordered a sidewalk.

“How wide is that sidewalk anyway?” asked Ann.

“Let’s find out,” said Bob as he turned the car around into the lane that serves as a driveway for the John Jeffries House.

He pulled out a tape measure, and we hopped out of the car. He and Ann started measuring the sidewalk.

“These are my people,” I said to myself—the kind that would measure a city sidewalk. My people are city nerds.

How can you tell if you’re a city nerd? You don’t necessarily have to go around measuring sidewalks.

You’re a city nerd if you can define FAR, know what an EIR or a PNF is, and what BRA stands for. Look them up if you don’t. If you have actually read an EIR, give yourself extra points for city nerdism.

You’re a city nerd if you have an opinion on whether the BRA should remain as it is, or that its dual functions of planning and approval should be separated. You’re a city nerd even if you can’t convince anyone that the model you’d use to replace the BRA would work any better than the BRA does now.

You know you’re a city nerd if you can tell the difference between running bond and Flemish bond. These terms describe patterns in which bricks are laid.

You know you’re a city nerd if you look forward to public meetings in which developers or institutions present their plans, the attendees accuse them of nefarious motives and hidden agendas and then maintain that the project at hand will destroy life as we know it, and someone always gets mad.

You’re a city nerd if you time walk lights, take pictures of trash bins and traffic lanes in other cities, and have an opinion on the kind of tree the city should plant in the pit in front of your house.

You’re a city nerd if you subscribe to Bob O’Brien’s news feed. You don’t know about Bob O’Brien’s news feed? Bob said it was okay to tell you about it. Contact him at rbobrien@rbobrien.com if you want to get 20 to 40 emails a day containing articles on architecture, city planning, parks and traffic matters that have appeared in every itty bitty journal, newspaper online publication or magazine. You wonder how he has time to read it all. And you don’t have time to read it all. But the topics appeal to city nerds. I’ll admit I read a lot of them, and so do the sidewalk measurers.

Come to think of it, you’re a city nerd if you know Bob O’Brien. He’s the executive director of the Downtown North organization. If you know that Downtown North is the name promoters gave to the Bulfinch Triangle, you’re on your way to becoming a city nerd.

You’re a city nerd if you read all the neighborhood weeklies and subscribe to NorthEndWaterfront.org, which covers a lot of downtown. Knowing Matt Conti, who produces this gem and is a city nerd himself, gives you extra points toward nerdism. He films North End, Waterfront and Downtown neighborhood meetings so if you’ve missed one, you can watch people behaving badly—and sometimes wonderfully—in the privacy of your own home.

You’re a city nerd if you realize that green space is only good in the right places and in some locations a building is better. You’re a city nerd if you know the meaning of “street wall” and if you’ve used Citizen’s Connect. (It’s a smart phone app for reporting problems.)

You’re a city nerd if your first method of transportation is walking, your second is the T and your third is a taxi. Getting in your car, unless it is a Zipcar, is a last resort for city nerds. Many city nerds bike, and the rest are trying out bicycles now that we have Hubway.

If you’re a member of Hubway, it’s a point in your favor for deep city nerdism.

Personally knowing your elected officials and city employees earns you credits in city nerdism. If you’ve been invited and actually gone to the city’s traffic control room at City Hall, you’re an experienced city nerd.

If you’ve visited what is said to be Hanover Street beneath City Hall Plaza, you’ve topped the list on city nerdism. I haven’t done that, and I want to.

If you enjoy process as much as production, you have tendencies toward city nerdism. Sometimes there are people who’d like for the process to go on forever, because it is more interesting than producing something.

Practicing city nerdism is satisfying to those who participate in it. You could be spending your time in less productive ways.