Traffic Studies

Monday, November 17, 2008



Rick Bryant, vice president for planning at Tetra Tech Rizzo, explained it all to us recently at a Real Estate Finance Association "Fundamentals of Real Estate" program at the offices of the law firm Wilmer Hale.

In "Inside the Traffic Study: Pivot Point for Every Development," Bryant made one of those essential points that we all know is true but find hard to adhere to. That is, the more time and money you spend planning, the less the margin of error when the project gets going.

It's sort of an elaboration on the old Boy Scouts motto: Be Prepared. If the Big Dig had been planned longer and better, and not designed as it was being built (sometimes after?), it might not have risen to a cost of $15 billion. But that's cars through the tunnel.

Traffic studies may be required for various stages of the entitlement process for a project: site-plan approval, special permits locally, zoning changes, MEPA certificates, Massachusetts highway access permits, or interstate highway access allowances.

It pays to know what the facts are, in part because what the neighbors think matters. "MEPA tends to side with the little guy ... those who are impacted by a development," Bryant said.

On Cape Cod, the requirement used to be that a traffic study was needed if 25 new car trips were going to be added to the streets. Now it's any new cars.

So, as Bryant says: "I count cars for a living."

Actually Tetra Tech Rizzo does the engineering; it usually hires a specialist traffic-counting firm to actually do the counts, which can be done with hoses across the lanes, or manually by humans.

After studying patterns and determining what is a representative day and time, "We usually only count once," he said.

For the newly proposed mixed-use development at Bayside, in Dorchester, being planned by Corcoran-Jennison, Tetra Tech studied 16 intersections.

That's called the study area, and engineers look at existing conditions, future conditions, and mitigation -- with the goal of bringing traffic service levels back to where they were before the development was added.

"The goal here is to get the 'build' to look like the 'no build', so you have no impact," Bryant said.

That's where the A through F comes in.

For intersections with signals, an A level of service is one where drivers have a delay of 10 seconds or less. A B level is up to 20 seconds, a C level up to 35 seconds, a D level is up to 55 seconds, an E level is up to 80 seconds -- and an F level of service is one where you grind your teeth for more than 80 seconds before the light changes and you get to go.

You know, like that one on Columbia Road at Glendale Street in Dorchester, where five streets come together.

Now, these levels are averages, which is not to say no one ever sat longer than 10 seconds at an A intersection.

It's different for intersections without signals. For those, an A is, similarly, up to a 10-second delay. But for a B level at an unsignalized intersection the average wait can only be up to 15 seconds, C up to 25 seconds, D up to 35 seconds, E up to 50 seconds, and F greater than 50.

So, you have to be more patient at signals than at intersections on streets without them.

A computer model takes the count data and figures out the delays, with an assumption of two seconds between cars.

Left-turn lanes are monitored, but not right-turning vehicles, because delays are longer with oncoming traffic.

"People are very skeptical" of traffic-study findings, Bryant said. Something about the look on his face told us that was an understatement.

They say, "It takes them 10 minutes to get our of their driveway," Bryant said. It may seem that way, but, "You know it never takes them more than 30 seconds."

A neighbor of one project Tetra Tech Rizzo worked on had her daughter do a traffic count to try to prove the professionals wrong.

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Traffic is complicated.

Take Kosciuscko Circle, a rotary at Morrissey Boulevard and Columbia Road that we know well from years at The Boston Globe. It's also near Bayside. We'd have guessed the circle had a very low level of service, crammed and jammed as it is at rush hours, especially evening.

But no.

"It's better than it seemed," said Bryant. It's the oversubscribed on-ramp nearby from Columbia to the Expressway north that messes everything up -- including backing up traffic to and into the circle.

Since the perception of the circle was that it was low, Tetra Tech rated it low in the study.

The state tracks the number of accidents per million vehicles and watches which ones need to be fixed.

On Cape Cod the standard is: If there are five accidents a year, something has to be done.

A "trip generation handbook" helps engineers project new levels of traffic. In general, an office building causes one trip per employee. Retail doesn't -- people double-up more.

Urban buildings, where there is public transit, generally generate less. "In urban life, it's not a Kansas cornfield," Bryant said. "People are going to take the bus."

As for those letters, "We try to get the E's and F's to go away," he said. Sometimes, when traffic can't be improved, off-site mitigation to the community is the answer.





A Corner of Seaport Square

At last week's Boston Redevelopment Authority board meeting, Seaport Square's first building won approval.

Designed by David Hacin, it's a residential building on a parking lot known as Parcel A, and it's one of 20 blocks that make up Seaport Square, a 23-acre development site formerly owned by Frank McCourt, who's now out turning the Los Angeles Dodgers into a good baseball team.

The six-floor building is on a lot that looks like it is part of the Barking Crab restaurant. It will include 34 units occupying 54,400 square feet, including ground- floor retail.

The project was well-received recently by the Boston Civic Design Commission (Hacin, a member, of course recused himself) and will include one-, two-, and three-bedroom units.

The BRA said it provide the missing link between two existing Harborwalk segments.

There had been talk of incorporating the Barking Crab into Seaport Square, but that turned into a big messy misunderstanding. (By the way, the Crab is a great place in winter too, very cozy when they get that wood stove cranked up.)

The new building will cost about $40 million, but credit will have to loosen somewhat before that or anything else new gets under way. Boston Residential Group is working on the residential space in the first building.

Seaport Square is a joint venture of Gale International and Morgan Stanley, with WS Development Associates of Newton handling the extensive retail space.

If the Crab ever does moves, the city will probably get a new little park along the water between the newish Moakley Bridge and the old Northern Avenue Bridge.

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Work was going on at the old bridge recently, by the way, on the underside, where the controls reside that are used to move a section for vessels to pass.

Mayor Menino last week unveiled a plan to raise the bridge and renovate the rusty thing, using its three lanes respectively for shops, pedestrians, and emergency vehicles.

There was a public hearing on the plan last Friday night.






Work was under way recently on the controls on the underside of the old Northern Avenue Bridge, which has to continue to allow vessels to pass until it is permanently elevated. It is also badly in need of painting.

It didn't seem to get much notice, but the bridge was extensively, creatively, colorfully, and lovingly lit up by Fort Point Channel area artists recently. Artists who had to be pretty clever electricians at that.