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Starts & Stops

Markings give priority to bicyclists

Brighton Avenue in Allston features “sharrows” with extra lane markings, an idea the city is testing.

Martine Powers/Globe Staff

Brighton Avenue in Allston features “sharrows” with extra lane markings, an idea the city is testing.

A new set of street markings on Allston’s Brighton Avenue isn’t simply an errant set of dashes installed by city staff with extra paint — it’s part of a national experiment to test innovative bike facilities.

I first noticed the markings last week while driving through Allston Village. Running down the right-hand lanes on both sides of Brighton Avenue are bicycle-priority icons, known as “sharrows” in cyclist parlance, hugged by two sets of dashed lines along either side that make the lane look more like an airport runway.

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My first thought: Sharrows on steroids!

And Boston bike czar Nicole Freedman said that’s exactly what they are. (Well, except that the former Olympic cyclist wasn’t too happy about the doping analogy.) Officially, the markings have a more dignified name: priority shared-lane markings.

Sharrows, or shared lane markings, indicate that cars must share the lane with cyclists. Transportation officials use them on roads when there’s no space, money, or political will to section off pavement for bike lanes. For that reason, the sharrows are often viewed in bike circles as low-hanging fruit: The wimpiest, least ambitious method of asserting space for people who ride bikes.

But when it came to Brighton Avenue, a road well-traveled by cyclists but too narrow for bike-only lanes. Freedman and her staff brainstormed about finding a way to beef up the garden-variety sharrow.

“We could not remove a lane to put in a bike lane, and we could not remove parking — that’s a fact,” Freedman said. “We said, this is such an important part of the network — can we do better than standard sharrows?”

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The concept of priority shared-lane markings is detailed in a 2009 research paper by Peter Furth , civil engineering professor and bike infrastructure expert at Northeastern University, who first came up with the idea.

The street markings, he wrote, can help provide the “feel” of a bike lane — even if there’s no room for one.

“It is a design option for a ‘just-in-time’ bike lane with the potential to offer bicyclists a level of safety and comfort that approaches that of an exclusive bike lane,” Furth wrote.

The “sharrows on steroids” have little precedent: Only a couple of other cities in the United States have tested them.

Some may view the addition of dashed lines to the sides of sharrow icons an underwhelming innovation. But Freedman said she believes drivers will intuitively see the dashed lines as an indication that they should use the left-hand lane if traffic is free-flowing, leaving a wide berth for cyclists in the right-hand lane.

In coming months, Boston Bikes staff will take a census of how many cyclists use that stretch of road to determine whether the “sharrows on steroids” increase ridership. Next spring, they will paint the area between the dashed lines lime green, and conduct another ridership survey.

Freedman’s office will report their findings to the federal government. And if they’re successful, the idea may get exported to other cities around the country — and to other parts of Boston.

Left turn on red?

With all the brouhaha in the past two weeks on the issue of a right turn on red coming off Massachusetts Turnpike Exit 16 in Newton, another wave of readers wrote to ask about a similar — but much, much more straightforward — issue of left turns on red.

The setup: You’re driving on a one-way road, arrive at an intersection, and hope to turn left onto another one-way road. The light is red. Are you allowed to proceed left after stopping?

Check it out in the most recent version of the Massachusetts Driver’s Manual, page 94 : The answer is, unequivocally, yes, you may turn here — unless there is a “no turn on red” sign.

Phew. That one was easy.

Martine Powers can be reached at martine. powers@globe.com. Follow her on Twitter @martinepowers.

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