Monday, April 21, 2008

Too late for Beacon Street?

There is a solution for the problem created when the city did trial striping of 11-foot travel lanes on Beacon Street between Newton Centre and Hammond Street: asymmetry.

But, first, a recap of the problem. While it's just a two-lane road (with some exceptions for turning lanes at the intersections), Beacon Street is wide, really wide. Striping 11-foot travel lanes leaves, at various places, shoulders as wide as or wider than the travel lanes. What initially seemed like a great boon to cyclists turns out to be a problem. The shoulders are so wide that motorists confuse them for travel lanes.

Because parking is legal along much of that stretch of Beacon, you can't just use up the shoulders with dedicated bike lanes. The shoulders are wide, but not wide enough for parking and a four- or five-foot bike lane. The real shame is that the parking is rarely used.

The infrequency of parking along Beacon east of Dalton Street may be the key to a solution: a single bike lane, not two.

For those stretches of Beacon where the road is wider than 37 feet, on one side of the street, stripe one 4-foot bicycle lane and a 7-foot shoulder. With two 11-foot travel lanes, that leaves 4 feet or more for the shoulder on the other side.

Because there are so few cars parked on Beacon, the "other" shoulder will essentially function as a bike lane. (Parked cars in the diagrams are shown for scale only, not to represent parking frequency.) And, a smaller shoulder won't create the very dangerous situation that exists now with cars traveling in the shoulder as if it's a travel lane.

Where the road is wider than 41-feet or so, leave the other shouder at 7-feet and expand the shoulder next to the bike lane. There's less likelihood that the next-to-the-bike-lane shoulder will be confused with another travel lane.

Needless to say, there are other parts of the puzzle. You'd have to figure out the intersections, for one. But, this addresses the main problem.

So, why the headline? Because the city has rendered the temporary, dangerous striping scheme, which was painted, in thermoplastic ... apparently in the last few days. This despite criticism of the scheme from the Newton Bicycle Pedestrian Task Force, aldermen, private citizens, and NS&S and recognition by various DPW officials that the scheme was imperfect.

Note: Between Langley and Dalton Street, Beacon Street is probably wide enough for parking and bike lanes on both sides.


Charlie D. said...

I love the idea of bike lanes on Beacon St. One thing to note is that a bike lane next to parallel parking should really be at least 5 ft wide. 4 ft is generally only used when no parallel parking is present.

To get 5 ft bike lanes, you could use 10 ft travel lanes. This has been done in Cambridge along Hampshire St, and a study shows that it works quite well. The dimensions there are 10 ft travel lane, 5 ft bike lane, 7 ft parking. That's pretty much the smallest you'd want to go for lane widths, but it works. So in total, bike lanes with parallel parking on each side can work on a 44 ft roadway.

Any chance on Beacon St of getting parking banned from one side? If the demand is low, perhaps it's not needed at all. Then, in the 37 ft sections you could do 5, 10, 10, 5, 7. And in the 41 ft sections you could do 5, 11, 11, 5, 9.

Steve Runge said...

I'm also a fan of one-sided parking. It doesn't make sense to me to allow parking on both sides of an artery when parking is used only occasionally.

As to the extra-wide shoulder lanes, I watched two cars using one for travel yesterday. (eastbound Beacon, between Glen Ave. & Hammond Pond Pkwy) I think the fact that they straddled the line somewhat suggested they didn't know quite what to do.