I'm biking down Beacon Street in Somerville toward Inman Square. This stretch of road has no bike lane, so I'm extra wary of turning cars and doors suddenly flinging open. I feel like a guerrilla cyclist.
But when I hit the Cambridge city line, it's like crossing from the dark side of the moon to the light. A bike lane suddenly appears. The street changes its name to Hampshire here, and if I'm continuing onto Kendall Square and over the Longfellow Bridge, I feel protected all the way to Boston.
At the other end of the bridge, the lane disappears as mysteriously as it appears. For that two-mile stretch, however, I let my guard down somewhat and feel more confident cars are aware of my presence.
Gone are the days when cycling advocates bickered about whether bike lanes actually improve safety for cyclists. Studies prove that bike lanes and other markings boost bicycle use, reduce vehicular traffic and speeding, and in many cases, decrease car-bike collisions.
"A handful of people are opposed to bike lanes on a philosophical or practical basis," wrote Chris Porter, chair of the MassBike Metro Boston chapter, in an e-mail. Many of this minority are holdovers from the days when "vehicular bicycling" thinking - folding bikes into the regular flow of traffic with no special accommodations - held sway. MassBike and other major bike advocacy groups support bike lanes, as long as they are designed properly. But bike lanes aren't the only option.
"Not every street is right for a bike lane, but there are plenty of alternatives, like bicycle boulevards, "sharrows" [or] "Share the Road" arrows, and signage," said David Watson, MassBike's executive director.
The city of Cambridge has installed 37 miles of various accommodations, including contra-flow lanes (which let bicyclists travel against the flow of traffic on a one-way street), and edge or guide lines (stripes that designate a space between the travel lane and parked cars).
"If you can ride to keep up with traffic, bike lanes, and [riding in] travel lanes are better," noted Doug Mink, a longtime bike advocate with MassPaths and MassBike. His 20-mile daily commute (12 of them on bike paths) takes him from Roslindale to Cambridge. "If you are slow or traveling with kids, [off-road] paths or cycle tracks are lots better."
Roads often need to go on "diets" to either remove or narrow a lane of traffic or parking to make a little room for bikes. This is what happened on Mass Ave in Central Square, said Cara Seiderman, transportation program manager for Cambridge.
Eleven feet is a generally accepted minimum width for a busy urban travel lane such as on Mass. Ave., said Seiderman. Cambridge has found that even 10-foot lanes, like on Hampshire Street, are as safe as wider lanes. One reason: they slow traffic.
Most engineers design at least five-foot-wide bike lanes, but not every advocate agrees about appropriate widths. Some believe that even standard widths "encourage bikes to ride too close to parked cars," said Porter. In other words, raising the threat of getting "doored."
But a 2003 study by the city of Cambridge found that bike lanes and pavement markings actually encouraged bicyclists to travel further from, not closer to, parked cars, compared with their behavior when no markings were present. Motorists also cited bike lanes as a big reason why they noticed bicyclists.
In short, bike lanes work.
But cyclists can become frustrated when lanes appear haphazardly. "They only exist for a couple blocks at a time and then they disappear entirely," said Allston's Michael Blair, a 55-year-old bike commuter, of local bike lanes. He complained the lanes then "re-exist with no rhyme or reason a couple blocks further along." Blair also cautioned that the white thermoplastic bike lane edge lines themselves can be a hazard. "All it takes is a heavy dew to turn those markings into a Slip 'n Slide."
Vanishing bike lanes can cause confusion. "[Crashes] are more likely to happen at intersections where people are turning, or where a bike-specific facility is beginning or ending, where behavior of bike and cars has to change," said MassBike's Watson. "If it's not carefully designed, people don't know what to do."
Which is why I found myself in Inman Square on a sunny April afternoon, asking bicyclists how they felt about that Somerville-Cambridge transition and if crossing into Cambridge made them feel more secure.
"I do feel safer," said Bill Boos, 33, of Cambridge. "At least it makes cars more aware that this is a designated space."
But without a bike lane, said Christine Wichers, 41, "I'm a little more tuned into the cars around me."
Even with lanes, cyclists mentioned that motorists sometimes ignored them. Vigilance is still essential.
Roads may be on a diet to make room for bikes and pedestrians, but cars are getting obese. Which leaves one solution, Wichers said. "We just have to keep the Hummers off the streets."
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Bike events and news
"Boston Greenways: Eight Missing Links" presentation of Northeastern University professor Peter Furth's civil and environmental engineering students' designs for multi-use paths. April 22, 6:30 pm, 108 Snell Engineering Center, Northeastern University.
Get comfortable riding around the city with MassBike's free two-hour Bicycling Safety Workshop, April 23 in Cambridge. More info: massbike.org/skills/classes.htm.
MassBike Metro Boston chapter Spring Social, 6:30-8:30 p.m., April 30, Cambridge. Contact 617-417-3133 for details.
The Boston Metropolitan Planning Organization seeks volunteers to help count bike trail users on May 3 and 6. Contact Cathy Buckley Lewis at: firstname.lastname@example.org or 617-973-7118.