Response to Adam Auster’s comment about Arlington Center

I’m responding to Adam Auster’s comment on my previous post:

On the other hand the route would cross the sidewalk, which can be quite busy, 3 times. (To say nothing of the crosswalk because you already mention it.)

Let’s compare the actual conflicts:

Eastbound traffic, in the town’s plan:

(I also discussed this in my previous message.)

Eastbound cyclists headed from the path mix with sidewalk traffic on the northwest corner of Massachusetts Avenue and Mystic Street. There are 16 different movements on the corner: from each of the five entrances: the path, the two sidewalk directions and the two crosswalk directions to each of the other four. Only two of those movements are unlikely: those between the path and the Mystic Street sidewalk, which both go in nearly the same direction. In addition, this corner is where crowds wait to cross the street. This is a very complicated and confusing situation, where bicyclists, pedestrians and vehicles in the street are concealed by one another.

The eastbound cyclists then cross Massachusetts Avenue on a protected signal phase (though with some risk from illegal right turns from Mystic Street) and are directed to wait in a two-way left-turn area in the middle of the busy intersection until the traffic signal changes. Cyclists are protected by traffic-signal timing as long as they leave the two-way left-turn area promptly, and this is not obvious. The two-way left-turn area is too small to accommodate the likely volume of traffic.

The cyclists are expected to continue from eastwards in the bike lane on the south side of Massachusetts Avenue, which crosses three driveways, and then turn right either at a meandering path before Swan Place, or into Swan Place (It isn’t clear which, from the town’s drawing). From Swan Place, they enter he continuation of the path.

Eastbound bicycle traffic, in my proposal:

Eastbound cyclists turn left to cross across the west-side Mystic Street sidewalk where there are only two conflicting movements: sidewalk traffic in either direction. It isn’t quite clear in the drawing I revised, but I would have cyclists cross on the side of the crosswalk which is away from Massachusetts Avenue.

Eastbound cyclists then cross Mystic Street on the same signal phase as pedestrians. This crossing from west to east is the most troublesome for me, because of the potential for motorists turning right from Mystic Street not to yield to the cyclists. On the other hand, the crossing is signal-protected with a no turn on red sign and/or separate right-turn signal. For this reason and because of the width of the crosswalk and path, a right-turning motorist will be looking for sidewalk and path traffic rather than looking left for Massachusetts Avenue traffic. Most bicyclist left-to-right in crosswalk collisions occur where the motorist is looking left for traffic.

The other likely potential conflict here is with right-turning traffic from Massachusetts Avenue, but here, bicyclists are in full view of the motorists and the bikeway is far enough from the corner that motorists have time to yield.

Eastbound cyclists then cross the sidewalk on the far side of Mystic Street, but again where there are only two movements with which they must negotiate: sidewalk traffic in either direction on Mystic Street.

Bicycle traffic and sidewalk traffic cross over each other in front of Whittemore Park, as shown in the drawing, but again there are only two conflicting movements with which bicyclists must contend. One hardly even counts as a conflicting movement, as the bicyclists are traveling in the same direction as the pedestrians and pass them either on the left or on the right, depending on timing.

Cyclists then cross Massachusetts at the signal-protected crossing to Swan Place. There are no potential conflicts except with bicycle and motor traffic turning left from Swan Place onto Massachusetts Avenue. Cyclists continue on Swan Place, turning left into the continuation of the path. There is a potential conflict with oncoming traffic, as with any left turn on a two-way roadway, but this traffic is very light.

Westbound bicycle traffic, in the town’s plan:

(I also discussed this in my previous post.)

Cyclists turn right from the path onto Swan Place and jog to the right into a bike lane, creating potential confusion for motorists who think the cyclists are turning right onto Massachusetts Avenue. . They then cross at the newly signalized intersection and turn sharply left into a bike lane.
The bike lane is hidden behind vehicles waiting to turn right, until it bears right to be on the right side of the right-turn lane.
Cyclists turning the corner are is in theory protected by a no turn on red signal and separate signal phase, but as noted by several commenters at the public hearing, right turns on red still occur. There is a risk of right-hook collisions and long-vehicle off-tracking crashes.
The bike lane jogs over to the right around the corner, and then cyclists swerve left into a bike lane. Again there is the risk of confusion because the bicyclists appear to be going straight, however, they are on a protected signal phase.
Bicyclists cross in the bike lane or “crossbike” and then must beat their way through the crowd of people waiting on the corner, making one of the 16 possible movements here.

Westbound bicycle traffic, in my proposal:

Cyclists turn right from the path onto Swan Place and continue to Massachusetts Avenue. They then cross at the newly signalized intersection and turn left to continue past Whittemore Park.
The first potential conflict cyclists encounter is with pedestrian traffic on the sidewalk. They are crossing from left to right, so they must yield to oncoming pedestrians and merge either in front of or behind pedestrians traveling in the same direction.
Cyclists then cross the Mystic Street sidewalk, with only two conflicting movements, same as for westbound cyclists.
At Mystic Street, the cyclists cross on a protected signal phase along with pedestrians. There is risk of collision with motorists who turn right, both at the start and end of the crosswalk, but again, these motorists would be turning right on red illegally, and the bikeway is away from the corner, reducing the risks in the same way as described for eastbound cyclists.
Cyclists then cross the Mystic Street sidewalk, where there are two conflicts, and cross the very unlikely conflict with traffic turning sharply left onto the Mystic Street sidewalk from the extension of the path.
Pedestrians are expected to take entirely different routes using the sidewalks. I predict that many cyclists will continue to use the sidewalks.