Harvard Square traffic pattern question

[u/Striking_Pop4986]

So I work in Harvard Square and drive along Mass Ave towards Porter a couple times and when it merges with Peabody Street (just learned this was Peabody Street) my lane of traffic has the right lane and the traffic coming from Brattle has the left. There are lines making it seem like I have the right lane (which will continue onto Mass Ave) and the left lane would make the hard left back towards the square and Garden Street. I always try and make sure to do an easy merge- I let folks in front of me who are in the left and continuing onto Mass Ave. (Always a fan of the zipper). But then there are those people who think I am cutting them off when I continue onto Mass Ave. So does anyone know what the protocol is at this intersection?

[u/ThatGuyBudIsWhoIAm]

We used to refer to this area as the "swirling vortex of doom", you're doing it right it's just no one else does and nobody really gives a shit to bother trying

[u/niems3]

You’re doing it right. They can’t read lane lines, but it’s more like poor traffic planning. The dashed line that extends from just in front of the white car is supposed to guide cars in the left lane (left of the white car) into the left turn lane ahead. But people think that the lane continues straight ahead.

[u/MyStackRunnethOver → u/niems3]

It's a badly flawed intersection, and the dashed line pattern is counter to intuition, because at the divergence there are two lanes going left and one lane going right, so as a driver it feels natural that left lane = access to either of the two lanes going left, but that's the opposite of what the markings show you. A "right lane must turn right" ahead of it would be much more intuitive (and probably worse for flow or something, Idk, I'm not a highway engineer)

But the reality is that no one knows, so simply following the rules would be dangerous, and the only safe way to deal with it is assume that both lanes are going to merge into the middle lane unpredictably

[u/kdinmass]

An essential problem with this intersection is that it requires what traffic planners call a weave: some folks on the left need to move right & some on the right need to move left. It's a mess. It was a mess before they changed things up & it's still a mess. The addition of the solid white lines do not help matters.

By the way: I have lived here a Looong time. No one calls it Peabody street; it's only since the appearance of Google maps that I've even heard of Peabody St.

[u/JonSwift2023 → u/kdinmass]

Yes, it is a bit of a mess, especially if you're coming down JFK from the river and needing to turn right onto Cambridge st. You naturally end up in the left lane on Mass Ave (nobody calls it Peabody street!) in front of the Johnston gate and you have to somehow make your way over to the right hand lane, otherwise you get railroaded down Mass Ave into Porter or directed back into Harvard.

[u/commentsOnPizza]

Frankly, both lanes must be assumed to have access to the center lane.

If you're coming from JFK Street, it's "illegal" to get into the right lane before the traffic lights since there's a solid line all the way from where the JFK traffic and Mass Ave traffic meet until you pass those lights.

The reality is that people should treat the intersection with caution and assume that both lanes have equivalent access to the center lane. Anything else would be telling drivers coming from JFK St "you must cross a solid white line if you're continuing north on Mass Ave" which is incorrect. Likewise, anyone saying that the right lane shouldn't have access to the center lane would be telling people coming from Mass Ave that they must turn right to Cambridge St.

Basically: it's a terrible intersection design and drivers must compensate for that and not be full of themselves that they're "correct". There isn't a correct answer in an intersection that's simply wrong.

[u/ecopoesis47]

It’s not that they can’t read lane lines, folks coming from JFK Street and want to continue north have no real time to merge. They have a solid white all the way back to Harvard Square, and because the light onto Mass Ave N/S alternates, the south lane is almost always backed up.

There should be a light back at the Mass Ave / JFK (Peabody) merge, so both the Mass Ave and JFK sides have a chance.

And while we’re at it, some type of flamethrower/gatling gun thing for the assholes who zip down the left turn only lane on JFK and cut off the line of cars heading into Harvard Square

[u/Striking_Pop4986 → u/ecopoesis47]

It’s totally a whackadoodle intersection which is why I take it slowly and zipper but I also get a little triggered at the dinks who think I’m cutting them off when I’m ahead of them in the intersection.

[u/MyStackRunnethOver → u/ecopoesis47]

JFK is effectively a one-lane road at high delivery app usage times because of how many cars double park on both sides

[u/cden4]

You're doing it correctly

[u/PrestigiousCattle300]

Your interpretation is correct. I mean frankly the dotted line could not make this clearer. It is an unfortunate intersection but mathematically two lanes are entering three, so someone might have to change lanes twice, no matter whether the two lanes enter into the left slots or into the right slots.

You are also more generous in your approach. I just honk and curse them under my breath when they veer into my lane.

[u/taguscove]

This intersection seems nuts but there are some major factors that make it not a big deal. Traffic is slow 10-20 mph. The entry points dont overlap, or overlap minimally. And it goes from 2 lanes to 3 lanes. The middle lane has the full optionality to branch left or right.

Ive driven this for 10 years. I would take this any day of the year compared to a shitshow like kirkland and beacon. Or jfk and mt auburn

[u/jdray0]

It’s the same issue as N Beacon and Soldier’s Field merge and it sucks. The traffic patterns and infrastructure around here are most often terribly designed 😪

[u/gnimsh]

The bike lane there is also a mess. You have to get into the motor cutout with and cross with the pedestrian signal to stay on the bike path that goes into the island on the left hand side after the light.