The Bowtie Intersection is finally getting its moment in the sun

[jakeroot]

One change I would make is to add slip lanes for traffic getting onto the parkway. That ensures that people going left don't hit a red light more than once.

Ped/Bike Safety advocates like it this way though.

People walk across this road??

Maybe not a bunch, but some certainly. Not building infrastructure for them isn't sound practice.

As to the slip lanes: they can be designed to better facilitate pedestrian movements. They are not universally hated. In fact, they can actually reduce crossing distances and provide refuge spots, two important features for pedestrian safety. As well, the crossings at the signal itself are usually safer, as there is no right turning traffic to deal with (and left turns can be protected).

[kernals12]

One change I would make is to add slip lanes for traffic getting onto the parkway. That ensures that people going left don't hit a red light more than once.

Ped/Bike Safety advocates like it this way though.

People walk across this road??

Maybe not a bunch, but some certainly. Not building infrastructure for them isn't sound practice.

As to the slip lanes: they can be designed to better facilitate pedestrian movements. They are not universally hated. In fact, they can actually reduce crossing distances and provide refuge spots, two important features for pedestrian safety. As well, the crossings at the signal itself are usually safer, as there is no right turning traffic to deal with (and left turns can be protected).

This intersection will have no left turns as I explained.

[jakeroot]

One change I would make is to add slip lanes for traffic getting onto the parkway. That ensures that people going left don't hit a red light more than once.

Ped/Bike Safety advocates like it this way though.

People walk across this road??

Maybe not a bunch, but some certainly. Not building infrastructure for them isn't sound practice.

As to the slip lanes: they can be designed to better facilitate pedestrian movements. They are not universally hated. In fact, they can actually reduce crossing distances and provide refuge spots, two important features for pedestrian safety. As well, the crossings at the signal itself are usually safer, as there is no right turning traffic to deal with (and left turns can be protected).

This intersection will have no left turns as I explained.

I was speaking more generally (and mostly towards jeffandnicole's comment) about slip lanes and this impression that they may not be compatible with pedestrians and cyclists.

[froggie]

There are many so-called innovative intersections that do the same thing such as the RCUT, the Michigan Left, the Jughandle, and the Continuous Flow Intersection, but those require a massive amount of right-of-way.

The first two intersections you mention do *NOT* require a "massive amount of right-of-way.  In fact, many RCUT applications require less right-of-way than the roundabouts in the bowtie proposal you showed.

Most Michigan Left applications occur with roadways that already have a wide median, so no additional right-of-way needed there either.

As for the bike/ped comments of the latest posts, Strava heat map data suggests that a number of bicyclists do cross 234 at this intersection.

[jeffandnicole]

One change I would make is to add slip lanes for traffic getting onto the parkway. That ensures that people going left don't hit a red light more than once.

Ped/Bike Safety advocates like it this way though.

People walk across this road??

Maybe not a bunch, but some certainly. Not building infrastructure for them isn't sound practice.

As to the slip lanes: they can be designed to better facilitate pedestrian movements. They are not universally hated. In fact, they can actually reduce crossing distances and provide refuge spots, two important features for pedestrian safety. As well, the crossings at the signal itself are usually safer, as there is no right turning traffic to deal with (and left turns can be protected).

This intersection will have no left turns as I explained.

I was speaking more generally (and mostly towards jeffandnicole's comment) about slip lanes and this impression that they may not be compatible with pedestrians and cyclists.

I didn't say they weren't compatible...I'm just saying that ped/buke people tend to want to stop traffic as much as possible, and even slip lanes are looked upon negatively.

[1995hoo]

One change I would make is to add slip lanes for traffic getting onto the parkway. That ensures that people going left don't hit a red light more than once.

Ped/Bike Safety advocates like it this way though.

People walk across this road??

Maybe not a bunch, but some certainly. Not building infrastructure for them isn't sound practice.

As to the slip lanes: they can be designed to better facilitate pedestrian movements. They are not universally hated. In fact, they can actually reduce crossing distances and provide refuge spots, two important features for pedestrian safety. As well, the crossings at the signal itself are usually safer, as there is no right turning traffic to deal with (and left turns can be protected).

This intersection will have no left turns as I explained.

You mean no left turns will technically be permitted. People on Clover Hill are still going to turn left at the light regardless of what the signs say.

[kernals12]

One change I would make is to add slip lanes for traffic getting onto the parkway. That ensures that people going left don't hit a red light more than once.

Ped/Bike Safety advocates like it this way though.

People walk across this road??

Maybe not a bunch, but some certainly. Not building infrastructure for them isn't sound practice.

As to the slip lanes: they can be designed to better facilitate pedestrian movements. They are not universally hated. In fact, they can actually reduce crossing distances and provide refuge spots, two important features for pedestrian safety. As well, the crossings at the signal itself are usually safer, as there is no right turning traffic to deal with (and left turns can be protected).

This intersection will have no left turns as I explained.

You mean no left turns will technically be permitted. People on Clover Hill are still going to turn left at the light regardless of what the signs say.

They can channelize it such that people can't turn left.

[johndoe]

They can channelize it such that people can't turn left.

IMO this is a drawback of MUT / bowtie - if both the major and minor road traffic can go straight, there isn't really a possible way to physically prevent left turns (as far as I know).  That's unlike RCUT / superstreet, where islands force minor road traffic to turn right.

[1995hoo]

VDOT's tweet this afternoon made me think of this thread. Same intersection.

https://twitter.com/VaDOTNOVA/status/1363928216734416903

[NJRoadfan]

Put some jughandles in and be done with it. 

[NE2]

Put some jughandles in and be done with it. 

These are essentially jughandles.
https://www.google.com/maps/@40.4853807,-74.4223007,3a,60.4y,314.88h,79.07t/data=!3m6!1e1!3m4!1sm38QTADzTPvD8hnaX8ltFg!2e0!7i16384!8i8192

[jakeroot]

Put some jughandles in and be done with it. 

These are essentially jughandles.
https://www.google.com/maps/@40.4853807,-74.4223007,3a,60.4y,314.88h,79.07t/data=!3m6!1e1!3m4!1sm38QTADzTPvD8hnaX8ltFg!2e0!7i16384!8i8192

I love that the standard Jersey left is basically just every other states' unofficial impatient left turn. Aka, "this left turn signal fucking blows, I'm going right and banging a uey".

[kernals12]

Put some jughandles in and be done with it. 

These are essentially jughandles.
https://www.google.com/maps/@40.4853807,-74.4223007,3a,60.4y,314.88h,79.07t/data=!3m6!1e1!3m4!1sm38QTADzTPvD8hnaX8ltFg!2e0!7i16384!8i8192

I love that the standard Jersey left is basically just every other states' unofficial impatient left turn. Aka, "this left turn signal fucking blows, I'm going right and banging a uey".

That sounds more like a Michigan left.

[jakeroot]

Put some jughandles in and be done with it. 

These are essentially jughandles.
https://www.google.com/maps/@40.4853807,-74.4223007,3a,60.4y,314.88h,79.07t/data=!3m6!1e1!3m4!1sm38QTADzTPvD8hnaX8ltFg!2e0!7i16384!8i8192

I love that the standard Jersey left is basically just every other states' unofficial impatient left turn. Aka, "this left turn signal fucking blows, I'm going right and banging a uey".

That sounds more like a Michigan left.

Fundamentally they're very similar: an indirect left.

[tradephoric]

At some point in the near future, the people of Prince William County, Virginia will bear witness to a great revolution in traffic engineering. The VDOT plans to turn the current intersection between the Prince William Parkway and Clover Hill Road into a Bowtie Intersection and it is a thing of beauty


2 roundabouts will be installed on Clover Hill on opposite sides of the Parkway. All Left Turns at the main intersection will be prohibited and instead drivers will use the roundabouts to make a u turn to complete their movements. It's essentially an at-grade version of a dogbone interchange. It means the main intersection can use a simple 2 phase signal. It improves traffic capacity and safety.

There are many so-called innovative intersections that do the same thing such as the RCUT, the Michigan Left, the Jughandle, and the Continuous Flow Intersection, but those require a massive amount of right-of-way. This does not, in fact, as you can see, by getting rid of the need for left turn lanes, it takes up less space than a conventional intersection. I hope that this is the beginning of a glorious revolution.

Here's a Median U-turn intersection in Michigan with the same median width as Prince William Pkwy.  Admittedly I'm a little partial to Median U-turns but i don't see much advantage going with the BowTie intersection in the OP's example.


https://www.google.com/maps/@42.7520685,-83.2466276,545m/data=!3m1!1e3

[kernals12]

Notice those loons. That means traffic going straight on the main road has to stop for those making a u turn. With the bowtie, all movements are done on the minor road so the smooth procession of traffic on the major road is uninterrupted.

[hotdogPi]

Notice those loons. That means traffic going straight on the main road has to stop for those making a u turn. With the bowtie, all movements are done on the minor road so the smooth procession of traffic on the major road is uninterrupted.

The U-turn points usually aren't signalized; this one appears to be a rare exception. Usually, if you're on the U-turn ramp, you just merge when you can. (Some median U-turn intersections add a lane for U-turners so that they don't have to wait for a gap in traffic.)

[tradephoric]

Notice those loons. That means traffic going straight on the main road has to stop for those making a u turn. With the bowtie, all movements are done on the minor road so the smooth procession of traffic on the major road is uninterrupted.

The signalized crossovers are coordinated with the main signal so if you get stopped at the crossover you would have gotten stopped at the main signal anyways.  The only main-street drivers delayed by the crossover are those wishing to make a right turn onto the side-street (and that's assuming there isn't a "no right turn on red" sign).

[ErmineNotyours]

kernals12 got called out by CityNerd:

[MCRoads]

I did not know about this intersection. I learned about it from this v. I really hope this isn't built. If you really want a 2 phase inters, just make a superstreet. Which, BTW, wasn't mentioned in the video. You can absolutely make a median U turn wide enough for trucks, despite what VDot is evidently claiming.

[kernals12]

kernals12 got called out by CityNerd:

He doesn't give any explanation for why it's a bad design. Clearly the people who watch his channel are just supposed to know why it's bad. It's an echo chamber

[jeffandnicole]

kernals12 got called out by CityNerd:

He doesn't give any explanation for why it's a bad design. Clearly the people who watch his channel are just supposed to know why it's bad. It's an echo chamber

He seemed to be high on Diamond Interchanges at the beginning of the video because people could make left turns.  The rest of the video tended to poo-poo any interchange design if it didn't require all movements to make standard left turns.

[kernals12]

kernals12 got called out by CityNerd:

He doesn't give any explanation for why it's a bad design. Clearly the people who watch his channel are just supposed to know why it's bad. It's an echo chamber

He seemed to be high on Diamond Interchanges at the beginning of the video because people could make left turns.  The rest of the video tended to poo-poo any interchange design if it didn't require all movements to make standard left turns.

So he's advocating *for* more car accidents?

[kphoger]

So he's advocating *for* more car accidents?

Only inasmuch as you're advocate for pedestrian fatalities.

[1995hoo]

I did not know about this intersection. I learned about it from this v. I really hope this isn't built. If you really want a 2 phase inters, just make a superstreet. Which, BTW, wasn't mentioned in the video. You can absolutely make a median U turn wide enough for trucks, despite what VDot is evidently claiming.

A reason for not doing so is the following two points. For what it's worth, the speed limit on there is 55, but traffic typically moves closer to 70 mph. I try to keep it to 60—65 when I go through that area and I don't wind up passing very many people at all. So that's a reason not to want trucks making U-turns across the median and trying to accelerate into traffic when they can.

Notice those loons. That means traffic going straight on the main road has to stop for those making a u turn. With the bowtie, all movements are done on the minor road so the smooth procession of traffic on the major road is uninterrupted.

The U-turn points usually aren't signalized; this one appears to be a rare exception. Usually, if you're on the U-turn ramp, you just merge when you can. (Some median U-turn intersections add a lane for U-turners so that they don't have to wait for a gap in traffic.)