Partially shared turn lane

[jakeroot]

Not seen anything like this before. Thought it deserved its own topic.

Here in Okinawa, there is a stretch of road (not named -- Japan rarely names roads) that is very narrow, not quite wide enough for the traffic it needs to move.

Google Maps location: https://goo.gl/maps/nRrrp18BMxtsx6wXA

Previously, the road was designed so that it was five lanes: two through lanes with a right turn lane northbound, and a single through lane and right turn lane southbound. Further south, the road narrowed further, but did have two through lanes (so the road went from two through lanes, to one, and then back to two). Over the last year, the prefecture has been widening the road to accommodate two through lanes throughout with right turn lanes when possible, but they are working with very limited space.

I present to you: the partially shared through / right-turn lane (post continues below pictures):


Akebono, Naha, Okinawa, Japan: Shared Straight/Right Turn Lane by Jacob Root, on Flickr


Akebono, Naha, Okinawa, Japan: Shared Straight/Right Turn Lane by Jacob Root, on Flickr

Same road, same setup, a little further south: https://goo.gl/maps/6JjeWjpf2XmaTB4C9

It's hard to tell from pictures because of the narrowness of cars in Japan, but the right lane is about two-and-a-quarter Toyota Coaster's in width, roughly 15 feet. The left lane is the standard 3 meters (9.8 feet).

The advantage to this setup is pretty interesting. This road is part of a new highway along the coast (with this stretch being repurposed), connecting many different port and freight areas. Many trucks use this road as a result. Because of their width, painting two lanes that are about 7.5 feet wide would have made it a little too narrow for, say, three semi trucks side-by-side. Having a wider shared lane allows trucks to use more of the lane when possible, but still makes room for turning traffic, with the vast majority of vehicles being narrow enough to still pass around each other.

Drivers in Japan are well-versed in the art of courtesy, so this setup works very well in practice. Drivers turning right scoot over as far as possible (something they always do when turning anyways), and this creates plenty of room for traffic to continue through on the left edge of the lane.

General guidance in the US is replacing four lane roads with three lane roads, with bike lanes and a two-way left turn lane in the center. This is fine if the road isn't busy, but sometimes you need two lanes in each direction. Where ROW is extremely limited, this sort of design could be useful, though it requires drivers to not turn from the center of the lane, a very annoying habit in the US / Canada.

[webny99]

Thanks for sharing, jakeroot. This is a really interesting concept. I do support the use of the paved shoulder to facilitate right hand turns wherever possible, and this is basically just a more explicit variant of that. But like you say, I'm not sure drivers in North America would be courteous enough to use it as intended. 

[kphoger]

In my experience, at intersections with a wide approach lane, a lot of traffic leaves room anyway.  Such as here, back before it was restriped.

[webny99]

In my experience, at intersections with a wide approach lane, a lot of traffic leaves room anyway.  Such as here, back before it was restriped.

This type of "wide approach lane" is not often found in New York, or most of the Northeast for that matter.

Roads have either (1) both centerline and shoulder striping (2) centerline striping with no shoulder (example) or (3) no striping at all. I can only think of one counter-example, which bothers me every time I see it and makes me wonder when they're going to add shoulder striping or remove the centerline striping.

[kphoger]

In my experience, at intersections with a wide approach lane, a lot of traffic leaves room anyway.  Such as here, back before it was restriped.

This type of "wide approach lane" does not really exist in New York, or most of the Northeast for that matter.

Roads have either (1) both centerline and shoulder striping (2) centerline striping with no shoulder (example) or (3) no striping at all. I can only think of one counter-example, which bothers me every time I see it and makes me wonder when they're going to add shoulder striping or remove the centerline striping.

Just doing some random poking around Syracuse in GSV:

Granted, this one has a 'NO TURN ON RED' sign, but...  https://goo.gl/maps/AZ9wEmupjG92VW2JA

Or there's... https://goo.gl/maps/ZkQuaoDoGL4x3PdMA

[webny99]

I cited the only one I know of in the Rochester area. Examples can be found, but they are fairly rare.

[jeffandnicole]

New Jersey has a number of wide lanes  that can be used for both straight and turning traffic, although in reality traffic can be somewhat clumsy with them and cars oftentimes will drive directly in the middle, not giving enough room for two lanes.

[jakeroot]

New Jersey has a number of wide lanes  that can be used for both straight and turning traffic, although in reality traffic can be somewhat clumsy with them and cars oftentimes will drive directly in the middle, not giving enough room for two lanes.

Yeah, I've seen plenty of examples in the US of wide lanes that can be used by two lines of cars, if everyone is being courteous. It's just that they are almost never designed specifically for side-by-side driving as in my example here in Japan, they just get used that way by virtue of being wide and drivers (rightfully) not wanting to wait when there is plenty of room to bypass.

[mrsman]

New Jersey has a number of wide lanes  that can be used for both straight and turning traffic, although in reality traffic can be somewhat clumsy with them and cars oftentimes will drive directly in the middle, not giving enough room for two lanes.

Yeah, I've seen plenty of examples in the US of wide lanes that can be used by two lines of cars, if everyone is being courteous. It's just that they are almost never designed specifically for side-by-side driving as in my example here in Japan, they just get used that way by virtue of being wide and drivers (rightfully) not wanting to wait when there is plenty of room to bypass.

The US standard of these types of lanes, seems to be that they are wide enough for one through lane and one parking lane, but not wide enough for two thru lanes of traffic.

For the most part, while a normal sedan is about 6 feet wide and the widest trucks and buses that aren't "wide load" are 8.5 feet wide, typical rules in the US tend to require a moving traffic lane to be 10 feet wide at minimum.  Parking lanes can be set off for as little as 7 feet wide, but 8 feet is a more common standard.

Now, if you have 18 feet between the center line and the curb, that's typically designed as 10 feet thru and 8 feet parking as opposed to two 9 foot lanes.  Most cars would do fine with two nine foot lanes, but it's not the standard.  So we see the typical pattern of driving where drivers will use the center part of the roadway.  Occasionally, some right turners will pull into the parking lane so as not to slow down thru traffic.  Also, if there is a left turner, nimble cars will be able to sneak into the parking lane to go around, but that is only feasible because they use the space available at a lower speed.

But I could not imagine anything similar happening on multi-lane streets in most places. 

NYC used to have something quite interesting on many of the wider crosstown streets.

https://www.nyc.gov/html/brt/downloads/pdf/2011_brt_34th_cb6_slides.pdf

Go to the slide on page 8.

The central part of 34th, between 3rd and 9th Avenues running right through the heart of Manhattan adjacent to Empire State Bldg, Macy's, and Penn Station is 52 feet wide curb to curb.  The old configuration was a 7 foot curb parking lane, a 9 foot driving lane adjacent to the parking lane, and a 10 foot driving lane near the center in both directions.  Given the heavy traffic, very few vehicles would go fast, so they could negotiate the narrower lanes.  Wider vehicles like buses and trucks would straddle both lanes, but it just worked.  Even with the narrow right of way, 6 vehicle lanes were negotiated (two parking and four driving).

As the slides indicate, the new pattern sets out bus lanes and all of the lanes are wider.  One 8 foot parking lane, and four 11 foot driving lanes [or something similar, I can't find precise schematics.]  So now there are only five vehicle lanes and practically half of the parking in this area.  (Parking may be a misnomer, since almost all available spots are limited to commercial delivery loading, but in such a busy area they need more spots for deliveries and one side isn't enough which is why there is so much double parking in NYC.)

So the old configuration squeezed in 6 lanes where the modern configuration (roughly averaging 10 ft per lane) allows only 5 lanes.

[1995hoo]

Heh. Who needs to share a lane? Twice this week on two consecutive days, I was waiting to cross at the crosswalk seen in the Street View link below. I was waiting to the left of the camera viewpoint around where the blond lady dressed in black is standing and I wanted to cross to the right. Both times when I was waiting to cross, I saw someone further back in the line of vehicles pull out over the double yellow line, pass the guy at the front of the line, and make a right turn (not a right on red, either, which is illegal there, but I didn't happen to notice what indicator the traffic light was showing).

https://goo.gl/maps/4exucPxGjZChMbft8

[webny99]

Heh. Who needs to share a lane? Twice this week on two consecutive days, I was waiting to cross at the crosswalk seen in the Street View link below. I was waiting to the left of the camera viewpoint around where the blond lady dressed in black is standing and I wanted to cross to the right. Both times when I was waiting to cross, I saw someone further back in the line of vehicles pull out over the double yellow line, pass the guy at the front of the line, and make a right turn (not a right on red, either, which is illegal there, but I didn't happen to notice what indicator the traffic light was showing).

https://goo.gl/maps/4exucPxGjZChMbft8

I've certainly been tempted to do that before, but don't recall actually doing it. There's one traffic signal near me where I often turn right that has a very long red phase. It's become a bit of a game to avoid getting stuck behind another car, as there's seemingly enough shoulder room to go past right up until the intersection, but there's just a few feet where it narrows up so a single car can block you from turning. This means that, unless that driver notices your predicament and pulls up beyond the stop line, you're stuck waiting a minute plus until the light changes.

Semi-related - this recently revamped intersection has crosswalks that are conveniently set just far enough back that a single car can pull past the crosswalk while waiting to turn right. This means that, if used properly, the marked crosswalk is behind that car while they're waiting to make their turn, so pedestrians can still use the crosswalk. I think it's a great design that reduces potential conflict between cars and pedestrians. Obviously, not all locations have the space or ROW for it to work, but I hope it becomes standard for all crosswalks where space allows.

[Brandon]

New Jersey has a number of wide lanes  that can be used for both straight and turning traffic, although in reality traffic can be somewhat clumsy with them and cars oftentimes will drive directly in the middle, not giving enough room for two lanes.

Yeah, I've seen plenty of examples in the US of wide lanes that can be used by two lines of cars, if everyone is being courteous. It's just that they are almost never designed specifically for side-by-side driving as in my example here in Japan, they just get used that way by virtue of being wide and drivers (rightfully) not wanting to wait when there is plenty of room to bypass.

Sort of like this one in Chicago, a single lane used as two lanes, even under a narrow rail viaduct: https://goo.gl/maps/VHpizCFQJZJhSAGa8

[jakeroot]

New Jersey has a number of wide lanes  that can be used for both straight and turning traffic, although in reality traffic can be somewhat clumsy with them and cars oftentimes will drive directly in the middle, not giving enough room for two lanes.

Yeah, I've seen plenty of examples in the US of wide lanes that can be used by two lines of cars, if everyone is being courteous. It's just that they are almost never designed specifically for side-by-side driving as in my example here in Japan, they just get used that way by virtue of being wide and drivers (rightfully) not wanting to wait when there is plenty of room to bypass.

Sort of like this one in Chicago, a single lane used as two lanes, even under a narrow rail viaduct: https://goo.gl/maps/VHpizCFQJZJhSAGa8

Kind of?

I think the difference with what I've posted in my OP, and the examples posted by users here (including yours), is that in my OP, there is technically just a single lane, but there are separate straight and turn arrows occupying the lane, just on separate edges of the lane. A wider vehicle is legally permitted to travel straight down the center, if they so choose, but they have painted arrows on opposite edges of the lane specifically to encourage traffic to use one of the edge of the lane for going straight, and the other edge for turning.

I think the closest we'd ever see to something like this in the US, would be on roads with parking along either edge, and one lane in each direction. At intersections, the parking would disappear, and you'd see left turn arrows close to the center line, telling traffic turning left to hug the centerline, and then a shared through-right arrow somewhere off to the right, encouraging traffic not turning left to use that edge of the roadway.

More often than not in the US, you'll not see any arrow when a lane goes left, right, and straight, or you'll see that combo left/right/straight arrow. In either case, drivers may actually be obligated (legally) to turn from the proper edge of the roadway, but there's nothing about straight through traffic, so you end up seeing cars that, for whatever reason, decide to wait behind the car turning left or right, even if there is room. Having actual designated arrows on opposing edges of the lane, even if there is no lane line between them, could theoretically encourage traffic to occupy the proper side of the wide lane. And that's kind of the idea in my OP example here in Japan, although it's done mostly for the benefit of trucks and because there is no way to actually fit in two lanes.

[Scott5114]

Heh. Who needs to share a lane? Twice this week on two consecutive days, I was waiting to cross at the crosswalk seen in the Street View link below. I was waiting to the left of the camera viewpoint around where the blond lady dressed in black is standing and I wanted to cross to the right. Both times when I was waiting to cross, I saw someone further back in the line of vehicles pull out over the double yellow line, pass the guy at the front of the line, and make a right turn (not a right on red, either, which is illegal there, but I didn't happen to notice what indicator the traffic light was showing).

https://goo.gl/maps/4exucPxGjZChMbft8

Seems like that'd be a good way to get beaned in the face by someone making a right turn unexpectedly.

[NoGoodNamesAvailable]

Not seen anything like this before. Thought it deserved its own topic.

Here in Okinawa, there is a stretch of road (not named -- Japan rarely names roads) that is very narrow, not quite wide enough for the traffic it needs to move.

Google Maps location: https://goo.gl/maps/nRrrp18BMxtsx6wXA

Previously, the road was designed so that it was five lanes: two through lanes with a right turn lane northbound, and a single through lane and right turn lane southbound. Further south, the road narrowed further, but did have two through lanes (so the road went from two through lanes, to one, and then back to two). Over the last year, the prefecture has been widening the road to accommodate two through lanes throughout with right turn lanes when possible, but they are working with very limited space.

I present to you: the partially shared through / right-turn lane (post continues below pictures):


Akebono, Naha, Okinawa, Japan: Shared Straight/Right Turn Lane by Jacob Root, on Flickr


Akebono, Naha, Okinawa, Japan: Shared Straight/Right Turn Lane by Jacob Root, on Flickr

Same road, same setup, a little further south: https://goo.gl/maps/6JjeWjpf2XmaTB4C9

It's hard to tell from pictures because of the narrowness of cars in Japan, but the right lane is about two-and-a-quarter Toyota Coaster's in width, roughly 15 feet. The left lane is the standard 3 meters (9.8 feet).

The advantage to this setup is pretty interesting. This road is part of a new highway along the coast (with this stretch being repurposed), connecting many different port and freight areas. Many trucks use this road as a result. Because of their width, painting two lanes that are about 7.5 feet wide would have made it a little too narrow for, say, three semi trucks side-by-side. Having a wider shared lane allows trucks to use more of the lane when possible, but still makes room for turning traffic, with the vast majority of vehicles being narrow enough to still pass around each other.

Drivers in Japan are well-versed in the art of courtesy, so this setup works very well in practice. Drivers turning right scoot over as far as possible (something they always do when turning anyways), and this creates plenty of room for traffic to continue through on the left edge of the lane.

General guidance in the US is replacing four lane roads with three lane roads, with bike lanes and a two-way left turn lane in the center. This is fine if the road isn't busy, but sometimes you need two lanes in each direction. Where ROW is extremely limited, this sort of design could be useful, though it requires drivers to not turn from the center of the lane, a very annoying habit in the US / Canada.

This sort of thing is common in Germany. When the road is almost wide enough for 2 lanes but not quite, they will paint the arrows on the floor but no lane lines. Of course Germany has a similar rule-following culture to Japan. If you tried this in America I think a lot of people either wouldn't get the idea or simply wouldn't care.

[jakeroot]

This sort of thing is common in Germany. When the road is almost wide enough for 2 lanes but not quite, they will paint the arrows on the floor but no lane lines. Of course Germany has a similar rule-following culture to Japan. If you tried this in America I think a lot of people either wouldn't get the idea or simply wouldn't care.

That's pretty cool, doesn't surprise me that Germany would also do it. Very auto-focused society, much like Japan. Then again, America is too, but somehow our drivers are mostly complete idiots.

[NoGoodNamesAvailable]

This sort of thing is common in Germany. When the road is almost wide enough for 2 lanes but not quite, they will paint the arrows on the floor but no lane lines. Of course Germany has a similar rule-following culture to Japan. If you tried this in America I think a lot of people either wouldn't get the idea or simply wouldn't care.

That's pretty cool, doesn't surprise me that Germany would also do it. Very auto-focused society, much like Japan. Then again, America is too, but somehow our drivers are mostly complete idiots.

Japan and Germany at least have a safety net of decent public transit service throughout the country. Even though most people choose to drive, every city in Japan and Germany has a usable public transit system, and even rural villages will at least have a bus route with a few runs a day. In America denying somebody a driver's license is a pretty inhumane thing to do even if they're a bad driver. You are basically saying that you are no longer allowed to have a job. Plus if you have ever talked to people who had their license suspended, you'll realize that driving without a valid license is more common than you'd think.