Double Left Turn Lanes Followed by Lane Drops

[webny99]

What are some cases where there are two left turn lanes that funnel into a single through lane after the turn?
NY 260 at NY 31, Brockport, NY
Hwy 6 at Hwy 5, Hamilton, ON
NY 15A at I-390, Brighton, NY

It's hard to get both the double turn lane and the following lane merge in a single street view image, so you'll need to pan around the corner to see the lane drops in each case. The only criteria is that the lane drop must be within 1/3 mile of the intersection.

What are your thoughts about these scenarios? It can come as quite a surprise to come around the corner and find that your lane ends. Further, if volumes warrant two turn lanes, it suggests, to me anyways, that the volume should certainly warrant two lanes on the road you're turning onto.

[MNHighwayMan]

I don't see it as problematic. It seems like a great solution to add left-turn capacity where you don't have the length for only one left turn lane, but have enough width for two shorter ones. Doing it that way also has the added effect of having a shorter protected left phase, as approximately twice the amount of vehicles can clear the intersection in the same amount of time. The only problem might arise if there isn't enough room past the intersection for efficient merging, but in my experience in these situations, that hasn't been an issue.

[Brandon]

It's an IDOT SOP apparently.

I can name two off the top of my head that IDOT very unwisely installed.  Left turn from US-30 W to West Frontage Road and from US-30 W to westbound Renwick Road, both in Plainfield, IL, as part of the US-30 widening in the area.  Given the way the locals have a lack of merging skills, it's not a wise idea, IMHO.

[jeffandnicole]

I see no problem with this setup as well.  As mentioned, it allows for shorter green arrow situations.

1/4 to 1/3 mile is a lot of distance from what I'm used to.  I've seen them as short as a few skip lines (100 - 200 feet).

[jakeroot]

I don't see it as problematic. It seems like a great solution to add left-turn capacity where you don't have the length for only one left turn lane, but have enough width for two shorter ones. Doing it that way also has the added effect of having a shorter protected left phase, as approximately twice the amount of vehicles can clear the intersection in the same amount of time. The only problem might arise if there isn't enough room past the intersection for efficient merging, but in my experience in these situations, that hasn't been an issue.

This is exactly the reason they're installed.

Agencies typically have two styles of left turns: single lane pro/per, and double lane pro-only. While I have my reservations with pro-only double left, a double left turn of any style can double the capacity of a left turn without any additional signal length.

Much like in Illinois (and other parts of the country, I'm sure), WSDOT installs these all the time (especially at on-ramps). Here's an example: https://goo.gl/geX6oo

The great thing about these is that drivers will instinctively start to create a gap after the left turn, so everyone can smoothly merge together.

[webny99]

I've seen them as short as a few skip lines (100 - 200 feet).

Seeing is believing 



I don't have a major beef with this setup, but as I mentioned above, to me it suggests that either a] the signal cycle is too long or b] the lane drop should not be occurring. In the first two links in the OP, for example, I think a widening to four lanes (over a longer distance - perhaps several miles) is in order.

[MNHighwayMan]

The great thing about these is that drivers will instinctively start to create a gap after the left turn, so everycan can smoothly merge together.

It might be somewhat an expectation of the drivers themselves, but it's also simple geometry: drivers in the right lane will create larger gaps than the ones in the left lane due to the fact that the right lane has a longer physical distance to travel. This promotes the creation of gaps for traffic to merge together beyond the turn.

[jakeroot]

I've seen them as short as a few skip lines (100 - 200 feet).

Seeing is believing 

One very short merge existed in Fife, WA: ~84 feet: https://goo.gl/CKMCZD (removed about a year ago in place of a right turn only)

[jeffandnicole]

I've seen them as short as a few skip lines (100 - 200 feet).

Seeing is believing 



I don't have a major beef with this setup, but as I mentioned above, to me it suggests that either a] the signal cycle is too long or b] the lane drop should not be occurring. In the first two links in the OP, for example, I think a widening to four lanes (over a longer distance - perhaps several miles) is in order.

Here's one example that measures in at 230 feet or so.

You don't need several miles after a double turn lane. 

Edited for Google Maps Link: https://goo.gl/maps/S6TmRzEXy622

[jakeroot]

Another pretty short one. The left turn from Main Street onto the Dunsmuir Viaduct in Vancouver: https://goo.gl/aQQaEG

56 feet! (at least to the de facto merge point). I make this left often enough. It can be quite hairy due to the barriers on either edge. The merge used to be wider, but a two-way bike path was installed, narrowing it down considerably.

[doorknob60]

There's one turning from WB Franklin Rd to SB Cloverdale Rd in Boise. This intersection was recently re-done and Cloverdale north of Franklin was widened to 5 lanes. I assume the eventual goal is to continue widening it south of Franklin, but that would involve an expensive overpass replacement over I-84, which is probably the reason it's still 2/3 lanes there. I like it, because 80% of the cars pile into the leftmost lane (this applies to traffic turning left from Franklin, and thru traffic on southbound Cloverdale) and I can take the right lane and get through the intersection quicker then just merge in afterwards.


Google Maps Link

Side note, I don't stop at that gas station anymore, because there is no legal way to exit that gas station onto Cloverdale SB. It's RIRO onto Franklin (both exits!) and Cloverdale, and there's no U-Turns allowed at the signal (though it's not signed to my knowledge, it is illegal in Boise even though it's not illegal at a state level; I've done it and will probably do it in the future when there's no sign, but it is a kind of tight U-turn regardless).

[Brandon]

The great thing about these is that drivers will instinctively start to create a gap after the left turn, so everycan can smoothly merge together.

[jakeroot]

The great thing about these is that drivers will instinctively start to create a gap after the left turn, so everyone can smoothly merge together.

[rofl x20]

Disclaimer: drivers in the PNW actually know how merges work. My statement does not apply to "the Middle" .

[jp the roadgeek]

There's one in Southington, CT on CT 10 just north of the I-84 interchange.  It's a double left turn onto Spring St.  The lanes merge together after about 100 ft, and before a traffic signal where many turn into BJ's.  If you look at the picture, the merge point is about even with the Staples building. 

https://goo.gl/maps/HyXFUXCWQf32

The ridiculous thing is that you have a double left turn lane to enter Spring St, but a single lane to return to CT 10, which is very frustrating for cars that want to go right on red, but can't when a left turning car or one going straight across prevents them. It often backs up beyond the Staples building, which makes it a nightmare for traffic headed for CT 10 exiting the Chili's/Staples plaza, or for traffic headed either way from the Bertucci's or Bedding Barn on the other side of the road.  In the GSV, I'll bet the white SUV and minivan get in a drag race for who gets to the merge point first (a very common occurrence)

[Revive 755]

I've seen them as short as a few skip lines (100 - 200 feet).

Seeing is believing 

There used to be one with only three skip dashes on NB IL 25 at the southern Stearns Road intersection (Streetview), but that stretch has since been widened.

Then there's IL 62 eastbound to both SB and NB IL 53, where there are no skip dashes after the turn.  Google aerial photo.

[Super Mateo]

It's an IDOT SOP apparently.

I can name two off the top of my head that IDOT very unwisely installed.  Left turn from US-30 W to West Frontage Road and from US-30 W to westbound Renwick Road, both in Plainfield, IL, as part of the US-30 widening in the area.  Given the way the locals have a lack of merging skills, it's not a wise idea, IMHO.

That same IDOT managed to put a SPUI in place at I-80/94 and Torrence where this happens in all four directions.  However, the Torrence ones are three lanes to two, so it's probably not what the OP is looking for.  The east/west lane drops are on the ramps, and both directions deal with extra merging from both sides as they approach the freeway.

The great thing about these is that drivers will instinctively start to create a gap after the left turn, so everycan can smoothly merge together.

Agreed.  In Chicagoland, I'm not sure many of these people have even noticed a lane has ended.  When their lane ends, they never signal and they never look to see if they're cutting someone off.

[webny99]

Here's one example that measures in at 230 feet or so.

Did you mean to add a link?

You don't need several miles after a double turn lane.

Not solely for merging purposes, no. But the fact that two turn lanes are needed suggests that volumes are such that a widening might be in order.



As far as three lanes to two, I won't rule those out. They create their own set of challenges and additional conflict points, so are still relevant. However, what would be really interesting is three left turn lanes followed by a lane drop. NY 441 does this at I-490, but I think it's more than 1/3 mile.

[Buck87]

This one in Sandusky, Ohio lasted only a short while. It was setup when the US 250 (Milan Rd) intersection with Strub Rd was redone a few years ago, but apparently it was causing too many problems, as it has since been converted to a single turn lane by covering the right most left turn lane with white chevrons and bagging its signal.

[jeffandnicole]

Here's one example that measures in at 230 feet or so.

Did you mean to add a link?

You don't need several miles after a double turn lane.

Not solely for merging purposes, no. But the fact that two turn lanes are needed suggests that volumes are such that a widening might be in order.

Yep...completely forgot the link: https://goo.gl/maps/S6TmRzEXy622 .  Original post has been edited for it as well.

2 turning lanes also allows for a shorter left green arrow time, which gives more time for the opposing thru direction.  So the volume of traffic turn left may not warrant 2 thru lanes further down; it's more to assist the road the turning lanes are on.

[7/8]

Here's one: Turning from Shadeland Ave NB to the I-70 WB on-ramp in Indianapolis
https://goo.gl/maps/EjofHF9E8Mn

I can't think of any in my area. If they had these were I live, I feel like everyone would just pile up into the left lane to avoid having to merge. Also, since my area doesn't allow double-permissive-lefts, this would also take away the ability to do a permissive left (which would suck, especially in off-peak hours).

[webny99]

I can't think of any in my area.

Hwy 6 at Hwy 5, Hamilton, ON

This is from the OP - does that not qualify as "your area"? 

[freebrickproductions]

There's a couple here in Huntsville, AL. First one is at Oakwood Avenue and Lee High Drive for traffic turning from Oakwood Avenue westbound onto I-565 westbound:
https://www.google.com/maps/@34.7489607,-86.5781313,191m/data=!3m1!1e3

There's also the triple left turn at US 72 and Moores Mill Road where the right-most lane becomes a Right Turn Only Lane about a third of a mile away from the intersection:
https://www.google.com/maps/@34.774788,-86.5388384,465m/data=!3m1!1e3
(You'll probably need to turn off 3D imagery on Google Maps satellite to see it, though it's also visible on street view)

The only other one I can think of is at Memorial Parkway and Martin Road, but that's due to construction on the Parkway forcing a lane drop shortly after the intersection for traffic turning south from westbound on Martin Road more than anything else, and it's only temporary.

[Michael]

There's a few of these in the Syracuse area:

These two I know of off the top of my head:
Hiawatha Blvd at I-81 north
Bridge St at I-690 (This one is relatively new, and I only know of this one because I recently turned here)

I looked for some more, and I found these:
7th North St at I-81 north
7th North St at I-81 south
West Genesee St at NY 5 (I forgot about this one since it's relatively new too!  It was created so traffic from the ramp on the right doesn't have to merge.)

The ramp from NY 5/92 west to I-481 north is a double lane right turn, but is annoying since the right lane ends and it can be quite busy at times.

[jwolfer]

What are some cases where there are two left turn lanes that funnel into a single through lane after the turn?
NY 260 at NY 31, Brockport, NY
Hwy 6 at Hwy 5, Hamilton, ON
NY 15A at I-390, Brighton, NY

It's hard to get both the double turn lane and the following lane merge in a single street view image, so you'll need to pan around the corner to see the lane drops in each case. The only criteria is that the lane drop must be within 1/3 mile of the intersection.

What are your thoughts about these scenarios? It can come as quite a surprise to come around the corner and find that your lane ends. Further, if volumes warrant two turn lanes, it suggests, to me anyways, that the volume should certainly warrant two lanes on the road you're turning onto.

Pretty common with turns on to freeway entrances..

Z981

[7/8]

I can't think of any in my area.

Hwy 6 at Hwy 5, Hamilton, ON

This is from the OP - does that not qualify as "your area"? 

I didn't notice that you posted that . I was thinking of KW, but it's true that Hamilton isn't too far.