CD lanes not separated by barriers

[tradephoric]

Here's a parclo B4 interchange in Maryland with collector distributor (CD) lanes not separated by barriers. 

https://www.google.com/maps/@39.1178015,-77.0706905,3a,75y,282.35h,86.52t/data=!3m7!1e1!3m5!1sC3qjN03ntaO59EeMxffUKQ!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3DC3qjN03ntaO59EeMxffUKQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D303.56027%26pitch%3D0!7i13312!8i6656

[briantroutman]

There are two back-to-back not far from my hometown: I-80 at US 15 and I-80 at I-180. Both are currently full eight-ramp cloverleaves (cloverleafs?) without so much as a crumpled plastic bollard separating them from the through lanes. In my experience, the vast majority of motorists ignore the double solid white line and cross them to merge into the through lanes–particularly if they're behind a slowly accelerating truck.

Both interchanges lacked C-D lanes until a major reconstruction project around 2002-2003 when both interchanges' overpasses as well as the Susquehanna River bridge between them were all replace to accommodate the additional lanes.

[davewiecking]

Actually, the GA Ave South (Wheaton) lane only exits, so this isn't a true CD lane-it's an incredibly long exit lane. However-check out the Beltway near FedEx Stadium (Arena Drive exit).

[TravelingBethelite]

A large portion of the C/D (actually the ♦ lanes) lanes here in CT are seperated by no more than 2" tall/4' wide strips of pavement.

[1995hoo]

Capital Beltway at Landover Road (Exit 17) in Maryland. Just some solid lines separating the C/D lanes, with the left C/D lane doubling as a thru lane.

[tradephoric]

Here are two similar capacity interchanges, one with the off-ramp lane separated by jersey barrier and the other separated by just pavement markings.  Is there any research out there that indicates one design is inherently more dangerous than the other?


https://www.google.com/maps/@42.138629,-83.2416897,196m/data=!3m1!1e3


https://www.google.com/maps/@39.1181749,-77.0748266,212m/data=!3m1!1e3

[jakeroot]

Is there any research out there that indicates one design is inherently more dangerous than the other?

I would imagine that the jersey barrier is the preferred separation device only because it forces traffic to use the C/D lanes, whereas simple paint markings allow drivers to mis-behave.

California separates some of their express lanes with plastic bollards to prevent unwanted lane changes due to ... indecisiveness?

If safety isn't an immediate issue, these seem like a good compromise (91 Freeway outside Yorba Linda):

[roadfro]

The express lanes on I-15 in Las Vegas used to have white plastic bollards, similar to the 91 Freeway.  When NDOT did a resurfacing project a few years ago, they decided not to put them back in...too many people striking them. Now, there is just a buffer separation, which is ignored by some drivers–doesn't help that NDOT is not using true double solid white lines here. (Those express lanes will eventually be converted to HOV lanes anyway, so it's not a huge deal to correct the issues.)

[BrianP]

Another one in MD is I-95 @ MD 24:
https://www.google.com/maps/@39.4573872,-76.309241,3a,75y,243.96h,76.25t/data=!3m7!1e1!3m5!1s2ORaFxX_4wRw-qVoZHs-uQ!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3D2ORaFxX_4wRw-qVoZHs-uQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D107.1965%26pitch%3D0!7i13312!8i6656

[cbeach40]

Ontario has flushed paved medians on Highway 402 approaching the Blue Water Bridge.
https://goo.gl/maps/S3o9fe8Hf2k

The three leftmost lanes are dynamically assigned, though typically it's: Cars to USA  -  Trucks to USA (2 centre lanes)  -  local traffic. The through traffic is very much set for the three left lanes while the right lanes is a local collector.

[jeffandnicole]

I-295 at Rt. 9 in Delaware, in 3 of the possible 4 directions. (295 South, 295 North, 9 North): https://goo.gl/maps/dRjXTZmuDi92

[cpzilliacus]

I-95 at Exit 109 (Elkton) in Cecil County, Maryland has a low, low concrete "curb" between the three through lanes and a "C-D" lane (Google here).