Using a collector/distributor lane to pass mainline traffic: Yea or nay?

[roadfro]

I would have no qualms about using a C/D exit for for the purposes of bypassing exceedingly bad traffic on the mainline, provided there is no sign prohibiting the practice.

Perhaps this has been discussed before, but what about using a full-fledged exit to bypass traffic?

I actually used to do this on an infrequent basis...

During the summer before I started college in 2001, I worked in Henderson and lived in northwestern Las Vegas. My typical commute home in the heart of rush hour would take me up I-15 north to US 95 north. At the time, US 95 was only 3 lanes plus ramp-to-ramp auxiliary lanes with little/no shoulder lanes (these were sacrificed to install the auxiliary lanes). This was the worst freeway stretch in the valley at the time due to the 1990s/early 2000s population/housing boom in the northwestern part of town. The transition from I-15 north to US 95 north narrowed from a two lane ramp dumping into a single exit only lane, which would back up the mainline there. High congestion and lack of shoulders downstream meant that any accident would have a crippling effect on the freeway, often with all lanes grinding down to a slow crawl.

At the time, the four consecutive exits from Rancho Drive (exit 77) to Jones Blvd (exit 80) were in a standard diamond configuration in the northbound direction. Thus, it was possible to exit, drive straight through at the cross street, re-enter, and ride the exit-only lane to the next exit to repeat the process. A lane use sign on each exit allowed the maneuver (except at Rancho, where there was no sign--and it involved a dodge around a median island that protruded slightly into an otherwise straight path, but was not designed to prohibit the movement). The tricky thing was that each of these exits was a major arterial street, and the ramp was controlled by a traffic signal. Cutting through at the light was a risk, because if you didn't time it right, you'd be stuck for a cycle--if the freeway wasn't as jammed up as you thought, you could end up losing ground if you caught the light wrong.

Sometimes, this was a little game of cat and mouse for me--I'd keep my eye on a car or two still on the freeway, and see if I actually jumped ahead. Other times, I would just catch things horribly and decide instead to divert to surface streets instead. This whole game is not necessary anymore--since the mainline widening of US 95 was completed circa 2005 (now 4-5 lanes, 1 HOV, auxiliary lanes, and proper shoulders), the backups I'd experienced 14 years ago are relatively few and far between.

[GCrites]

Though it wasn't a C-D technically, I used to act like I was getting onto I-670 W from I-71 N using its left exit in Downtown Columbus. But, I would mash the throttle on my IROC-Z up to about 100mph and just get back onto I-71 N on a ramp intended to carry I-70 E traffic onto I-71 N via the 670 W exit. I called it the Warp Zone. Now that move is impossible due to interchange reconstruction.

[KEK Inc.]

I only know of one intersection that prohibits C/D cutting.



I generally do it northbound on I-5 into Seattle.  The I-90 C/D lanes are faster for I-5 North, and depending on construction I-705's C/D lanes are faster than I-5 mainline.

[cpzilliacus]

The rest area/welcome center on I-66 just east of Manassas suffers from that problem. It's dangerous because the route people use to do this goes directly through where the trucks parallel-park. The rest area signs have auxiliary white signs beneath them saying something like "Rest Area Traffic Only/No Thru Traffic." I think I have a picture somewhere; if I can find it in my Photobucket, I'll come back and edit this post.

Edited to add: Here it is. The people who cut through the rest area drive straight through between the trucks ahead.

I have seen more than one "near miss" crash of idiots in a hurry jumping the queue westbound in the afternoons at this location.

I believe it is generally legal to use C-D lanes like that, though it does not improve overall freeway performance at all, and generally makes it worse.

[KEK Inc.]

That's more of exiting the freeway and re-entering rather than C/D cutting. 

I went to a music festival in Central Washington this weekend, and we got stuck in 80 miles of bumper-to-bumper traffic on I-90 westbound (turns out 20,000 people clogs that freeway on a Sunday afternoon).  I noticed a lot of people exiting and re-entering the freeway.

[froggie]

I believe it is generally legal to use C-D lanes like that, though it does not improve overall freeway performance at all, and generally makes it worse.

This.  And it's for this reason that FHWA generally discourages signing the C/D road as a "through lane", though there are a few exceptions to that (most notably on the DC Beltway in Largo).

Is it legal?  In most cases, yes.

Is it an asshole move?  Yep.

[texaskdog]

In Texas with our fast frontage roads it is easy.  I used to do it all the time, as long as I didn't have to budge when I came back in (when it added a lane).  I've seen people get into those lanes and not exit and just budge in later and I hate that, but I will use frontage roads.

[texaskdog]

Texas has right turn lanes that also go straight.  Is it wrong to cut through the corner lot?  I do that all the time too, since Austin's lots are all built to increase traffic jams.

[intelati49]

Several months ago, I ran across this project for the Poplar Street Bridge in STL that is this exact topic.

See page 12 (14 on PDF) http://www.modot.org/stlouis/major_projects/documents/EWGPSBReportHDR12Sep2012-Final.pdf

I haven't seen the STIP confirming the project, but I believe the plan is to shift the bridge to add an additional lane (5x4 from 4x4) and to add a C-D lane for the Last Missouri Exit. It will not be signed, but the report said that drivers will eventually figure out that they can reenter the highway if they take the "Exit"

Edit: PDf p13 http://modot.org/plansandprojects/construction_program/STIP2016-2020/documents/Sec045SLPaymentsandProjects.pdf

"Bridge, ramp and capacity improvements from 4th Street to Illinois on the eastbound
Poplar Street Bridge and approaches. $8,000,000 IDOT funds for construction"

Going to assume that is the project

[Dr Frankenstein]

All C/D roads in Québec are posted at 70 km/h (45 mph) or 50 km/h (30 mph), so traffic has to be pretty bad for them to be of any use (and they'll very likely be congested anyway).

I've "ramped" through a diamond interchange to pass a snow plow before.

[Brandon]

There are some signed for it: I-88 at IL-83.
And there are some with a penalty for doing so: I-80/294 at IL-1.

It's legal in both cases, the second one just carries the penalty of an extra toll paid for doing so.

[dfwmapper]

Texas has right turn lanes that also go straight.  Is it wrong to cut through the corner lot?  I do that all the time too, since Austin's lots are all built to increase traffic jams.

Are you talking about cutting through a parking lot to avoid a light when turning? That is illegal.

Sec. 545.423.  CROSSING PROPERTY.  (a)  An operator may not cross a sidewalk or drive through a driveway, parking lot, or business or residential entrance without stopping the vehicle.

(b)  An operator may not cross or drive in or on a sidewalk, driveway, parking lot, or business or residential entrance at an intersection to turn right or left from one highway to another highway.

http://www.statutes.legis.state.tx.us/Docs/TN/htm/TN.545.htm

[TheHighwayMan3561]

In the temporary six-lane squeeze configuration of MN 100 being used between 36th St and I-394 in St. Louis Park until the road could be properly rebuilt and widened, southbound the third lane drops at MN 7 into a C/D lane for Minnetonka Blvd and MN 7 traffic getting onto MN 100. That was the one example locally where the C/D lane was abused heavily as a "third lane".

[Super Mateo]

I tried this once at I-80/94 westbound at Torrence when it used to be a cloverleaf.  It didn't save enough time to warrant doing it again, and merging back in at the end of the C/D lane was a headache.  I should have just exited and followed US 6 instead.  I also once tried "Diamond Hopping" on I-94 (Dan Ryan) southbound (signed east) to get around slow/stopped traffic.  Simply exit at each diamond, go straight at each light, then go up to expressway speed on the return ramp.  Exit at next diamond, repeat.  It worked well, other than the occasional stop, until I got to 63rd Street and there was no return ramp.  Never did that again.

[Tom958]

I used to do it as a rule on I-85 northbound as it joined I-75 heading into downtown Atlanta. Up until a couple of years ago, the right lane of 85 ended at the reverse gore with 75, causing both capacity and safety (or, at least, scariness) problems which made bypassing the area via the lightly-traveled CD road a more attractive option. The situation was eventually addressed by dropping an additional lane at the ramp from 75 onto the CD, thereby eliminating the need for the lane drop on 85-- that's what Google now shows.