AARoads Forum

National Boards => General Highway Talk => Topic started by: TravelingBethelite on September 21, 2015, 01:15:33 PM

Title: Left exits
Post by: TravelingBethelite on September 21, 2015, 01:15:33 PM
Why are left exits considered substandard? I would assume it's becausing those building the highway want to minimize lane-changing, and therefore accidents. Is there such a thing as a 'safe' left exit?

EDIT: Left exits in the U.S.
Title: Re: Left exits
Post by: AlexandriaVA on September 21, 2015, 01:17:02 PM
I think people in the UK love their left exits!  :sombrero:
Title: Re: Left exits
Post by: jakeroot on September 21, 2015, 01:39:24 PM
Because you pass on the left. Exiting on the left is illogical.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.drivingadvisors.com%2FPassing_lane.jpg&hash=0936d2a8dd573840195c8bca9601bb9198978ad5)
Title: Re: Left exits
Post by: Big John on September 21, 2015, 01:49:38 PM
Left lanes are supposed to be the fast passing lanes, so exiting from or merging onto a left lane can cause more differences in speed of vehicles intermingling.
Title: Re: Left exits
Post by: Rothman on September 21, 2015, 03:18:14 PM
Quote from: Big John on September 21, 2015, 01:49:38 PM
Left lanes are supposed to be the fast passing lanes, so exiting from or merging onto a left lane can cause more differences in speed of vehicles intermingling.

^This.  High speed merges are also probably just unsafe.
Title: Re: Left exits
Post by: SteveG1988 on September 21, 2015, 03:32:32 PM
Left out Right In
Title: Re: Left exits
Post by: jakeroot on September 21, 2015, 03:34:20 PM
I can't help but think left exits hinder the development of proper lane discipline.
Title: Re: Left exits
Post by: TEG24601 on September 21, 2015, 03:40:09 PM
It doesn't make any sense to me either.  The keep out of the left lane argument doesn't hold water either, because the left exits are rarely low speed, they are usually high-speed connections (except for the 90° at the bottom of the ramp on to SR-520 from I-5 in Seattle).


It really should be...


Avoid a left exit, unless the speed limit is 10 MPH greater that the suggested ramp limit, or redesign the left exit to accommodate it.


Of course, left entrance cause issues, because of people merging across to reach the next right Exit, like I-5 between SR-520 and Mercer Street.  However, a relatively minor modification to the express lanes would solve that problem.
Title: Re: Left exits
Post by: jakeroot on September 21, 2015, 04:23:04 PM
Quote from: TEG24601 on September 21, 2015, 03:40:09 PM
It doesn't make any sense to me either.  The keep out of the left lane argument doesn't hold water either, because the left exits are rarely low speed, they are usually high-speed connections (except for the 90° at the bottom of the ramp on to SR-520 from I-5 in Seattle).
...

Avoid a left exit, unless the speed limit is 10 MPH greater that the suggested ramp limit, or redesign the left exit to accommodate it.

The speed of the ramp is irrelevant. What is relevant is what each lane is for: left for passing, right for travel. Exits and entrances from the passing lane make no sense whatsoever. Forcing people (and trucks and other slow-moving vehicles) into the "fast" lane is very dangerous and should be discouraged in every conceivable situation.

The only situation where it's helpful is when there's an HOV lane involved (hence, Texas-T).
Title: Re: Left exits
Post by: roadman65 on September 21, 2015, 04:28:46 PM
Too bad they cannot get rid of those horrible left exits and entrances off the Pulaski Skyway.  The exit off is not bad as the road is two lanes, but merging on is a nightmare as you have no merge area and very poor sight distance after you awkwardly have to look over your right shoulder.

I also remember Miller's West Side Highway was that way in the day it was the main westside freeway in NYC.  In some areas I remember the left lane ended so that new lane could stay continuous at one exit.  I am not sure if that was the case with all ramps on that now long defunct steel and cobblestone viaduct.
Title: Re: Left exits
Post by: vdeane on September 21, 2015, 06:27:38 PM
Apparently, NY freeways don't have passing lanes: http://www.timesunion.com/tuplus-local/article/Trooper-Reader-among-drivers-behaving-badly-6517997.php (to get around the paywall, simply google "Trooper: Reader among drivers behaving badly" and click the result for the Albany Times Union column Getting There)

Quote
"In New York, no roadway is posted more than 65 mph, so it appears that all drivers were exceeding the posted speed limit as the scenario is described," Cepiel said. "In New York state, it is in fact permissible to drive in the left lane of a divided highway unless otherwise designated by signs such as 'Keep right except to pass' or 'Slower traffic keep right.' These signs will be present on portions of the Thruway but are not present on the Northway or I-90 east/west in the greater Albany area, which again may or may not be the roadways the writer mentioned. Also, as a visual, most roadways that have slow-moving lanes going up hills, mountains, steep inclines, etc. will have signs such as this."

Vehicle & Traffic Law Section 1123 permits motorists to pass in the right lane of a divided highway as long as they are not exceeding the posted speed limit and the passing can be done safely, he noted.

"The writer in this case would be considered to be an aggressive driver as she was engaging in multiple violations and/or acts which not only endangered other motorists and created a possible accident scenario, but she was imposing her will upon another motorist by flashing her lights and possible tailgating in an attempt to move a motorist over who was already speeding and may or may not have been obligated to be in the rightmost lane, again, depending on which roadway she was on," he said.
Title: Re: Left exits
Post by: empirestate on September 21, 2015, 07:35:45 PM

Quote
"In New York state, it is in fact permissible to drive in the left lane of a divided highway unless otherwise designated by signs such as 'Keep right except to pass' or 'Slower traffic keep right.'

...or unless driving at less than the normal speed of traffic. [Sec. 1120(b)]

http://codes.lp.findlaw.com/nycode/VAT/VII/25/1120


iPhone
Title: Re: Left exits
Post by: peterj920 on September 22, 2015, 06:48:43 AM
Milwaukee, WI had left exits at every major freeway interchange.  At the time, it was done because the left exits were cheaper to construct since the bridges didn't have to be as long.  They are now being replaced with right exits because people were weaving throughout the freeway to get to the appropriate exit, which was slowing down traffic.  With right exits, all of the traffic that has to exit knows where to go and traffic on the left can continue uninterrupted.  With left exits, both sides of the freeway became congested since there were exits on both sides.

Interesting enough, a left exit was built at this directional T interchange of US 10/45 near Winchester, WI 12 years ago.  The interchange is located near wetlands, and was probably constructed with left exits to save on land and on cost.  The state wanted to provide a high speed interchange, but constructed it this way because the interchange is rural, and the traffic isn't very heavy so they felt that a left exit wouldn't interrupt the flow of traffic. 

https://www.google.com/maps/@44.2092353,-88.677541,3a,75y,260.72h,83.24t/data=!3m6!1e1!3m4!1sA8KgfR42Ejz3SDJYxH973w!2e0!7i3328!8i1664?hl=en
Title: Re: Left exits
Post by: ET21 on September 22, 2015, 12:19:57 PM
Left exits are one of the main reasons why I-290 in Chicago backs up every single day
Title: Re: Left exits
Post by: kkt on September 22, 2015, 04:40:31 PM
It's the weave when a right entrance is followed by a left exit.  If the left exit was all by itself with no other entrances or exits for miles, it wouldn't be a problem.  Unfortunately, the left exits tend to be built in cities where the exits are crowded anyway.

In Seattle on I-5 southbound, the weave between the left entrance for traffic from SR 520 and the right exit at Mercer Street is the single worst bottleneck.  Even worse than where I-5 narrows to 2 lanes.
Title: Re: Left exits
Post by: bzakharin on September 22, 2015, 04:58:12 PM
Quote from: vdeane on September 21, 2015, 06:27:38 PM
Apparently, NY freeways don't have passing lanes: http://www.timesunion.com/tuplus-local/article/Trooper-Reader-among-drivers-behaving-badly-6517997.php (to get around the paywall, simply google "Trooper: Reader among drivers behaving badly" and click the result for the Albany Times Union column Getting There)

Quote
"In New York, no roadway is posted more than 65 mph, so it appears that all drivers were exceeding the posted speed limit as the scenario is described," Cepiel said. "In New York state, it is in fact permissible to drive in the left lane of a divided highway unless otherwise designated by signs such as 'Keep right except to pass' or 'Slower traffic keep right.' These signs will be present on portions of the Thruway but are not present on the Northway or I-90 east/west in the greater Albany area, which again may or may not be the roadways the writer mentioned. Also, as a visual, most roadways that have slow-moving lanes going up hills, mountains, steep inclines, etc. will have signs such as this."

Vehicle & Traffic Law Section 1123 permits motorists to pass in the right lane of a divided highway as long as they are not exceeding the posted speed limit and the passing can be done safely, he noted.

"The writer in this case would be considered to be an aggressive driver as she was engaging in multiple violations and/or acts which not only endangered other motorists and created a possible accident scenario, but she was imposing her will upon another motorist by flashing her lights and possible tailgating in an attempt to move a motorist over who was already speeding and may or may not have been obligated to be in the rightmost lane, again, depending on which roadway she was on," he said.
Well, technically, you cannot speed while passing (much less pass a speeding car) anywhere, not that anyone adheres to this
Title: Re: Left exits
Post by: noelbotevera on September 23, 2015, 06:59:01 PM
Tell all of this to I-81 around Harrisburg. The I-81/I-83/US 22/US 322 (which I call "The Show", for the Farm Show Complex nearby) and the Eisenhower have some terrible design and it's a left exit for I-81 SB near The Show and PA 581 (which I call "Mr. Megalith") have a left exit from I-81 SB. I-83 suffers from this. PA 581-I-83 interchange is a left exit SB I believe.
Title: Re: Left exits
Post by: capt.ron on September 25, 2015, 10:47:19 PM
The classic I-40 east left exit off of the beltway in Memphis is one of the most brain dead designs ever devised by humans. Did somebody say that there is a proper (RIGHT exit) flyover from the beltway to I-40 east open?
Speaking of I-40, there is a left exit in the state of Oklahoma. I -40 east into Elk City features a left exit.
Title: Re: Left exits
Post by: CtrlAltDel on September 26, 2015, 12:41:45 AM
Quote from: capt.ron on September 25, 2015, 10:47:19 PM
Speaking of I-40, there is a left exit in the state of Oklahoma. I -40 east into Elk City features a left exit.

There's two left exits on I-40 east in Elk City. One coming into town, the other going out. There's also a left entrance too.
Title: Re: Left exits
Post by: CtrlAltDel on September 26, 2015, 01:05:26 AM
Quote from: TravelingBethelite on September 21, 2015, 01:15:33 PM
Why are left exits considered substandard?

The accident rate at left-side exits is about four times higher than it is for right-side exits.