Friday, July 11, 2008

A contrarian look at lane-merging

OK, here's the piece I promised, about lane merging. Note: I don't do this, because the social opprobrium would be overwhelming.

The situation I'm talking about isn't merging onto freeways. (On freeways, one should whenever possible change lanes or slow down to allow the merging vehicle onto the highway. ) I'm talking about when there's an unexpected obstruction in one lane of a multi-lane road or street, such as a stalled car, a moving van or construction.

Just for a minute, think of this situation as a traffic engineer might, viewing the pavement in each lane as "vehicle storage space." If something up ahead is causing traffic to stop or slow dramatically, why should all the vehicles line up in one lane only? That just backs the tie-up even farther down the street. If both lanes were used, with each vehicle fairly and equitably alternating merging, once the obstruction was reached, it would cut in half the length of the clog on the street.

In reality, though, as so many previous comments have shown, people don't act the way engineers view the world. We use our driving as a status quest. People want to be the cutters-off, not the cuttee. They think people who try to cut in front are greedy and ill-mannered. Sometimes, especially when the only vehicle zooming to the head of the formerly empty lane is a gas- and space-hogging Hummer, they are probably right.

Second, this is nothing I thought up in Boston. I noticed it some years back here in Charlotte. In Boston, in such a situation what they do is honk their horns. This is both useless and nuts. I mean, do they think the stalled car will, Lazarus-like, revive itself, or the moving van will decide to go away and come back at midnight, if only it hears some beeping horns?


Anonymous said...

Sorry, but this is just wrong. In fact when people stay in the lane that is ending right up until the last minute it causes a bottleneck and no engineer I know will ever say a bottle neck is a good thing. I have seen this time and time again. If people who are in the lane that is ending would go ahead an merge as soon as they know then you can merge them in smoothly one car at a time while the lane that is not ending keeps moving along, slowly yes, but still moving. However, when they all wait until the last minute you usually get the one over gracious driver who lets 2, 3 or 4 in or they just bulldoze their way in and everything just grinds to a halt.

Considering the way the roads around here are designed (or not) I am not surprised if any road engineer around here would actually advocate waiting until the last minute.

Anonymous said...

I agree with the first poster. It just contributes to people stopping at the front, where they ought to be moving, rather than at the back, where they are likely going to have to be stopped anyway.


Jumper said...

I'm not sure if the length of the slowdown in feet has much to do with it. What's the advantage in a 50 foot slowdown in two lanes versus a 100 foot slowdown in one lane? I just can't see it. It's illegal to block an intersection already.

Fairness is the issue. I always yield to the one who was waiting longer than me. It's usually easy to discern. When it's not, some simple observation can lead to a good guess. People pretty much know when they are cutting in line or when they have been waiting unfairly long.

Northbound Johnston Rd/521 approaching 485, waiting to make a left turn, is a prime example. The turn lane is full of people waiting. Cheaters dash to the front and try to cut in near the traffic light.

Andrew said...

"Considering the way the roads around here are designed (or not) I am not surprised if any road engineer around here would actually advocate waiting until the last minute."

Road engineer around here? HA!

Anonymous said...

The theory that people will always alternatively let people merge in with them in the backed-up lane is a good one but realistically will never work because everyone always thinks their time is more important than everyone else's. I prefer being nice and waiting in the longer lane rather than being a jerk, driving as far as I can in the empty lane, and then try to bully my way in at the end. For those of you who do this, I will never let you in, no matter how long your turn signal has been on, and no matter how close you get to me trying to "make" me let you in. I know you are a cheater, else you wouldn't be in that position. Go to the back of the line like everyone else!

Anonymous said...

I long ago established that given any lane obstruction, the lane I am in will take the longest to clear said obstruction.

A similar grocery check-out law applies as well.


Anonymous said...

It would never work because the people wanting to race ahead and cut over will always outnumber the people who try to be considerate and let others in.
Also, I get incensed at people who take advantage of a temporary third lane (i.e. 51 at Providence Rd.) to avoid waiting in line at the traffic light. Instead they'll get in the extra lane, even though they know it becomes turn-only just past the light, and try to beat the traffic and cut everyone else off. I usually refuse to let the jerks over.

Anonymous said...

I never thought about it in terms of lane storage, so thanks for that interesting view, Mary. I usually try to balance being polite with being a pushover, so I'll try to let one person in while the lanes are still backed up, but not the person who had a clear view of the obstruction ahead and still kept driving right up to the traffic obstruction. And the last time I took pity on a lane-jumper, it let about 5 other vehicles in front, and then traveled VERY leisurely. So when we got to the next light, that vehicle sailed through slowly on the yellow, but I had to stop for the red light.

Anonymous said...

The problem lies here in NC and our road crews. Nowhere have I ever seen such lame attempts to forewarn on coming traffic of construction, lane merges, etc. as I do here in my homeland of the NC.

Anywhere else you drive in the country you are given ample time (like a mile or more) to get your ass over into the appropriate lane. I can't tell you how many times I run up on a utility truck or road construction and the "construction or merge" sign is placed 2 feet behind the vehicle or the area of road being worked on.

Forewarning people, is it too much to ask to have some common sense ?

This is how you avoid bottlenecks. And if you have a mile or more notice everyone has plenty of time to move over and traffic doesn't need to slow down.

Hell, even hillbilly South Carolina can do this right. What's up with NC ?

John said...

"The theory that people will always alternatively let people merge in with them in the backed-up lane is a good one but realistically will never work because everyone always thinks their time is more important than everyone else's."

This poster hit it right on the head... heck we can't get people to do that when it comes to getting out of the church parking lot on Easter Sunday morning!!!

On another point raised in your earlier column about courtesy... are you aware that if you choose to courteously encourage another driver to take an action he is not legally entitled to (i.e. make a left or go at a stop sign, when they don't have the right-of-way) you may very well be held liable for any accident that ensues because another driver who had the right-of-way didn't realize what was happening?

That's exactly right, the rules of the road and right-of-way are not yours to change because you think you are being nice! They are SAFETY regulations and if you ignore them and unintended tragedy occurs, YOU are at fault!

As more and more people enter the nations road nets every day, it becomes ever more important for all of us to understand the rules of the road and follow it AT ALL TIMES. Everybody doing it the right way (as defined in the traffic laws) everytime, makes the roads as safe as they can be.

No, you don't get to make it up as you go along, or to fit your definition of courtesy. It's either right, or all too often, dead wrong!

Anonymous said...

"Anywhere else you drive in the country you are given ample time (like a mile or more) to get your ass over into the appropriate lane. I can't tell you how many times I run up on a utility truck or road construction and the "construction or merge" sign is placed 2 feet behind the vehicle or the area of road being worked on."

I have to disagree with this. Yes you do see this happen in they city, but that is when the activity is taking place within a small portion of a city block or two. I have been on 85, 77 and/or 485 plenty of times where a sign will say 'left lane closed 3 miles', then another electronic sign that says 'left lane closed in 2 miles', then another saying 'left lane closed in 1 mile' and the jacka$$es still wait until the very last minute to get over. You could give these guys 10miles notice and the same thing would happen.

Anonymous said...

I have no problem at all driving on an "empty" lane while the other lane is all backed up, at times for a mile or so.

After I get to the end of the closed lane, I find a hole or open spot and merge right in and go on my way. No problem at all.

What scare the bejeebers out of me is these road ragers, especially big rig drivers, who think they have the right and ungiven authority to BLOCK the open lane preventing other drivers from moving on and thus causing a TWO lanes traffic jam instead of minding his own business and staying in his lane.

I've had to drive around these nutso's so I can merge up ahead and go on my way. I've even been run off the road. I even had one driver chase me on I-40 from Asheville cause he was pissed I dare merge ahead of him.

I have no intention of getting stuck UNNECESSARILARY in stalled traffic while another lane is wide open. This is a waste of gas, unncessarly idling and a waste of time.

All this is needed is both lanes to merge alternatively one vehicle at a time so both lanes can move, not just one.

Anonymous said...

"On freeways, one should whenever possible change lanes or slow down to allow the merging vehicle onto the highway."

Wrong. That might be the "polite" thing to do, but NC traffic regulations state that it is the responsibility of the drivers coming down the on-ramp to yield the right of way to traffic already traveling on the interstate or freeway.

During rush hour traffic, a driver often doesn't have the option of changing lanes (see that big semi right next to your door handle?), nor do they have the options of dropping their speed by 20 mph or more just to let someone onto the freeway.

A lot of people attempting to merge at highway speeds don't even look in their rearview or side mirrors when merging. They just bull their way in, expecting everyone else to accomodate them.

John said...

FYI... Mary, have you discussed this one with the Highway Patrol? I've actually seen people pulled over for doing this!

Jumper said...

This is an interesting philosphical microcosm going here. Anonymous's 3:57 somehow makes me want to be a bit more forgiving of this behavior. Okay, here's the deal: go on to the front of the empty lane, and if you pass 10 cars, just be mentally prepared to wait 10 cars until being assertive. If someone obviously lets you in, no foul.

Anonymous said...

Uh, has nobody heard that you're not really supposed to pass on the right?

So, the whole point is mute. If you're using an empty lane on the right, to pass a line of stopped traffic, that could be considered an "improper use of lane" or an "unsafe pass".

NC Native said...

I have to agree with 12:33pm. This lady is getting ridiculous. The problem with the "vehicle storage space" theory is just that ... it's a theory. In practicality, it's useless because nobody is sitting in their car calculating speed, acceleration, distance, time, etc. so that there is equitable space for cars to merge in an alternating fashion. And no engineer could design traffic flow that could account for such laws of physics. It might solve cutting the length of the clog on the street, but it doesn't mean the time to destination is reduced after taking into account the time delay caused by the lane obstruction. And furthermore, engineers don't think like this theory would suggest. Engineers think in terms of connecting major and minor arteries, traffic-calming measures, and obstructions to and aesthetics for drivers' line of sight. The problem is that Providence road is just like a freeway! You have straightaways on a four-lane road that stretch for 3-4 miles at times through compact single-family residential areas with lanes big enough for semis. You can put up 35 mph signs all day long, but it doesn't matter because the road looks and feels like a 50 mph zone to the driver.

Anonymous said...
This comment has been removed by a blog administrator.
Kat said...

3:42 You ARE permitted to pass on the right but only on roads where there are at least two lanes going in each direction. Look it up in the driver's manual.

Anonymous said...

Slow down on a highway to let someone merge?? Crazy I tell you, and a lot of the reason there so many rear end wrecks on the highway and people die. The people who do this are the ones who make 10 cars behind them stop to let 1 car in so they feel better about them selves, while screwing the 10 jerks behind them. why are they honking at me. give me a break. wake up!!

An Engineer would not think the way you describe because the volume of cars has not changed. If you have 2 glasses, 1 half full of milk and the other empty - you have a half of a glass of milk, if you put a 1/4 in the empty glass, how much milk do you have?? 1/2 a glass. Crying over split milk (people who cut)? will do nothing. Take a little opportunity in life and cut. come on you know you want to.

The reference to people who drive hummers cutting in front of everyone else is ignorant! How do you bring a political statement into a blog on merging traffic I have know idea.

Anonymous said...
This comment has been removed by a blog administrator.
Alan said...

Anonymous 3:27 says "I have no problem driving in an empty lane..."

Please consider the following an answer honestly:

You are going to a movie. There is a line of 10 people waiting to buy tickets. The theater has two ticket windows, side by side, but only one window #1 is open. You get in line to wait your turn. Someone walks up to window #2 the closed one and then steps over in front of the window where you and 10 other people are waiting.

Do you get mad?

Afterall, there was "empty space" in front of the ticket window.

If you step up to ask the line cutter to wait his turn, are you a "nutso, theater rager, line nazi?

Be honest now.

Anonymous said...


Not when your lane is going away.

Ask a trooper.

The law is you yield.

NC_Native said...

I won't EVER let lane cheaters cut in front of me. Ain't gonna happen Anonymous 3:27. One of the worst places for this is Brookshire Frwy. westbound onto northbound I-77 in the afternoon rush. You know you need to be in the right lane to get onto 77 but you zip around everyone waiting in the exit lane and then muscle your way onto the exit ramp at the last minute and nearly cause an accident. Not in front of me you don't.

Anonymous said...

another semi-related "issue" I have are with arrogant truckers that create their own "buffer" to force other cars to merge. When two trucks will drive side by side and not let anyone pass so when the roads merge 5 miles ahead it is maybe easier. I have no idea. Saw it last month on 26....up a Mtn where trucks cant accelerate easier. It was a joke. Truckers were swerving into lanes to scare the cars that made it by them and their little traffic wall.

Anonymous said...

Looks to me like Mary loses this argument, not only in the court of public opinion but as far as the law is concerned, as well.

John said...

The bottom line is this...

If you cross a lane marking and collide with another vehicle, YOU are at fault... no discussion, no argument, no chance in court.

Subject is closed.

heavenlyday said...

The anonymous post at 3:33 today was exactly correct. The traffic already in the lane has the right-of-way over any traffic that wants to enter the lane. This has been one of the rules of the road since before I started driving 43 years ago. Many drivers today either do not know this or choose to ignore it. I frequently have to remind them of this rule with my vehicle presence and my horn.

John said...

Courtesy is a gift, NOT a right.

Anonymous said...

Almost everybody is missing the real traffic problem here. To cause the least backups at a bottleneck, the flow of traffic through the bottleneck needs to be maximised. To do this, cars need to be closely spaced and moving quickly through the bottleneck.

The inconsiderate ones (and the cause of unnecessarily large backups) are the rubber-neckers and those who take their good old time getting through the bottleneck since they feel like they deserve it since, after all, they have been waiting so long.

Given this, I have no problem whatsoever getting to the front of the line in the empty lane and getting into a gap in the line. The reason for that gap is that the driver who allowed that gap is almost certainly the same inconsiderate person who is going to rubberneck and not move quickly and tightly space through the bottleneck.

Anonymous said...

The issue dissolves into two points of view: considerate vs inconsiderate, rude vs polite, civilized vs uncivilized.

People in their automobiles are able to avoid direct contact with those they are rude to, thus, feeling anonymous, believe their rudeness is not attached to them, so their childish behavior bullies its way past their upbringing.

I see it most often at a 4 way stop I pass through quite often. I always find it amusing to pull out in front of the ones going out of turn to see if they'll hit my beat up old truck.

They've been chicken so far, which to me reflects their true personalities.

Anonymous said...

What Mary is describing is the "zipper" approach to merging two lanes in traffic. It is the norm in Germany where people actually know how to drive.

Anonymous said...

The problem is that 90% of the people in that right lane pulled out of line in the left lane a mile back in the hopes of cutting in front.

There's only two types of people at the front of that right lane with their blinkers on: The ignorant ("Oh, gosh, was this lane ending? I had no idea!"), and the jerks ("I shouldn't have to wait in this jam, I'll just pass everyone and make someone let me in.")

Anonymous said...

First there is not sense in arguing against someone that feels their time is more important that everyone elses. Second, the people that slow down to let someone in do not cause wrecks. The people behind them that are not allowing proper space and are not paying enough attention to realize the car in front of them is slowing down cause the wrecks.

Dave said...

"The reason for that gap is that the driver who allowed that gap is almost certainly the same inconsiderate person who is going to rubberneck and not move quickly and tightly space through the bottleneck."

Did it ever occur to you, Anonymous 10:16, that the gap is there as a defensive measure? It's all too easy to get pushed into the car in front of you if the bonehead behind you isn't paying attention and rear-ends your car. I always leave a slight gap in these situations because I assume that someone like you is behind me. But I don't rubberneck, and I move as quickly as practical past the obstruction.

Anonymous said...

Wow, I am surprised by the opposition to this concept. I never thought about it until I recently moved from Charlotte to DC and saw first hand how this works. Traffic moves so much faster when two lanes are used and alternate cars. Given how bad DC traffic is, I am not surprised that they figured this out. You should give it a try.

Anonymous said...

tibia money tibia gold tibia item runescape money runescape gold tibia money tibia gold runescape gold runescape accounts tibia gold tibia money runescape money runescape gp buy runescape gold tibia gold tibia item buy runescape money runescape gold runescape items tibia money tibia gold

sexy said...