Do you merge sooner, or later?

[RandyT]

The zipper merge works theoretically on paper, if everyone is travelling the same speed but as we all know that doesn't happen. On an Interstate, where the speed limit is 70, you'll have people driving 65, 75, 80, 90, and the Ohio State Patrol posts pictures on average of 3 times a week of a few cars they caught running over 100 mph. Tuesday, they posted a picture of one the caught running 107 mph on I-71.

Several years ago I took an 18 year old army buddy home from Ft Sill to his family home in Nebraska. Was out one night at a party while staying with his parents and was talking to one of his high school friends that was 16 at that time. She was complaining that her dad had sold her car. I asked her why her dad had sold her car and she said that she was late getting home and was going to miss her curfew and her dad clocked her at 102. He was a Nebraska Highway Patrol.

 

[MAX-24-Dean]

Death and injuries to workers.

Construction zones that have used intentional rolling slow downs before a merge is required, have had less loss of lives to construction workers. So the new "use both lanes to merge point" would be my choice. Some contracts are being written this way now.
The thought is if you can keep more traffic in all lanes prior to the merge then everyone has to slow down becasue it creates a bottle neck during peak traffic, slowing everyone. Slower traffic is always safer for workers.
The merge to left sometimes clears the right lane and encourages selfish people to try to get ahead and some try to pass as much traffic as possible by speeding up.

Used to Project Manage roadway utlity projects and traffic signals and with the merge ahead signs we had more near misses and accidents.

If you haven't noticed, we are a lawless society. Not all, but in general some people are more selfish than others and this is when the problems start.

I had to go home once minus a carpool co-worker and tell his wife and then later his kids that there dad was not coming home. He died when a speeder in the right lane (passing traffic in the left lane) lost control of thier vehicle.
The "fines double in construction zones", do not work unless there are officers present wrtting tickets all day and everyday.

 

[Hay Dude]

The zipper works because it minimizes the length of the slowdown. It blocks less intersections and reduces the gaps due to stop and go. If everyone would do it potential road rage would be reduced.

especially if everyone also listens to Kenny G while they are merging.
That also reduces road rage

haha

 

[MossRoad]

If you do anything other than what this sign says, you're the problem.

 

[oosik]

Around here I've never seen that second sign about using both lanes. No matter how it's done - there is always that idiot - racing forward in the right lane. Trying to get ahead of everybody. Jams everything up and slows everything down.

 

[WinterDeere]

The zipper merge works theoretically on paper, if everyone is travelling the same speed but as we all know that doesn't happen.

If the road is operating near capacity upstream of the merge, there will always be a slow-down at the merge, as folks adjust to maintain safe travel distance. Whether you use the 1 car length per 10 mph rule or 5 second rule, or just blindly follow your gut, the distance between you and the car in front of you is somewhat dictated by travel speed.

If you're dropping from 2 lanes to 1, and everyone is doing 60 mph with 6 car length spacing (their own vehicle being the 7th), merging all of that into one lane decreases spacing between vehicles to 2.5 car lengths. Natural tendency will be for those drivers to drop their speed closer to 25 mph, adjusting to this closer spacing.

The zipper merge works great without changing speed, when the roadway is not already operating near capacity, and can handle the higher density created by losing a lane. It also works better than everyone stopping, in the above example of full capacity, but does require speed adjustment.


Looking at roads with some nasty merges, those who remember the older Rt. 309 Expressway into Philly have some stories to tell. When I was back in college and driving that road most days, it supposedly earned top ranking as the most dangerous or deadly road in the USA, although I have no idea how they actually measured that. No on-ramps, and a very busy road with traffic typically moving above 70 mph during rush hour, where you'd have constantly cars pulling into that mess from a dead stop. And getting back to the OP, they put this road under construction for most of the early 2000's, to try to fix some of these issues. So, in addition to the original problem, they filled that F'ing mess of a road with a half dozen temporary construction lane mergers over the course of ten miles. It's a miracle there weren't mass-casualties.

The one most people talk about, as at least having the appearance of a "very scary road", is the infamous Schuylkill Expressway. Pronounced "skew-kull", it has the nickname Shurekill Deathway. There are a lot of smaller accidents on that road everyday, mostly rear-endings due to the way traffic cycles from 0 to 60 mph and then slams back to 0 mph every tenth of a mile, but I honestly don't think it's particularly deadly. It's bark is worse than its bite, I think. It sure does seem to excite some visitors though, they talk about their travels on that road like they've just done the donner pass on foot in February.

 

[newkiotiguy]

If you do anything other than what this sign says, you're the problem.

View attachment 1930070

How people can't understand this is truly unreal. It's the damn law here and people still think they know better and try to block the lane. I don't take that well

 

[Oaktree]

How people can't understand this is truly unreal. It's the damn law here and people still think they know better and try to block the lane. I don't take that well

Whoa dude, chill. Now I don't recall ever having seen one of these signs, and I will admit to being one of those who moves into the "open" lane first opportunity so as to not have to crowd in last minute. Assuming this is illegal in your state, how often is it enforced? If the answer is rarely or never then it pretty much ceases to be a law. It's certainly one that makes no sense to me. No one is "blocking" the lane.

To me blocking a lane is cruising in the passing lane doing the exact same speed as the travel lane, refusing to move over to let others by. Seems to be a very common practice in some states.

 

[RandyT]

To me blocking a lane is cruising in the passing lane doing the exact same speed as the travel lane, refusing to move over to let others by. Seems to be a very common practice in some states.

And is against the law in several states. And some states like IL does make an attempt to enforce the law.

 

[Runner]

I would merge left as soon as I knew I had to and could do it safely and with plenty of room. Then, I would leave plenty of space in front of me and not worry about people "cutting in". It's not like a couple more cars in front is going to cause the end of the world.

If some LEO wants to make a big deal out of that, go for it.

As I've gotten older, I realize that the goal in driving is to get there safely with as few conflicts as necessary. It's just pointless to try to "teach other drivers a lesson" by not letting them in when merging, tailgating, honking, gesturing, yelling or whatever.

It's not worth the fight.

 

[newbury]

I asked her why her dad had sold her car and she said that she was late getting home and was going to miss her curfew and her dad clocked her at 102. He was a Nebraska Highway Patrol.

That brings up one of my wife's favorite driving stories.
Seems that in high school (circa 1965) she lived in Fulton, Ms. and the parties were usually in Tupelo, Ms, about 20 miles away. Connected by one prime rural road. Her father, a Doctor, had a strict curfew. So one night after a ball game she was late getting home and drove a "wee fast". The local constabulary knew the car and her father and her well. So when they clocked the car going like a bat out of Hades across the river bottoms they just let her continue on without stopping her. But they did call her father.
The reports were that the muffler was red when she got home. Her father put the car up on cement blocks for about a month.

Now back to merge -
If I'm driving a larger vehicle, like my dually, or dually plus towing a trailer I get over as soon as I can. With the Ford Escape I'll usually continue to about the merge point and try to slip in. I try to let semi's in in front of me which tends to get people honking at me

 

[dodge man]

I wait until the last possible second, I’ve learned that orange barrel paint buffs right off. I actually merge early and just watch the idiots try to get a couple of cars ahead.

 

[ruffdog]

I would merge left as soon as I knew I had to and could do it safely and with plenty of room. Then, I would leave plenty of space in front of me and not worry about people "cutting in". It's not like a couple more cars in front is going to cause the end of the world.

If some LEO wants to make a big deal out of that, go for it.

As I've gotten older, I realize that the goal in driving is to get there safely with as few conflicts as necessary. It's just pointless to try to "teach other drivers a lesson" by not letting them in when merging, tailgating, honking, gesturing, yelling or whatever.

It's not worth the fight.

^^^Exactly how I look at it too. I just want to get to where I'm going.....safely....for everyone. Less drama is the best goal.

 

[Fixastuff]

When going from 2 lanes to one at capacity the obvious solution is to double the speed not to lower the speed.

One day with all auto driving cars this will be the norm. Cruising at 70mph, construction ahead so let’s merge at 140. An easy time saver with O downside

 

[TractorTYMe]

Mergine lane is a big failure in 'Murica, people zip immediately to the left while they are still slow. Then they get mad when I come up from behind and accelerate up to speed limit and then merge in front of them. I think most drivers has this "I wanna be 1st in line" syndrome?

 

[ericm979]

Yea a lot of people trundle down the on ramp and only consider speeding up when they're actually on the highway/freeway. In Pittsburgh PA they stop at the end of the on ramp to wait for a break in traffic!

When there's a 2>1 merge I try to do what other people are doing. If everyone is merging in early I'll do that, just so I'm not that guy that people are cursing for cutting the line. If people are going to the end and zipper merging I'll do that. I see both done in California. I think zipper merging is better but the other is fine too.

 

[dstig1]

If people merged into the thru lane when they saw the first merge single lane ahead sign then slowed down to 55 (its the law here) then everybody could go thru the construction zone at 55.

Unfortunately that only works when traffic volume is low enough that one lane is sufficient to carry the volume - and it works great in those situations. If both lanes are full at rush hour, it is going to stop no matter when or how you merge as there are just too many cars for the available space. In that case, use both lanes up to the end and you will at least pack more cars into that distance. There is no magic bullet...

 

[Oaktree]

And is against the law in several states. And some states like IL does make an attempt to enforce the law.

I wish more states did this. Practice seems quite rampant in Virginia, at least every time I've been thru there.

 

[MossRoad]

If people merged into the thru lane when they saw the first merge single lane ahead sign then slowed down to 55 (it's the law here) then everybody could go thru the construction zone at 55. There would be no waiting to merge at the last minute, no cutting in line, less stress and less horn honking and road rage. The first merge sign is usually 1/4 to 1/2 mile from the single lane which would allow easy lane change and reduce the bottleneck but too many won't do that because they are in a hurry and would rather pass the smart ones who merged and are doing 55 already.

Unfortunately, an unbeknownst to many, that's just not the way it works.

It's impossible for everyone to go the same speed. And if the first car is going 55, everyone behind that car will be doing less. The more cars, the slower the ones at the back. Then all of a sudden you get surging traffic. fast slow fast slow....

Studies have been done on it. I'm sure most have seen it. You're driving along and traffic comes to a near stop. Then it picks up again. Then stops again. Several times. Then takes off like normal again and you look around and there's nothing that would have caused a traffic jam. No wreck. No lane restrictions. No merging traffic. What just happened?

This explains it pretty well.

 

[MossRoad]

Here's a timelapse of phantom traffic jam.