I think it is a mistake to combine the two cases of "either merging or taking a turn".
If there is an upcoming turn and you can only turn from the inside lane and that lane backs up because, say, there is a light after the turn, then I think late merging can be anti-social and end up slower for everyone. A person who continues on in the through-lane eventually reaches the turn since no slots can open up while cars are stopped waiting for the light to change. He does not want to go past his turn so he stops to wait for a slot to open when the light turns. Now through traffic in the outside lane starts backing up so that not only are people who do not plan to take the turn unduely delayed, so are even the people who are going to take the turn since they are now stuck behind the non-turmers. The net result is that the traffic light now becomes a bottleneck for everyone. When people merge early, the bandwidth of the turn is used efficiently and reaches an equilibrium of some stable queue length before the turn, but when even a small number of people wait too long to merge then fewer people are able to make it through the light on each cycle and so the delay is longer for all groups (early mergers, late mergers, and especially through-drivers). This is a common case in NYC, and famously happens at the turnoff from the FDR drive to the Brooklyn Bridge.
A proper Übermensch does not obey (and cite) bureaucrats in midwestern departments of transportation. The Übermensch takes option 3: the otherwise closed lane lesser mortals fear to tread upon. Otherwise, why not go ahead and put on an N95 mask in the car?
The social cohesion and trust of said ethnically-similar states may allow for zippering but...lol I can't keep this up. Great article, your blog is the best
If I see an opening when there is lots of traffic I will merge earlier. I perceive it as safer than continuing to travel at a high speed in hopes someone will let me in. If I trusted other drivers to obey the rules of the road, I would late merge. But many other drivers are incompetent, negligent, or both. Waiting 10 extra seconds in traffic is worth even a minuscule reduction in the probability of an accident. Getting in an accident is orders of magnitude worse than waiting an extra 10 seconds in traffic; the EV calculation is just not there to late merge if it increases your odds of a crash by even .001%. To expose oneself to risk that does not have a proportional reward is not courageous; it is reckless.
(1) I am a Professor that studies fluid flow (and traffic flow). The flow in the single lane goes the speed it goes. Anything that happens before that single lane makes *absolutely* no difference to the number of cars exiting a merger per minute. Zipper is not better for the collective. Nor is it better for me, so please pipe down and leave my open lane - open.
(2) The only way to improve the merge is for the people in the single lane to drive twice as fast (or at least somewhat faster). If they do that, then one lane can carry two lanes worth of cars. This is what molecules do and why if you force a merge at the end of a hose the water comes out faster. Of course, human drivers do the opposite of what they should do, so they are objectively and provably dumber than water.
I am historically a late merger myself because it always seemed right to me, but I know most people find it very rude. As I get older, I am more wearied by the negative interactions that sometimes occur with people when I am trying to merge late and I sometimes consider merging early simply to avoid these. Also, the extra twisting and turning required isn’t as easy for me as it used to be. So, one day soon, I might find myself to be an early merger as well. So, enjoy merging late while it lasts for you. One day you might wake up and find yourself to be one of those people.
Would someone rather lose 2 min by merging early, and sit back and not having to stress anymore … or gain the 2 min, and now have to worry about someone letting them in, and executing without bumping someone?
Obviously this is going to depend a lot on things like whether you’re running late, risk-aversion, and driving competence.
But most people seem to prefer slower and chiller. It’s totally rational.
It is true that using the second lane until the end increases flow to the entry point of the single lane. However, this is unrelated to the overall throughput since throughput is limited by the single lane flow. Your action can never increase the overall flow, your gain is therefore the loss of the early mergers: your jumping the queue for your own gain. Not polite.
In addition, a late merge will inevitably create hazards. Even if you're a perfect driver, which is not very likely, you have to interact with people like me that might be pissed off you jumped the queue, people that have very little skill driving a car, people that get nervous from this aggressive maneuvers, or just not paying attention. Not only can this disruption cause a gap in the front that cannot be (legally) made up, breaking in a queue can get amplified and cause accidents behind you.
So I think your strategy to jump the queue reduces the average flow for everybody and increases the hazards. So I tend to graciously allow people to merge in front of me early on but at the end I take advantage that my car is really old.
Your third category is motivated by shame or stigma - hence why they're conformist not cowardly. But you posit they all could - and believe they could - merge later if they were willing to stand out.
That's well and good but misses an important group - the genuinely cowardly. You're obviously a skilled driver, or believe so, including when confronting or relying on other drivers to execute a maneuver. That's not an uncommon sentiment.
But it's also not universal, at all! In my experience at least, lots of folks do not know what they're doing to merge on a highway. Or, they are afraid they don't know, or it won't work or something will go wrong in this instance.
Plus, it can be genuinely terrifying, or at least unnerving, to watch the end of a lane approaching as you travel a high speed, and see no ready way to merge. The prospect terrifies many people - at worst they crash head on to their demise, at best they broadside the car next to them and chaos and sorry follow.
This group, the cowardly, prefer to avoid that possibility (if not casualties, at least the hassle of having to squeeze in and not screw up after their first plan fails). They're real and not scarce in number, and your taxonomy is incomplete, and its explanatory power diluted, by your omission.
Another reason is that there can be risk in waiting too long, getting frozen out of the merge.
For example. I have an north exit nearby, followed in a 1/4 mile by a south exit which generally has a longer backup. If you wait too long to get to the right for the north exit, you can get stuck on the wrong side of the backup of cars waiting for the south exit.
Generally speaking, I completely agree with the point of your post. Similar reasoning holds for following cars pretty closely. This actually speeds up overall traffic quite a lot.
I'm confused as to how any behavior *before* the bottleneck can change the speed with which cars pass *through* the bottleneck. If the single lane can admit 0.5 cars per second and the highway is transporting 2 cars per second, traffic is going to back up regardless of where people merge.
I do see how having that backed-up traffic occupy more road space is beneficial, since that means it won't extend back as far and won't interfere with as much cross traffic. But unless zipper merging somehow increases the speed at which cars drive once they're in the single lane (which is very plausible, I just don't get exactly why it would happen), it can't speed up the average travel time of people in the jam to zipper merge.
What am I missing here?
Also, I tend to merge early because I'm very safety-conscious and it's dangerous to try to force myself into another lane of traffic that doesn't want to let me in at the last minute. The earlier I start trying to merge, the more likely it is that I'll find someone who lets me in before I have to slow down to avoid running into the traffic cones.
I think it is a mistake to combine the two cases of "either merging or taking a turn".
If there is an upcoming turn and you can only turn from the inside lane and that lane backs up because, say, there is a light after the turn, then I think late merging can be anti-social and end up slower for everyone. A person who continues on in the through-lane eventually reaches the turn since no slots can open up while cars are stopped waiting for the light to change. He does not want to go past his turn so he stops to wait for a slot to open when the light turns. Now through traffic in the outside lane starts backing up so that not only are people who do not plan to take the turn unduely delayed, so are even the people who are going to take the turn since they are now stuck behind the non-turmers. The net result is that the traffic light now becomes a bottleneck for everyone. When people merge early, the bandwidth of the turn is used efficiently and reaches an equilibrium of some stable queue length before the turn, but when even a small number of people wait too long to merge then fewer people are able to make it through the light on each cycle and so the delay is longer for all groups (early mergers, late mergers, and especially through-drivers). This is a common case in NYC, and famously happens at the turnoff from the FDR drive to the Brooklyn Bridge.
A proper Übermensch does not obey (and cite) bureaucrats in midwestern departments of transportation. The Übermensch takes option 3: the otherwise closed lane lesser mortals fear to tread upon. Otherwise, why not go ahead and put on an N95 mask in the car?
The social cohesion and trust of said ethnically-similar states may allow for zippering but...lol I can't keep this up. Great article, your blog is the best
it's like those people who line up to board the plane when it starts boarding. Why?
the overman stays seated and waits for the line to clear
the overman boards last
late mergers are ASSHOLES!!!!
If I see an opening when there is lots of traffic I will merge earlier. I perceive it as safer than continuing to travel at a high speed in hopes someone will let me in. If I trusted other drivers to obey the rules of the road, I would late merge. But many other drivers are incompetent, negligent, or both. Waiting 10 extra seconds in traffic is worth even a minuscule reduction in the probability of an accident. Getting in an accident is orders of magnitude worse than waiting an extra 10 seconds in traffic; the EV calculation is just not there to late merge if it increases your odds of a crash by even .001%. To expose oneself to risk that does not have a proportional reward is not courageous; it is reckless.
I love this blog
(1) I am a Professor that studies fluid flow (and traffic flow). The flow in the single lane goes the speed it goes. Anything that happens before that single lane makes *absolutely* no difference to the number of cars exiting a merger per minute. Zipper is not better for the collective. Nor is it better for me, so please pipe down and leave my open lane - open.
(2) The only way to improve the merge is for the people in the single lane to drive twice as fast (or at least somewhat faster). If they do that, then one lane can carry two lanes worth of cars. This is what molecules do and why if you force a merge at the end of a hose the water comes out faster. Of course, human drivers do the opposite of what they should do, so they are objectively and provably dumber than water.
Also it's funny that you think misanthropy *doesn't* drive many forms of leftism.
I am historically a late merger myself because it always seemed right to me, but I know most people find it very rude. As I get older, I am more wearied by the negative interactions that sometimes occur with people when I am trying to merge late and I sometimes consider merging early simply to avoid these. Also, the extra twisting and turning required isn’t as easy for me as it used to be. So, one day soon, I might find myself to be an early merger as well. So, enjoy merging late while it lasts for you. One day you might wake up and find yourself to be one of those people.
You missed the main reason: safety and stress.
Would someone rather lose 2 min by merging early, and sit back and not having to stress anymore … or gain the 2 min, and now have to worry about someone letting them in, and executing without bumping someone?
Obviously this is going to depend a lot on things like whether you’re running late, risk-aversion, and driving competence.
But most people seem to prefer slower and chiller. It’s totally rational.
I am not sure the logic is in any way sound.
It is true that using the second lane until the end increases flow to the entry point of the single lane. However, this is unrelated to the overall throughput since throughput is limited by the single lane flow. Your action can never increase the overall flow, your gain is therefore the loss of the early mergers: your jumping the queue for your own gain. Not polite.
In addition, a late merge will inevitably create hazards. Even if you're a perfect driver, which is not very likely, you have to interact with people like me that might be pissed off you jumped the queue, people that have very little skill driving a car, people that get nervous from this aggressive maneuvers, or just not paying attention. Not only can this disruption cause a gap in the front that cannot be (legally) made up, breaking in a queue can get amplified and cause accidents behind you.
So I think your strategy to jump the queue reduces the average flow for everybody and increases the hazards. So I tend to graciously allow people to merge in front of me early on but at the end I take advantage that my car is really old.
You miss a category, no?
Your third category is motivated by shame or stigma - hence why they're conformist not cowardly. But you posit they all could - and believe they could - merge later if they were willing to stand out.
That's well and good but misses an important group - the genuinely cowardly. You're obviously a skilled driver, or believe so, including when confronting or relying on other drivers to execute a maneuver. That's not an uncommon sentiment.
But it's also not universal, at all! In my experience at least, lots of folks do not know what they're doing to merge on a highway. Or, they are afraid they don't know, or it won't work or something will go wrong in this instance.
Plus, it can be genuinely terrifying, or at least unnerving, to watch the end of a lane approaching as you travel a high speed, and see no ready way to merge. The prospect terrifies many people - at worst they crash head on to their demise, at best they broadside the car next to them and chaos and sorry follow.
This group, the cowardly, prefer to avoid that possibility (if not casualties, at least the hassle of having to squeeze in and not screw up after their first plan fails). They're real and not scarce in number, and your taxonomy is incomplete, and its explanatory power diluted, by your omission.
Another reason is that there can be risk in waiting too long, getting frozen out of the merge.
For example. I have an north exit nearby, followed in a 1/4 mile by a south exit which generally has a longer backup. If you wait too long to get to the right for the north exit, you can get stuck on the wrong side of the backup of cars waiting for the south exit.
Generally speaking, I completely agree with the point of your post. Similar reasoning holds for following cars pretty closely. This actually speeds up overall traffic quite a lot.
This is a slippery slope to full on emergency-lane shoulder-cutting through traffic, and it will be a cold day in hell before I let anyone do that.
Many people (I until not long ago) think that last minute merging IS anti social (deadweight loss).
I'm confused as to how any behavior *before* the bottleneck can change the speed with which cars pass *through* the bottleneck. If the single lane can admit 0.5 cars per second and the highway is transporting 2 cars per second, traffic is going to back up regardless of where people merge.
I do see how having that backed-up traffic occupy more road space is beneficial, since that means it won't extend back as far and won't interfere with as much cross traffic. But unless zipper merging somehow increases the speed at which cars drive once they're in the single lane (which is very plausible, I just don't get exactly why it would happen), it can't speed up the average travel time of people in the jam to zipper merge.
What am I missing here?
Also, I tend to merge early because I'm very safety-conscious and it's dangerous to try to force myself into another lane of traffic that doesn't want to let me in at the last minute. The earlier I start trying to merge, the more likely it is that I'll find someone who lets me in before I have to slow down to avoid running into the traffic cones.