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Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

nautil.us

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Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#2
In the US one of the biggest problems I have experienced is that drivers do not adhere to the international rule of having slow drivers on the right side of the freeway, especially in California.

As a result to this there are more lane splitting episodes (even within the speed limit) in order to finally being able to keep moving at a faster speed because the lane is effectively blocked by other drivers.

In addition to that, occasionally drivers will go faster (emergency, being late, and so on) and those same slow drivers that occupy each one of the 5 lanes at the same time will amplify the lane splitting, ultimately causing temporary traffic jams.

I never really understood why is this - in Europe we automatically merge to the right and always try to keep the leftest lane available for whoever needs to use it.

Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#3
post #2

In the US one of the biggest problems I have experienced is that drivers do not adhere to the international rule of having slow drivers on the right side of the freeway, especially in California. As a result to this there are more lane splitting episodes (even within the speed limit) in order to finally being able to keep moving at a faster speed because the lane is effectively blocked by other drivers. In addition t…

This used to bother me, then I realized that under heavy congestion conditions, you probably get higher overall throughput on the highway if no one tries to keep a lane free.

Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#4
post #2

In the US one of the biggest problems I have experienced is that drivers do not adhere to the international rule of having slow drivers on the right side of the freeway, especially in California. As a result to this there are more lane splitting episodes (even within the speed limit) in order to finally being able to keep moving at a faster speed because the lane is effectively blocked by other drivers. In addition t…

in Pittsburgh, part of the reason is that there are some exit ramps off the left lane. People who are afraid to change lanes get in the left lane and stay there for miles so they don't have to merge to get to the ramp

Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#6
post #2

In the US one of the biggest problems I have experienced is that drivers do not adhere to the international rule of having slow drivers on the right side of the freeway, especially in California. As a result to this there are more lane splitting episodes (even within the speed limit) in order to finally being able to keep moving at a faster speed because the lane is effectively blocked by other drivers. In addition t…

California drivers do tend to not “keep right”, partly because the highway designs that Caltrans uses tend to prefer angled-merge on-ramps rather than parallel acceleration lanes.

Drivers soon learn that the rightmost lane often has congestion due to merging cars arriving at the merge point in groups created by off-highway traffic lights, and then tend to avoid driving in the right-most lane. Metering lights on the on-ramps help reduce the grouping, but the angled merges remain, as does the learned behavior.

Also, many US states post signs: “Keep right except to pass” but California posts “Slower traffic keep right” and since nobody wants to identify as “slower” we do not.

Interstate 5 in the Central Valley is generally two lanes, and semi-trucks and vehicles pulling trailers are limited to 55 mph, and must keep right except to pass. Other traffic has a higher speed limit. When traffic is heavy, nobody leaves the left lane because they are much less likely to find a gap to merge into.

Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#7
post #2

In the US one of the biggest problems I have experienced is that drivers do not adhere to the international rule of having slow drivers on the right side of the freeway, especially in California. As a result to this there are more lane splitting episodes (even within the speed limit) in order to finally being able to keep moving at a faster speed because the lane is effectively blocked by other drivers. In addition t…

in California, at least SoCal, this "rule" has no meaning, as the congestion is at maximum level. there are simply too many cars for fast traffic to even be possible. even during non-rush hour periods the congestion is ridiculous. the only time I've driven comfortably on the highway is after 11pm and before 6am.

Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#8
post #2

In the US one of the biggest problems I have experienced is that drivers do not adhere to the international rule of having slow drivers on the right side of the freeway, especially in California. As a result to this there are more lane splitting episodes (even within the speed limit) in order to finally being able to keep moving at a faster speed because the lane is effectively blocked by other drivers. In addition t…

One of the biggest problems I experience on freeways in the US is that traveling 5 or even 10 mph above the posted speed limit makes you a "slow driver". So even though you might feel that travelling at or above the maximum legal speed limit should give you the right to occupy the "fast" lane someone will prove you wrong by screaming up your ass at 80 mph, 90 mph, or more, flashing their high beams and becoming irate.

Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#9
I've been intrigued by traffic after moving to SoCal from Oklahoma. day after day you will hit pockets of slowness only to find out there was no obstruction.

in the past I read about 'shockwaves' in traffic. one guy changes lanes too fast, which causes multiple lanes to hit their brakes, and then you get the shockwave effect ("Jamiton" in this article) and it lasts a long time. but after doing enough highway driving, I don't think that's the main issue.

my hypothesis is it's simply merging traffic. I've noticed on my daily routes that traffic is always bad where there are a bunch of roads merging, and immediately after all the merges finish, traffic speeds way up. bad drivers aren't causing these shockwaves, it's all the sudden merging. I attribute this to bad planning. "hey, this is a major road and it's going across the highway, it should probably have a merge here."

a lot of people bring up zipper merging - better training of drivers will help a bit, but properly planned highway merging would be much more efficient.

Re: Why a Traffic Flow Suddenly Turns into a Traffic Jam (2013)

#10
post #6
post #2

In the US one of the biggest problems I have experienced is that drivers do not adhere to the international rule of having slow drivers on the right side of the freeway, especially in California. As a result to this there are more lane splitting episodes (even within the speed limit) in order to finally being able to keep moving at a faster speed because the lane is effectively blocked by other drivers. In addition t…

California drivers do tend to not “keep right”, partly because the highway designs that Caltrans uses tend to prefer angled-merge on-ramps rather than parallel acceleration lanes. Drivers soon learn that the rightmost lane often has congestion due to merging cars arriving at the merge point in groups created by off-highway traffic lights, and then tend to avoid driving in the right-most lane. Metering lights on the o…

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