Originally Posted By: dnewton3
This entire topic is really a sub-sect of a continuing issue of volumetric flow. Our road systems in North America (particularly the US) have not kept up with traffic volume overall.
Lots of studies are done every year, by State and Fed agencies. They all come to the same general conclusion on this topic; more cars than available space in peak times and areas makes for congestion.
There was a study from CA many years ago (I cannot locate the link right now; I'll keep trying) that conclusively proved that lane-hoppers (people who move from lane-to-lane advancing their position) actually alleviate congestion. The reason this is true is the whole concept to the "weakest link in the chain"; if everyone drove as slowly as the slowest driver, the entire mass would be "slow". Therefore disparity of speed is necessary to allow more cautious drivers their choice, and yet more aggressive drivers their speed as well. The problem comes into play when those groups are forced to interact, based upon one individual usurping the environment of the other. Fast folks cutting people off as they dart off to the right for an exit; slow pokes in the left lane. Etc.
I am separating the emotional topic from the pragmatic, mathematical one. To move volume, it's a combination of area, velocity and density. "Area" is available lanes. "Velocity" is travel speed. "Density" is feet between vehicles. Since the "area" (lanes of traffic) is a fixed value, the most obvious way to increase volume is to speed up. Even if that means lane-hopping around slower folks. Also, shortening distances between vehicles increases volumetric flow as well. It can be safe, or dangerous, depending upon the actions of others. Enter the emotional topic again ... Sure, you can try to create a "safe" distance between you and the person in front of you. And the only thing that will happen is that void will be filled by a lane-hopper. It's the nature of math trying to reconcile the contradiction. Everyone wants to get somewhere, at the rate they want to travel. People who travel "fast" are no more or less culpable than those who go too "slow". But the reality is that faster drivers alleviate congestion by making the "flow" greater.
A sub-sub-topic to the sub-topic is that of merging. Folks from both sides need to work together. Whether it's merging onto a system, or because of lane reduction, it does not matter. As best we can, we need to make space for those who need to merge, but there is also expectation of those merging to match their speed to the flow. I cannot decry loudly enough about people whom lollygag up an onramp, not even meeting the minimum flow speed, all while a pile of folks are stacked up behind them. What happens next is totally predictable; the merging speed falls off, causing the merged lane speed to drop, and then back-up, and then cause lane-darting to avoid the impending rear-ending. Semi-trucks are notorious for this. I realize many of them are loaded heavily and will struggle, but I perceive that many don't even try. I most certainly can recognize a WOT attempt to merge, versus them loafing up the onramp to conserve fuel. Merging is not a time to save fuel; get on the loud pedal and stomp it! Old people are also notorious for this; they merge at near dangerously slow speeds. If the "speed limit" is 55mph and the traffic is going 70mph, then by gosh your posterior better be going 70mph at the top of that ramp to "safely" merge; don't expect others to accommodate your slowness.
It's been my idea for decades that there be varied speed limits on roads, by lane, on limited access area, or high-volume grade-access lanes. Example ...
For a three lane limited access area, the right lane would be 55mph speed controlled. The center lane would be 65mph. The left, 75mph. And the "limit" is not only a max, but also a min as well; if you cannot, or will not, travel at the lane speed, get out of that lane. In urban (high-traffic) areas, it could be posted overhead with LED illuminated signs, and have the posted speed above each lane. The signage would be "live" and adjusted according to congestive norms. But in rural areas on interstates, it would be posted on flat printed signage, with fixed speeds. If you cannot sustain that designated speed, you don't belong on the highway in the first place; hit the surface streets. I have seen old dump trucks and such going 45mph in a 70mph zone! Their dilapidated condition and/or gearing won't let them get up to full speed, but that does not dissuade them from entering traffic and causing a slow-down. That is a major safety issue, and it's not the "fast" people causing the issue.
You can "yabut" this to death if you choose, but the reality is that traffic flow is like a balloon; if you squeeze it in one area, it will bulge out in another. If you cause traffic to accommodate a slower vehicle, it will react with alternate, sometimes dangerous results elsewhere. The "best" methodology is to accommodate the masses at their desired travel speed, and make the exceptions fit into the rule, and not the other way around. This is one example where the needs of the many do outweigh the needs of the few or the one.
Well, a very detailed post and thank you for it, BUT, your density/speed argument only holds in rural areas with free flowing traffic. In dense congested traffic, the aggressive drivers only exacerbate the bottlenecks and forces everybody to crawl along at 3 mph through a bottleneck whereas if everybody drove more smoothly, with less braking, traffic could move through the bottleneck at 20 mph. The traffic flow through a highway is limited to the volume that passes through its biggest bottleneck. It does not matter how fast you travel between bottlenecks, the traffic volume will not increase above the flow through the biggest bottleneck.
Same principles apply to speeding up to a red light, it does not matter whether you arrive at the light ten seconds before it turns green or whether you arrive two seconds before it turns green, you will not get to your destination any quicker by racing up to a red light.
Everybody gets held up when an aggressive driver skids off the road or rearends the vehicle in front.