The light is kind of a red herring - the optimal way to merge is to use the zipper method, and use two lanes as long as possible. Pre-emptively going to one lane lengthens the stretch of road that is half capacity. If a single lane road can handle 3,000 cars a day, and a two lane road can handle 6,000, every inch of road that is single lane is limiting traffic and exacerbating the problem.

Pennsylvania has recognized this and actually has developed something called the late-merge control method. This helps manage traffic by telling motorists when to merge - ie late - to promote more efficient merging and traffic speed. Its slowly being adopted by other state DOTs, but motorists need education on how to merge still.

 

Ok, here's a real life example. I am depicting a person trying to get from the right side of the photo to the left side of the photo.

This intersection backs up..there is another redlight less than 100 yards downstream to the left of the photo (just off the photo).

So coming from right to left, you can see the red lane vanishes after the light. There ain't much room after the light before the merge, and the 'merge' lane actually is ported into a forced right turn after the main intersection...it's purpose.

Some folks use this lane to get the jump on folks waiting in line. This definitely slows this intersection AND it slows the folks that actually want to use the lane as designed to take a right turn as the lane forces them to do at the end, because they are stuck waiting for the gap runners to bully their way into traffic. This in turn slows the bullies behind them because they are now at a slower speed and will inject this slowness into the merged lane when forcing their way in. It slows the whole show.

 

No, it's not. It's an important factor into the overall behavior of the traffic in this area. Ruprecht has already described why it's beneficial to perform the merge before the light (in the case where the light is red). If the light was always green, then it would not play a role in the overall process... but that's not the case.

It's true that the best merge algorithm is the zipper method. It's also true that you can get more people through a light if they're using both lanes. However, at the point that two lanes become one, then all traffic will have to slow to half speed to perform the merge assuming they maintain equal spacing between vehicles before & after the merge (they'll actually be travelling at less than half speed during the procedure due to human interaction). If this "slow-down" propagates all the way back to the light, then it is no longer beneficial to use both lanes since everyone is now travelling at less than half-speed through the light. In this case, it would've been better for everyone to merge into one lane before the light (while the light was red). That way, when the light turns green, then everyone can travel at full speed through the light and that will provide an overall higher capacity at this junction.

 

The only thing the light effects is traffic flow. It bunches up traffic so you have heavy flow, where late merging is most optimal. Like I said, you can merge early, but its not optimal or fast, as you know as you watch other cars pass you by. Now Rue is talking about holding up people trying to go right up the road, and that's not the issue. The issue is the best way to merge, and there being a light nearby, the best way to get cars through an intersection.

 

[QUOTE=Saki GT,Mar 21 2008, 10:19 AM] Now Rue is talking about holding up people trying to go right up the road, and that's not the issue.

 

Well, like I said, I'm not here to argue with how you want to merge. I'll take the fastest way through, and for me, thats the empty lane, with a late merge. Just don't hate on me because I'm not doing what you think is correct.

I don't look at this like a winner-loser situation. If you have 40 cars in a line to go through an intersection, and the light is timed so that only 15 can get through, you'd get 30 through using two lanes, and 15 through using one lane. Speed of merging and how happy everyone is can come later, after they're through the intersection. You'd think people would be happier not having to wait at a light two or three cycles.

Thinking of evrything we do on the road as a competition is part of the reason American drivers suck imo. This competitive "I can't let you in or I'll lose" thinking leads to lots of anger and accidents, and slows traffic. I typically see this in the suburban areas where people don't know how to handle traffic.

 

Naw, this is great discussion. I am always fascinated by what makes folks do the things they do. And every now and again I do learn something from it.

 

some of this depends on the area of the country you live in. mild driving in DC is fanatical road rage here in salt lake city.

i think i agree with both of you in a way on the hypothetical 2 mile traffic lane with a merge ahead in the distance.

i rarely will wait for the 2 mile line when i can roll along and merge late unless i'm moping along the road (usually in my wifes car).

but i must add that this assumes i won't have to cut someone off to merge. if that's the case, i'll wait in line. theres no sense in extending a bottleneck, IMO, but if i am cutting people off, i'm pissing off nice people AND slowing traffic for my own gain, and IMO the negatives for the local population far outweigh the direct positive effects to me (getting in faster). that's not something i intentionally do without an unusually good reason.

 

Good grief, the things people complain about. If you guys ever come down to the Caribbean, don't ever rent a car and drive - you all won't make it through the first day. Cut-offs, no merge sense, using the shoulders as a lane, stopping on a highway to let someone out etc. etc. etc. Those are the problems you deal with as a matter of fact, and a lot worse. And then these don't even compare to what's going on in South America, Mexico etc.

Back to the Power question, is it more HP you all want or more torque? The S has lots of HP but little engine torque. That power will get you to some scary speeds if you have the space for it. If you want to fill gaps in the traffic and prevent "rogue mergers" from doing there thing, you will need a lot more torque, or a lot less weight. Go ask the Evo guys - that is how they get kicks in their cars every day. They get to feel the straight line acceleration that we don't because of lack of engine torque/too heavy.

Our smiles come from elsewhere on the performance chart, but just as sweet from where I sit.

Enjoy your higher HP. I will enjoy my stocker!

 

I am well familiar with Carib driving habits and Carib beer too!

I for one hope we don't encourage more of the habits seen down there. It is exactly as you describe and worse.

HP or torque (whichever it takes), I want the power to keep the other guy from taking my spot in line. And...if we all drove with that in mind, the road bullies strategy would fail (they'd be stranded with their blinkers on) and eventually they would cease this behavior and form an orderly queue with a net result of more volume through the light.