singularity's Journal: On driving in the middle lane...

[Note: I think I take driving a little more seriously than the average Joe American. One possible career path for me is as a traffic engineer. I think a lot about driving while driving. This weekend I drove about four hours on interstates in Kentucky.]

OK, Kentucky has signs up, some of the best signs on the subject I have seen, that say "Keep Right Except to Pass". On a three lane highway, this means you should stay in the far right lane, not in the center lane.

I was amazed how many cars were just cruising in the middle lanes. Lane discipline is an important part of keeping traffic flowing well. Compare average speed differentials in Europe (the difference between the slowest cars on the road and some of the fastest) and see the huge difference. Then compare fatailty and accident rates. They are about the same, if Europe is not slightly better than us.

One reason? Well, other than the easy "more reasonable speed limits", a lot of it has to do with proper lane discipline. If a car is going to be going 90mph on a rual stretch of American interstate on the same roads as cars going 60mph (a 50% speed difference), people need to be better about lane discipline.

Cars going the slowest, 60mph, should be sitting in the right lane, never moving from there. Cars going faster than that (70mph, for example), would be crusing in the right lane until they come across one of these cars going slower. They check their side view mirrors well, and then pass on the left. As soon as they get past the car(s), they move back to the right. As speeds get higher, a car is going to be spending more times in the middle and far left lanes since they are going to be passing slower traffic all the more quickly. Even a car that is the fastest on the road, however (90mph in our example) should not simply cruise in the far left lane. They should stay as far right as possible except to pass.

Using this method, especially the part about recognizing on-coming cars well and not pulling out in front of them, a three lane highway with moderate traffic could easily handle traffic ranging from 60mph to 90mph.

Try the example again with the cars cruising at 60mph in the middle lane, with the right and left lanes open (along with merging traffic from the right). People complain about weaving. This set-up will cause more weaving and more accidents. The example is left as a mental excercise.

Agreed

[jrockway]

I have some random thoughts/observations about freeways, so I'll post them here.

The drivers on freeways in Illinois (namely 94, 294, 53 and 88) also exhibit this strange behavior. Apparently, the slow traffic ends up in the center, with the ultra-fast (85+mph!) traffic on the left, and ~70mph traffic ends up on the right. Occasionally a person doing 55 in the right lane (like they should!) ends up backing up the freeway for miles. I just don't understand it.

However, we are taught in drivers ed (and def

Re:Also agreed

[rpresser]

When traffic is at 75, the person going 55 and the person going 95 are equally dangerous.

I would disagree that they are equally dangerous. If persons X, Y, and Z are going 55, 75, and 95 respectively, then Y has more time to react to X making a stupid move, than if Z makes a stupid move.

But you're right as far as saying that if all are going at 75, accidents are less likely.

Re:Also agreed

[Sketch]

Here in Florida, the person going 55 is more likely to be over the age of 65 and have a much larger delay in their reaction time. Quite possibly enough to have less time to react at 55 than a younger, more able-bodied person doing 95. ;)

Too bad they don't re-test drivers every 5 or 10 years to make sure they are still capable of driving. (Not that the initial test really requires one to be capable, but that's another complaint entirely...)