Speed limit reduction towards cities encourage traffic jams?

[agentsteel53]

Or if you do leave a car length or two, someone takes it as an opportunity to change lanes into that spot for no discernible reason, thus negating your efforts.

that right there is the problem.  especially when it's a large SUV.

if I wanted to diminish my ability to see, I'd have put up the infamous window shade.

[1995hoo]

Or if you do leave a car length or two, someone takes it as an opportunity to change lanes into that spot for no discernible reason, thus negating your efforts.

I wonder how frustrating it would be to drive a car with the "adaptive cruise control" feature where the cruise control automatically adjusts the vehicle's speed to maintain a safe following distance. It seems to me that it would constantly slow you down for precisely the reason you note–people construe any gap at all as a space intended for their use.

Heck, you know the principle of not blocking the box? I've stopped at the stop bar at a green light when I couldn't clear an intersection only to see someone from the other lane cut over in mid-intersection into the space I'd left (thereby blocking the box).

[cpzilliacus]

Heck, you know the principle of not blocking the box? I've stopped at the stop bar at a green light when I couldn't clear an intersection only to see someone from the other lane cut over in mid-intersection into the space I'd left (thereby blocking the box).

That's a classic stunt pulled frequently by people who took driver (mis)education at the "D.C. Drive With an Attitude" school.

And I have never, ever seen a cop in D.C. issue someone a ticket for doing that (I think most MPDC officers don't usually write traffic tickets anyway).

[vdeane]

Indeed, and it always amuses me when you get someone from out of town on the road. All of us will be bombing along at 65 to 70 and then we abruptly slow to between 45 and 50. The non-local drivers usually get pissed, start trying to change lanes, weaving back and forth to show displeasure, etc......if you're not a local driver, and you see that all the local drivers abruptly reduced their speed, wouldn't you think there's probably a good reason why they're doing it?

I have seen enough local drivers acting in ignorance of conditions in their area to not assume that is the case.  The example that comes to mind is US 11 in Canton, NY.  In the "downtown" part of the village and the residential area to the east, the speed limit is 30.  East of that area, going by SLU and the hospital, the speed limit is 40.  Because of the idiot locals, nobody can drive these speeds, even though it's safe and legal to do so.  The 40 mph section typically moves between 20 and 30; the 30 mph section often moves between 5 and 10.  Since the primary demographic in the north country is old men, abnormally slow driving is the norm for locals.  The other example I know of is a rail crossing in Sidney, NY; it's perfectly safe to drive it at full speed, but many people feel the need to practically come to a full stop before it.

if we have proven that the entire segment can handle 45 steady flow, and the first half of the segment can handle 65 steady flow - why have the stop/go section at all?  how can we get people to slow down from 65 to 45, as opposed to a dead stop?

By not having traffic stopped in front of those people

Traffic jams are complicated things. You can't just clear them up by saying "OK everybody, go 45 now".

In countries like India where defensive driving is unheard of (the drivers literally pay no attention to anyone except the car immediately in front of them), I've heard that bumper-to-bumper traffic often does move at extremely fast speeds.

[kphoger]

In countries like India where defensive driving is unheard of (the drivers literally pay no attention to anyone except the car immediately in front of them), I've heard that bumper-to-bumper traffic often does move at extremely fast speeds.

Also Los Angeles.  70 mph with three feet between you and the next guy.  Until traffic hits a dead stop, that is, and you do 3 mph for an hour.....  It's been a while since I was there, maybe I remember it wrong....

[agentsteel53]

Also Los Angeles.  70 mph with three feet between you and the next guy. 

I've never seen that happen on a continual basis.  6-10 feet is not unheard of, but 3 is fairly pathological.

[kphoger]

Also Los Angeles.  70 mph with three feet between you and the next guy. 

I've never seen that happen on a continual basis.  6-10 feet is not unheard of, but 3 is fairly pathological.

Fair enough.  The fact that our driver was legally blind in one eye might have skewed my memory of the truth.

[Crazy Volvo Guy]

I wonder how frustrating it would be to drive a car with the "adaptive cruise control" feature where the cruise control automatically adjusts the vehicle's speed to maintain a safe following distance. It seems to me that it would constantly slow you down for precisely the reason you note—people construe any gap at all as a space intended for their use.

The truck has adaptive cruise and emergency auto-brake.  A couple times people have cut so close in front of me that the auto-brake engaged (briefly, until I put my foot on the throttle to override it and back off gently as I usually have some [insert choice words here] tailgating me for no reason).  That'll wake you up.

And on this subject, while I have your attention:

If you leave less than 150 feet in front of a truck before you cut in after passing, you are entirely too close.  Preferably you should leave 250-300 feet.  And please, don't tailgate us to save fuel.  That's a good way to end up under the ICC bar if we do have to panic brake for some reason (I will NOT hit a person on foot, for instance, under any circumstances, unless it is absolutely unavoidable i.e. panic braking will not help - but I will still panic brake regardless.) Ending up under the ICC bar will not go well for you.

And yes, I know "plenty of truck drivers tailgate" - trust me, they do it to me too.  I don't like it, and I'm definitely not one of them.

[Brandon]

By not having traffic stopped in front of those people

Traffic jams are complicated things. You can't just clear them up by saying "OK everybody, go 45 now".

the question is, what gets them stopped?  "person N is stopped because person N-1 is stopped" is great inductive reasoning, until you reach the base case - there is, by definition, someone who is at the front who is stopped, even though the person in front of him did not stop.

this person must be found, and shot.

Most agreed.  Around Chicago the one asshole who slams on his brakes makes the other folks create a brake light wave down the flipping freeway.  It doesn't help matters that people in the other lanes see the asshole brake then proceed to hit their own brakes.  This causes the brake light wave effect.  Flipping stupid morons.