Is this the right freeway driving strategy?

burritos · Feb 23, 2006

Originally posted by donee@Feb 22 2006, 09:40 PM
Hi Burrito,

Â Â Â I disagree with your method. At 1/2 mile following distance, there is no way to judge your closing/opening rate (at least without a laser rangefinder). Thus, traffic may run away from you, which means cars in your lane would and could move right, then come back around in front. One can see the people moving around are trying to maximising the road resource but it does at the expense of the center lane resource. Of course I see this on regular basis in Chicagoland. I move around too, about once a month. On the road I drive, the people going slow in the left lane are the ones that are staying on the road for 20 miles, and are timing an average to a delay down at the end of that 20 miles. This is faulty logic, as their actions and the actions of others in response are changing the amount of time they will be in the delay. They may think that more cars are getting through the delay while they proceed slowly to it, but more cars are also filling into the delay ahead of them too. In the end, they are in stop ang go the for more time, I hazard to guess. Not only due cars moving ahead of them already on the road, but also from cars entering the highway ahead of them and holding back cars that would leave the highway sooner.Â The road network is a system, not just a pipe.

In my drive, behind the slow left lane drivers, 1/2 the traffic is getting off at 5 or 10 miles (including me), before the delay at 20 miles. I have seen see a 3/4 mile stretch of empty left lane pavement, and no way for the lead car in that lane to judge the average to the next exit, and nobody moving left into it. They are judging not the present situation, only remembering the past. Now, that is fine, if there were nobody else on the road, but delaying somebody based on ones personal imperative shows a lack of empathy (and may be percieved as saddism by the one being delayed). The road I exit off too has a remarkable consistent evening loading characteristic. If I am not on it by 4:59 pm, the ten miles I drive on it will take nearly double the time. There have been many times I have seen it flowing at 65 from the top of the 1/2 mile long ramp at 4:59, only to be in dead stopped traffic at the bottom at 5:01 !

Â Â Â Additionally, I believe your method is fuel consumption inefficient for your car, which has an Otto cycle engine (not an Atkinson with good partial throttle efficiency). Otto Engine efficiency peaks at about 40 % power and 75 % torque. Not accellerating when there is room (1/4 mile or more following distance) wastes gas. The trick then is to accellerate only enough and at the right time to come coasting up the cars that are braking, just as they begin to accellerate again. One way to do this is to not accellerate, until the the cars ahead of you are just short of their peak speed. As you accellerate, you can judge if the peak is true to the cycle or different, and modulate the acceleration time appropriately. Its typical that the accelleration then is only 5 to 10 seconds.Â It also takes a few cycles of the start and stop to gauge the cycle period. Once in anti-phase, braking is rare - your goal. This anti-phase technigue I found much more effective in my SL2. With whichÂ routinely got 30 mpg or more even during days when it was below freezing in the morning, and above in the afternoon and the traffic was 0 to 70 mph in the waves.Â If one does not follow close enough to make the judgements for this anti-phase pulse and glide, one will waste the public resource and end up with 1/2 mile or more empty lane , or dangerous traffic.

Â I think the rolling road block effect is the biggest problem with the technique esposed on http://amasci.com/amateur/traffic/traffic1.html, which is apparently close to your driving style.Â The examples given of the method rely on a long range sightline to the delay, which is not the norm around here. A line of cars all at the same speed is fine on a one-lane road that will eventually come to a traffic interferance that one can see off down the side of a mountain is fine. This just does not describe a modern super highway in the midwest or most metro areas with a belt-way layout. Mr Beatty apparently agrees with this too - on the websiteÂ his comments: "On the other hand, the situation is not so simple if lots of extra traffic is entering from numerous on-ramps. The "rolling barrier" can't affect these extra inputs, and if nearly all of the traffic is from on-ramps, then the "rolling barrier" idea would be worthless. In that case it can only control the main highway and not all the on-ramps".

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I think may have misunderstood me. When I say I look ahead 1/2 mi ahead, I'm not saying that the car in front of me is 1/2 mi ahead, I'm saying that if I see braking the traffic 1/2 mi ahead of me, then I won't accelerate. I notice that people right in front of me will speed up only to brake. I'll coast to their back. Usually they will be 5-6 car lengths ahead. Now note, this is when average traffic speeds are 30 mph or less(basically stop and go). When traffic speed are more than this, then it's no longer stop and go and there no need to coast as people aren't really braking, thus I no longer apply this strategy.

In stop and go traffic, are you advising that you speed up to stopped traffic ahead of you? And then brake suddenly?

Also if you think this method is inefficient how do you explain IsrAmeriPrius's post?

"Don't know about your experiences, but the other day it took me an hour and twenty minutes to drive on the southbound I405 from the US101 to the Howard Hughes Parkway, a distance of about fifteen miles. My nerves were frayed, but the car got well in excess of 80 MPG in that segment (most bars showed 99 MPG). I had about 100 miles on that tank, at the time, and the average MPG climbed more than 10% in those fifteen miles from the low fifties to almost sixty."

SpaceCadet · Feb 24, 2006

Originally posted by gschoen@Feb 21 2006, 09:20 PM
For the type of roadway Tony described, non highway with turning lane, driving in the left lane is entirely appropriate, whether you're car or truck, slow or fast.Â The "slower traffic keep right" rule is only applicable on controlled access highways, not local roads.

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Actually, in Michigan the law is the exact oppostie. On ANY road with only two lanes in one direction, you are REQUIRED to use the left lane ONLY for passing. On any roadway with three or more lanes moving in the same direction (most expressways in Urban Michigan) the above does not apply. Although you could still be sited for "obstructing traffic."

http://www.legislature.mi.gov/(vlohin3xkdt...ame=mcl-257-634

andyprius · Feb 27, 2006

Originally posted by TonyPSchaefer@Feb 21 2006, 01:40 PM
I can appreciate your opposing viewpoint because I see it every day.Â I maintain the following distance and I coast to the back of the car stopped in front of me and if I time it just right, the car in front of me goes again as I'm less than twenty feet behind them.Â And even then, do I punch the gas? No.Â Does the guy behind me want me to?Â Oh Hell yeah!

I've had a few grenades thrown my way for what I'm about to say, and it might happen again, but it's okay because my monitor's wearing kevlar.
My Prius has moved me into the left lane and I don't want to leave.Â In my daily commute, the VAST majority is two lanes in each direction with a turn lane inbetween.Â If I drive the whole of the 20 miles in the right lane, cars stop to turn right and jump out in front of me or the car in front of me.Â In either case, I have to slam on my brakes only to rapidly accelerate again.Â On the other hand, I maintain a nice leisurely pace in the left lane and when people need to turn left they exit the flow of traffic.Â Now, the car behind me who wants to drive 65MPH in the 45MPH zone gets angry with me even though the rest of the traffic is moving at 55MPH.

So you see, in my case, I maintain the speed of the cars around me, do it in the left lane as much as possible, and maintain a safe following distance and using my brakes as little as possible.Â Some agree, some disagree, but for me, it works.

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The sad truth is we are driving like maniacs in this country now and we used to be the best. In CA the tractor trailers are limited to 55, they do 65. Other traffic is limited to 65, they to 85. Trucks are constantly falling over on their side on entrances and exits of freeways. This shows a total disregard of safety or common sense. I drive 60 in the right lane and I"m always in somebodys way, because they want to pass and don't care if they pass left or right, (unfortunately, legal in CA) On surface streets it's even worse, people ducking in and out of traffic to stop at starbucks just before you. OR in a hurry to get to work, that always kills me. Some drivers entering the freeway are totally unaware that they are supposed to yield right of way. So, you can't win no matter how safe you drive, you are always going to be in somebodys way, then they give you the finger for simply existing. You really have no right to exist on the same roadway with them, how dare you???

gschoen · Feb 27, 2006

Originally posted by SpaceCadet@Feb 24 2006, 03:58 PM
Actually, in Michigan the law is the exact oppostie.Â On ANY road with only two lanes in one direction, you are REQUIRED to use the left lane ONLY for passing.Â On any roadway with three or more lanes moving in the same direction (most expressways in Urban Michigan) the above does not apply.Â Although you could still be sited for "obstructing traffic."

http://www.legislature.mi.gov/(vlohin3xkdt...ame=mcl-257-634

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Actually, in Illinois (where both Tony & I live) the law is exacty as I said.

"Effective January 2004, when driving on an interstate highway or full access controlled freeway, a person may not drive in the left lane, except when passing another vehicle. Exceptions include when no other vehicle is directly behind the vehicle being driven in the left lane, when traffic conditions/congestion make it impractical to drive in the right lane, when weather conditions make it necessary to use the left lane, when there is an obstruction or hazard in the right lane, or when the driver is changing lanes to yield to emergency or construction vehicles."
http://www.cyberdriveillinois.com/publicat.../rr_chap03.html

According to that, the rule about keeping right on full access controlled freeway has only been in effect in Illinois since Jan. 2004.

Is this the right freeway driving strategy?

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Is this the right freeway driving strategy?

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