06-19-2008, 12:37 PM
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#11 (permalink)
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Hypermiler
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Well said - distant draft only, for safety. I choose to draft no closer than 3 seconds, and that still gives a 10%+ benefit. Of course, that requires a truck going as slow as I want to, which is rare.
Also, faster traffic from the rear will pass without even a second look at you.
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11-mile commute: 100 mpg - - - Tank: 90.2 mpg / 1191 miles
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06-19-2008, 01:44 PM
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#12 (permalink)
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Master EcoModder
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Quote:
Originally Posted by Who
jamesqf, and I wish it were a lot more rare. I'm familiar with 2 fatalities during a relatively short time period that were caused by lost truck wheels on a local section of freeway (QEW) that I frequently travel.
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I've no doubt that it can and does happen. The question, though, is where the cars were that got hit, relative to the truck that lost the wheel. Were they directly behind (drafting, IOW), or off to one side? As I said, just thinking of how things might bounce around, it seems that directly behind would be safer than behind and off to the side.
Quote:
Your post seems critical of mine. Am I wrong to mention safety considerations?
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Of course not. I'm just questioning the assumption that directly behind is the least safe spot. I think - and I admit it's just an opinion - that taking everything into consideration, in many situations I am in fact safer behind (though not TOO close to) a semi.
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06-19-2008, 01:52 PM
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#13 (permalink)
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Bicycle Junky
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I haven't tried the "surf drafting" yet as most of the highways I traverse are either "trucks stay right except to pass" or are 2 lane only in one direction which creates a complete road block if doing the above.
When I'm on the highway though, I generally can sit about 40 feet behind a truck (well within my opinion of a safe distance (10ft per 10mph, doing 55, close enough). I jump from 36mpg to an incredible 47-50mpg when drafting and most truckers don't seem to mind, I generally try to gauge by whether they are speeding up to give themselves more distance or if they slow down, etc. You can generally tell how they feel by watching how they react when you "engage" on their draft.
Quote:
Originally Posted by Tony Raine
my best "safe drafting" technique so far has been my CB.
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I hava thought about the CB idea, but how do you identify whatever truck you're trying to get a hold of?
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Last edited by NoCO2; 06-19-2008 at 02:51 PM..
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06-19-2008, 02:24 PM
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#14 (permalink)
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Master Novice
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Any draft is a draft, whether you're behind a tractor-trailer or a Honda Fit, although perhaps tailgating Basjoos' Aerocivic would be a capital waste of effort.
A close-coupled tailgater is doing the lead vehicle a small favor by acting as the lead's new tail. Following closely, the tail vehicle gets less nose drag because that's the lead's problem, and the lead gets less tail drag because that's the tail's problem. Be that as it may, when another vehicle gets too close, I back off the throttle until they get fed up and pass. I don't want anyone closer than fifty feet or so, and that's my absolute minimum.
I don't like cuddling up too close behind a rig not because of the potential risk of flying delaminations but because I can't see anything else. Part of being an alert defensive driver is knowing what's going on ahead of me. I don't want to rely on the juggernaut's inertia to act as my buffer zone, that means that in the event of an emergency, I might wind up driving over somebody's mangled body. The truck will probably be what kills them, but still - I weave to avoid flat squirrels, I sure as heck don't want to hit a person, mangled or otherwise.
So dropping back a second or so behind a regular car gives me some palpable results and still allows me a long view down the road. Now, if only I could find a fellow hypermiler that's doing the same pokey 55mph that I'm doing. Seems to me that everyone out there is in one heckuva hurry and that 55mph speed limit is a lower limit, not an upper limit.
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06-11-2009, 07:13 PM
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#15 (permalink)
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EcoModding Apprentice
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I've seen tires break in front of me. Last week I had to head for the ditch as a piece of rubber i'm pretty sure was larger then me flew at me. The transport behind me followed me to the shoulder. I was directly behind the transport but far enough back I had time to react, and get around the flying obstacle.
As for the poster who claimed that 'driving isn't safe anyways': The odds of me dying on the highway in my lifetime is 1:5000. I have a better chance of dying on the road, then dying due to the top five killer dieses including various cancers, heart diesease, and a few others. I'll do anything reasonable to increase those odds in my favor, like maintaining my vehicles safety systems, and driving in the safest manor i can.
And you should too. Every year, people die on the highways for no better reason then that they thought it would never happen to them.
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06-11-2009, 07:24 PM
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#16 (permalink)
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EcoModding Lurker
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I experimented with some close (<1 sec) tractor drafting last month on two separate occasions for over an hour. Safety concerns aside, it's not difficult from a purely technical aspect, but from my tank calculations (no Scanguage), <1 second drafting at 60-65 mph doesn't provide appreciably better mileage--at least on my Taurus--than does cruising at 50 mph. In fact, I suspect the extra heft needed to maintain the draft canceled out the resistance benefits. When you add the safety considerations mentioned in this thread, it doesn't seem worth it. I won't be doing it again. Long drives are much more enjoyable when I'm not constantly matching my speed to that of a vehicle ahead of me.
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06-11-2009, 08:35 PM
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#17 (permalink)
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EcoModding Lurker
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I find that drafting a semi around here (Toronto/Mississauga) is actually safer than you might think. My reasoning goes like this:
1 - Semis always leave a long space between them and the vehicle ahead
2 - Even my crappy car without ABS can break in a shorter distance
So, the space they have ahead provides a steadier speed than vehicles around you because it absorbs the rubber band effect, even when traffic gets more congested. Holding a steady speed and slow breaking of the rig or just working through the gears means that you'll rarely have to use the brake unless traffic comes to a complete halt or the rig engages in an emergency maneuver that involves locking the brakes. Even if the latter happens a smaller vehicle, especially if outfitted with ABS can still avoid a collision if the driver knows what s/he's doing and is paying attention to the road. In fact for this to work the driver must not lose focus and if s/he feels that is happening s/he should break off ASAP and resume normal driving.
Yes, it is dangerous but not absurdly dangerous if you are responsible enough to drive within your limits and the limits imposed by the traffic conditions. You need to use your best judgement to call it off or not even attempt it if there is any doubt about safety. There's a time and place for everything.
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06-11-2009, 08:59 PM
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#18 (permalink)
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Moderate your Moderation.
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You can almost universally contact a trucker by the description of his truck and/or the mile marker/highway you're on.
Almost all trailers have numbers on the back of them, huge, easy to identify. The truck might also have a company name on the side, different from that on the trailer. Check that you can identify the type/brand/make of the truck that's being contacted. Refer to truck numbers (different from trailer numbers). Something will usually catch their attention, or you're on the wrong channel.
Regardless of whether you can see a personal name printed on the truck's door/side/anything, DO NOT use it on public broadcast. You might get run over.
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06-11-2009, 09:58 PM
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#19 (permalink)
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EcoModding Apprentice
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Quote:
Originally Posted by JV-Tuga
I find that drafting a semi around here (Toronto/Mississauga) is actually safer than you might think. My reasoning goes like this:
1 - Semis always leave a long space between them and the vehicle ahead
2 - Even my crappy car without ABS can break in a shorter distance
So, the space they have ahead provides a steadier speed than vehicles around you because it absorbs the rubber band effect, even when traffic gets more congested. Holding a steady speed and slow breaking of the rig or just working through the gears means that you'll rarely have to use the brake unless traffic comes to a complete halt or the rig engages in an emergency maneuver that involves locking the brakes. Even if the latter happens a smaller vehicle, especially if outfitted with ABS can still avoid a collision if the driver knows what s/he's doing and is paying attention to the road. In fact for this to work the driver must not lose focus and if s/he feels that is happening s/he should break off ASAP and resume normal driving.
Yes, it is dangerous but not absurdly dangerous if you are responsible enough to drive within your limits and the limits imposed by the traffic conditions. You need to use your best judgement to call it off or not even attempt it if there is any doubt about safety. There's a time and place for everything.
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That sounds good until the truck your drafting swerves around the accident that kills you.
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06-11-2009, 10:11 PM
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#20 (permalink)
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Moderate your Moderation.
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Quote:
Originally Posted by stevey_frac
That sounds good until the truck your drafting swerves around the accident that kills you.
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That really doesn't deserve attention, but I'm bored....
Semi's CAN'T swerve around something fast enough that a driver (even one seemingly attached to his ass-end) can't react before hitting whatever the truck swerved around.
What that means: Even if you're attached nose to tail with a trucker, and he needs to swerve, the amount of time he'll need to successfully maneuver around an accident or the like will inevitably provide you with "sight time" enough to proceed in the same manner. If it didn't, the driver of the truck would inevitably hit whatever obstacle was in the road.
There is a very distinct appearance to a truck that is swerving, versus one swaying or anything else... any driver who can tail one that closely, would probably have learned to react based on the demeanor of the truck in front of him, as a matter of not being able to see in front, which also says that you wouldn't necessarily need to see the obstacle in order to know it was present and how to avoid it.
There is a given problem with tailgating a truck of that size though - he may not swerve for something that is still large enough to damage your vehicle intensely, like large rocks or medium animals, "gators" (tire treads), and other smaller obstacles. Draft at your own risk.
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