So, I recently took a road trip from Chicago to central Florida and back. Because my return trip wasn't quite as urgent as the trip down, I decided to set my cruise control at a more "efficient" setting. It's interesting to view the world at 63 MPH on a 70 MPH highway...
SC) Years ago I spent some time looking for "real" data about highway speeds and fuel economy. I found some official documentation (I think out of Canada) that suggested that most cars don't get better mileage above 55 MPH and "SemiTrucks" have a turning point around 45 MPH. Obviously head wind/ tail wind and gearing etc have impact. During this trip my co-pilot found this interesting blog post from the makers of the cell phone app "automatic". https://blog.automatic.com/the-cost-of-speeding-save-a-little-time-spend-a-lot-of-money-5e8129899fec
Unless I'm reading it incorrectly, their data suggests that the difference between driving 55 and 70 is a 50% loss of fuel efficiency. This was for one specific model of car. And I assume that driving "aggressively" is part of that difference (those that drive 70 or more on the highway probably drive differently at stop lights too) but it's an astounding number.
On a lightning trip to Florida, my BMW ’99 528it made 30mph at 75 and 80mph over the entire 1,200 mile distance - are you (the links) suggesting the car could get 60mpg at 55? 60*0.5= 30? Did I get that wrong? Even 35mpg is unattainable in that car. Maybe a flat road, no turns at altitude and overinflated tires.
E) I'm becoming more anxious for self driving cars. The biggest reason is to avoid the crazies on the road. But this fuel economy thing also has me hoping that OTR speeds will drop when we take the emotional/needy/illogical pilot out of the driver's seat.
It will be a long time before a large enough pool of driverless cars on the road to make any difference, providing the person does not opt to take the controls. Even longer for OTR speeds will drop legislatively. On the bright side, following distance will become more realistic, and unless severely underpowered, might be able to hold speed going up a moderate hill.
F) To anyone who is offended that I would choose to drive less than the speed limit, I am truly sorry. Although I don't believe that the worst thing you can do on the road is drive a little slower, I do recognize that it can contribute to dangerous roadway situations. I'm not sure how fast I'll drive on long trips in the future. If I'm totally out of line, please chastise me in this forum so I'll learn my lesson.
Offended? No. Chastise you? Not my place. Causes me agita? yup. My dad drove the DC beltway when the speed limit was 70mph his entire career. He
never exceeded 45mph. His right. Really. Funny that every car we owned during that period had some sort of damage to the rear of his car - some more than once - in what he explained as parking lot incidents where someone pulled in fast and hit him when he was parked. The VW Squareback was folded down over two inches at the bumper with the bend point at the rear wheel-wells. Parking lot, indeed. Contributory negligence?
Consider:
https://phys.org/news/2007-12-traffic-mystery-mathematicians.htmlAs a motorcyclist, the two-second rule is gospel, three seconds on dodgy road conditions. Of course, I match the speed of the faster drivers that are not lane-hopping to keep folks off the rear tire. I don’t hang out next to cages, or trucks - speed up to a gap beside me. Always open. Defensive driving. Driving to stay alive. In this case, speed saves. That same driving carries over to the car. What with all that practice, and my lightbulb reflexes, I've stayed out of trouble.
Proper following distance is something most motorists know nothing of. I’ve got a new VW with the assisted driving stuff, including adaptive cruise control and blind spot warning. I got into it this weekend with a friend about the adaptive speed control - his claim was that the gap was too large, and folks were always pulling in front of him, dropping him back further and in the traffic. In his car, it is turned off. I have other problems with the adaptive speed control, but that's for another time.
On a trip to Ohio with friends (we’re towing a small, flat trailer), he would constantly “yell” at his wife to “give him a fender” meaning pull up on the car next to her and close the gap so that person couldn’t move over. Yeah. Really nice.
Consider the modern GPS. It may give you 1/2 mile warning about an upcoming exit - but in traffic where everyone gives the other a fender, how does one navigate to the exit in 30 seconds - that is after five minutes ago, the damned thing said to be in the left lane.
I’ve mentioned the ridiculously slow, mathematical analysis of slowdowns without cause, and the aggressive drivers (though THEY wouldn’t admit it…). And following distances. A new subject that galls me to no end is the
“Hill Delay”. Starts with a dead-foot driver that will slow down 5, 10, 15, even 20mph going up a moderate hill. Then the accordion effect starts. Drivers slow down, reduce their already inadequate following distances, and that propagates back down the hill. Drivers start changing lanes, exacerbating the slowdowns.
In the meantime, the slow car has crested the hill and is now speeding up. It takes time for that accordion to expand again, and then comes the next hill. Ol' Dead-foot does it again. In heavy traffic there is no relief going down the hill because all that slowdown crept backwards to the crest of the last hill. Dead-foot has done their damage, blissfully unaware. See it in action on 95 between Richmond and DC, always worse going north.
Slower drivers also cause the other driver, even at speed limit, to have to change lanes. Light traffic is no problem. Moderate traffic and the maneuver becomes more dicy. Some people can’t look over their shoulder, and some just don’t. Of course that means everyone in that lane needs to slow down to maintain their (inadequate) following distance. And then the mathematical analysis linked above starts.
Of course, with the new driver aids on the new cars, things are safer - blind spot warning, adaptive speed control, lane assist. Well, not really. Lane assist in many cars has an audible warning plus some type of inane international icon attempting to communicate the driver fault.
Blind spot warning has a little icon that appears on the mirror that lights when there is a car there.
Most don’t either don’t see them, or annoyed by the sound. Some take the car back to the dealer wondering what that intermittent, annoying beeping is - Well, it’s a safety feature they say, and then the driver has that turned off then and there.
My wife had her VW for a month and saw the little icons in the mirrors but did not know what they were, did not ask, and just ignored them. Of course she could have turned them off with controls on the steering wheel, but that would have meant she knew what they were in the first place, and had the curiosity to figure out the menuing system provided by VW to control various aspects of the car. To her credit, she did figure out the following too close display, and heeds it.
Also consider - a hose will only flow as much water as the smallest restriction in the hose allows.
I’m sorry. IMNTBHO, Not keeping up with traffic is dangerous. ZipZoom through the traffic, while very dangerous, those maniacal drivers are there and gone and no longer an immediate danger once past. Given the choice, I'd choose the maniac. I can spot those a mile away.
frank
