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| 5/25 |
| 2005/10/19-21 [Transportation/Car/RoadHogs, Transportation/Car/Hybrid] UID:40185 Activity:high |
10/19 Let's reinstate the 55mph limit. "For every mile per hour faster
than 55 mph, fuel economy drops by about 1 percent, said Jason Mark,
clean vehicles program director for the Union of Concerned Scientists.
The drop-off increases at a greater rate after 65 mph. The faster you
go, the faster the fuel goes." http://csua.org/u/dro
\_ my suggestion is impose $1.5 per gallon of federal tax on gasoline
and people will go green as result. We can use the money to
really fix the road and provide research funds for things like
automated highway, fuel cell research, etc.
\_ better yet, lets go back to walking, bicycles, and horse and buggy.
Gasoline usage drops 100%. Fatalities due to dangerous speeds
drop drastically too. No more dependence on foreign oil!
\_ Fuck speed limits. The average travel speed has been going down for
years, because on average people just keep spending more and more
time sitting in traffic. Throw in the extra time spent working to
pay for the stupid ass car habit, and you actually aren't going
any slower by biking to work. -anticartroll
\_ Since this seems to be "right vs. good" week, how about making it
voluntary? Educate people about how much they'll save, and they
can decide for themselves whether driving slow is worth it to them
on any given occasion. If you're worried that it's hard to drive
55 when everyone else is going 80, you could reserve some freeway
lanes for slow drivers, without mandating it for everyone all the
time. If your goal is to reduce dependence on oil rather than just
to save people money, then you can also impose extra taxes on oil
to encourage conservation -- not only will this make people drive
slower on average (while still allowing them to drive fast when
they need to), it'll also give them an incentive to save oil in
other ways (buying more efficient cars, closing the windows, etc.).
\_ Well, how fast will you be driving on the freeways?
\_ So how fast do you plan to drive on the freeway?
\_ I vote for 60mph. --- !PP
\_ Wouldn't this depend on which car? Maybe some cars get
optimal fuel efficiency at 55, and others at 70. Might
also depend if you are going uphill, have the windows open,
etc.
\_ Wind resistance roughly doubles between 55 mph and 70 mph.
At 55 mph, "tire resistance" and wind resistance for a typical
car are about equal. -!op
\_ I spent one week in truck doing 55 and the next week doing 70
to see how much I would save and my gas usage was about the same.
One week is most of a tank for me so it was enough data.
\_ I call bullshit on this. I've driven 101 from SF to LA plenty of
times in a BMW with a trip computer monitoring my fuel efficiency
and found that it was optimal (about 30mpg) at around 70mph.
\_ BMWs are fairly aerodynamic so they're impacted by wind
resistance at higher speeds. Their torque band also lies in
the 3000-5000 range which corresponds to about 70MPH. Not
all cars are like this.
\_ You're saying Jason Mark, clean vehicles program director for
the Union of Concerned Scientists, author of "Greener SUVs: A
Blueprint for Cleaner, More Efficient Light Trucks" and
"Zeroing Out Pollution: The Promise of Fuel Cell Vehicles",
doesn't know what he's talking about?
\_ I find all statistics suscpicious which don't allow for
different kinds of cars. If you really wanted to cut down
on gas consumption, think "trains". Anyway, regardles of
whether he's right or not (he's got a point about the wind
resistance, but it affects different cars differently), your
post reeks a bit of Mr. Science ("I have a master's degree..
in science!") -John
on gas consumption, think "trains". -John
\_ The problem is that it's impractical and dangerous to
have a different speed limit for each car model.
You need to find a composite speed limit that works
\_ Just tell cops to not give tickets to those of us who
are RICH WHITE MEN with GOOD CARS and everyone will
be happy. -John
best in the aggregate for the distribution of cars out
on the road. BTW, I should have made the sarcasm more
obvious when I tried to defer the the UCS guy's
authority. -pp
\_ Yup I hit 31 MPG, the highest I've ever seen, driving on HWY 5
@ 75 MPH in my Mercedes for a long stretch. No breaking, flat,
etc.
\_ I tried driving the long stretch on the San Mateo Bridge,
excluding the incline section, with my '04 Toyota Sienna 2WD van,
which is more aerodynamic than older minivans. I drove the whole
stretch at 55mph, then the whole stretch at 60mph, and again at
65mph. I reset the "average MPG meter" (whatever it's called) at
the beginning of each run, right after I passed the toll booth
and accelerated to the desired mph. For the 55mph and the 60mph
runs, the meter readings were roughly the same. But for the
65mph run, the reading was 2-3mph lower. I didn't use the
"instant MPG meter" because it fluctuates too much. -- yuen
\_ The 55 mph speed limit was based in part on the facts that
most cars at the time had poor areodynamic design and had
large engines (v6/v8) that were not particularly efficient.
In comparison most cars these days have better aerodynamic
design at all speeds and esp. at high speed (65+ mph). Also
most cars these days have smaller engines that are far more
efficient (there are far more c1v1cs on the road than hummers).
\- conserving to keep stuff cheep just lets other people
face lower prices. if you want to be active about something
then lobby for more research in alt energy. or maybe higher
taxes on gas if you want to punish people with big cars.
this drive 55 is like turn your thermostat down or do your
laundry at night. it's better to change the price structure.
\- should we have say quotas on home energy use? should
we have legal max thermostat settings?
\_ I don't believe in quotas, however I see no prob.
w/ imposing higher prices on ppl who use more than
the ave. (an luxury tax if you will - pg&e does
this already).
The legal max thermostat setting is an interesting
prob. If the purpose is to limit consumption, then
I think no, but if the purpose is to promote health
and safety (fire hazard, &c.), then I would say yes
b/c regualtion of health and safety is a traditional
concern of the state.
\- i have seen a number of these stats about the marked drop off
of efficiency at highers speeds in say AAA literature. i am
wondering if they forget or deliberately do not factor in
the greater distance travelled in unit time. e.g. there is a
difference between volume of fuel burned per minute at
55 vs 75 and then there is volume of fuel burned per *mile*
at 55 vs 75. ok tnx. --ANONYMOUS DRIVER
\_ Don't they usually report gas mileage to begin with?
\- i'm talking about stats like the one in the first
\P of this thread. you're not sure what they mean.
P[ost] of this thread. you're not sure what they mean.
\_ It's simple physics; power to overcome wind
resistance increases with the cube of velocity. -tom
\_ See the mpg vs. mph graph in
http://www.fueleconomy.gov/feg/driveHabits.shtml
"As a rule of thumb, you can assume that each 5 mph you drive over
60 mph is like paying an additional $0.21 per gallon for gas."
BTW, there are other useful gas-saving tips at
http://www.fueleconomy.gov/feg/drive.shtml
_________________________________________ |
| csua.org/u/dro -> sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/10/19/MNG3NFAOF11.DTL With gas prices hovering around $3 a gallon, a lot of people say they're making big sacrifices so they can afford to fill their gas tanks. They'r e cutting back on travel, curtailing shopping expeditions, going out les s often. But hardly anyone is talking about -- or practicing -- a surefire way to save on gas: Slow down. The drawbacks aren't measured just in terms of minutes lost. Th ere's the feeling of inadequacy that comes from being flipped off by a 1 2-year-old boy in another car. From being tailgated by little old ladies and pickup trucks piled high with furniture. From being passed by 830 v ehicles, including an AC Transit bus, on a drive from the Bay Area to de ep into the San Joaquin Valley. "It must have been a slow-traffic da y'' Traffic was a bit light when The Chronicle decided to take a 2001 Chevrol et Malibu for a 200-mile spin from Emeryville to the dusty Interstate 5 stopover of Kettleman City -- sticking to 55 mph on the way down and goi ng with the flow of traffic on the way back. The idea was to test just how much better the six-cylinder Malibu (EPA-es timated highway mileage: 29 miles per gallon) could do at a speed impose d on the nation's freeway drivers as a fuel-saving measure during the Ar ab oil embargo of the mid-1970s. The limit became increasingly unpopular and was repealed in 1995. Now you can do 65 mph on most of Interstate 580 in the East Bay all the way dow n to I-5, where 70 mph is the rule and 80 mph a common practice. The Malibu got 35 mpg on the way down to Kettleman City; coming back from the Kings County settle ment of fast-food restaurants and gas stations at the flow of traffic, a bit over 70 mph, the mileage dropped sharply -- to 25 mpg. "That's pretty significant,'' said Sean Comey, spokesman for AAA of North ern California. It took 49 minutes longer to make the trip at 55 mph -- three hours and 36 minutes total -- but it se emed like forever. Sitting in the slow lane, tapping the gas pedal to ma intain a steady speed, the car felt like it was traveling at 25. Everyth ing from Porsches and BMWs to big-rigs, the AC Transit bus and pickups t owing boats -- and they're supposed to keep their speeds under 55 -- cru ised past in the left lane. A lot of drivers cast curious glances at The Chronicle's Malibu, and a wo man in a black Volvo station wagon with three kids in the back seat glar ed. One person -- a preteen boy in the passenger seat of a Dodge Stratus -- made an obscene gesture, raising both middle fingers somewhere in Me rced County. A handful of drivers came within a few inches of the rear bumper before j erking their cars into the fast lane and flying by, but most simply pass ed. The 830 cars and trucks that went by the Malibu as it poked along at 55 mph was nearly 10 times the number that passed on the speedier trip home. Officer Panelli said the CHP sees very few drivers cruising I-5 at 55. It 's not illegal, however -- there's no minimum speed limit on that stretc h of road, and the Vehicle Code says only: "No person shall drive upon a highway at such a slow speed as to impede or block the normal and reaso nable movement of traffic." "You want to go with the fl ow,'' said Jihadda Govan of Delano, who was taking I-5 back from a weddi ng in Humboldt County. "You wouldn't want to sacrifice safety for fuel economy,'' he said. "I've never (responded to) a collision that occurred where someone said, 'This guy was driving 55 so I crashed into him,' '' he said. "We're coming from Seattle,'' said Hugh Lee, a content provider for an In ternet music service, bound for West Los Angeles with his friend, Leah C larin, a Nordstrom merchandiser. It was at 44 mpg, a bit better than the 42 he usual ly gets commuting to work in Hayward. He was trying to keep down his spe ed, he said, but wasn't too worried about the effect on mileage. Despite the significant fuel savings, there's been no hue and cry to rein state the national 55-mph speed limit. Castleman, who formed the Drive 5 5 Conservation Project as a way to lessen dependence on foreign oil afte r the terrorist attacks of Sept. "The 55 mph speed limit is not a number we're stuck on,'' he said. "The idea is to get people to slow down (and develop) an attitude of cons ervation,'' Castleman said. That makes sense to Mark, who said the savings can add up by slowing down even on short trips. He figures that a commuter making a 30-mile drive to work at 65 mph instead of 75 mph would save about 30 cents in fuel co sts per day -- or $150 a year -- and spend just 3 1/2 minutes more daily on the road. "When we're talking about changing driving habits, we're not talking abou t driving like your grandmother,'' Mark said. He drove from Emeryville to Kettleman City at 55 mph, then drove back at 70 mph and compared his gas mileage on the two trips . |
| www.fueleconomy.gov/feg/driveHabits.shtml More Info Driving More Efficiently Drive Sensibly cartoon of car Aggressive driving (speeding, rapid acceleration and braki ng) wastes gas. It can lower your gas mileage by 33 percent at highway s peeds and by 5 percent around town. Sensible driving is also safer for y ou and others, so you may save more than gas money. A n extra 100 pounds in your vehicle could reduce your MPG by up to 2%. Th e reduction is based on the percentage of extra weight relative to the v ehicle's weight and affects smaller vehicles more than larger ones. Cars with larger engines typically waste more gas at idle than do cars with smaller engines. Use Cruise Control Using cruise control on the highway helps you maintain a constant speed a nd, in most cases, will save gas. Use Overdrive Gears When you use overdrive gearing, your car's engine speed goes down. Data Sources Estimates for fuel savings from sensible driving are based on studies and literature reviews performed by Energy and Environmental Analysis, Inc. Estimates for the effect of speed on MPG are based on a study by West, B H, RN McGill, JW Hodgson, SS Sluder, and DE Smith, Development and Verification of Light-Duty Modal Emissions and Fuel Consumption Valu es for Traffic Models, Oak Ridge National Laboratory, Oak Ridge, Tenness ee, March 1999. |
| www.fueleconomy.gov/feg/drive.shtml More Info Gas Mileage Tips Here are some tips to help you reduce the amount of gas you use. If you a re already following these tips, you are probably getting the best gas m ileage your car can deliver. |