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from the Wir-fahr'n-fahr'n-fahr'n-auf-der-Autobahn dept.
Brought to the floor by Senator John Moorlach of Orange County, SB-319 would direct the state's Department of Transportation to build two unlimited speed lanes on each side of Interstate 5 and State Route 99, the main north-south arteries linking cities like Los Angeles, San Francisco, and Sacramento. The sections of the roadways in question run straight through the supremely flat Central Valley, making for ideal high-speed driving conditions.
Perhaps paradoxically, California's answer to the German autobahn would be paid for by the state's Greenhouse Gas Reduction Fund. The text of SB-319 points out that the recent collapse of California's ambitious plan for a bullet train between Los Angeles and San Francisco, which was originally intended to trace the same route as the proposed unlimited speed lanes, has left residents without "access to high-speed, unabated transportation across the state."
http://www.thedrive.com/news/26554/california-might-add-lanes-with-no-speed-limits-to-major-highways
(Score: 2) by mendax on Wednesday February 20 2019, @12:40AM (16 children)
High-speed automobile driving increases greenhouse gas emissions. A car going 120 mph will use twice as much fuel as that same car going 60 mph. If this idiot senator is really serious about green house gas emissions, he'd sponsor a bill reducing the speed limit to 60 mph state wide. Cars would get much better mileage than they do now going 70 mph, the state's highest speed limit.
It's really quite a simple choice: Life, Death, or Los Angeles.
(Score: 3, Interesting) by krishnoid on Wednesday February 20 2019, @01:08AM
Restrict use to electric vehicles. I bet it would increase sales!
(Score: 1, Touché) by Anonymous Coward on Wednesday February 20 2019, @01:38AM (5 children)
"A car going 120 mph will use twice as much fuel as that same car going 60 mph." No difference.
(Score: 0) by Anonymous Coward on Wednesday February 20 2019, @01:07PM
Actually... I get an average 24mpg on congested Cali hwys where you're always transitioning from 50mph to 70mph, and 44mpg when traffic clears out and I cruise at 85mph. It's a steady speed that increases mpg. Even at 85mph... there are cars passing me.
(Score: 1, Insightful) by Anonymous Coward on Wednesday February 20 2019, @02:27PM (3 children)
There fixed that for you.
(Score: 0) by Anonymous Coward on Wednesday February 20 2019, @03:32PM
Go back to Jr High science class, you failed the 1st time.
(Score: 2) by Runaway1956 on Wednesday February 20 2019, @04:01PM (1 child)
I hope I can offer a little insight here. Pretty much every model of car is engineered for a certain type of travel, and performance. I have found vehicles, such as you describe, which use inordinate amounts of fuel, when traveling at highway speeds. There are many cars which DO NOT use excessive fuel at high speeds. Engineering is everything, here. If your engine is cranking at 12,000 RPM, you're getting shit for fuel economy, even if you're only going 35 mph. If your engine is idling around 3,000 to 4,000 RPM at 80, 100, or even more, then you might be getting some pretty good mileage. Get with the engineers, and find out what the car was designed for.
The point that the other AC is trying to make, is that a car uses fuel quicker at high speeds - but it also goes more miles in that same time. You use more fuel to generate those extra horsepower, but you need those horses for a shorter period of time, so you don't have to feed them so long. Take that back to how the car is engineered.
Yes, wind resistance is a factor, but no, wind resistance is as big a factor as some people think.
All I ask is, before you conclude that faster cars are using twice as much gas, you should check those cars out. I have a few anecdotes about vehicles getting BETTER fuel mileage at higher speeds, and many more that got nearly the same mileage. Since I don't buy slow vehicles, I don't have examples of vehicles whose mileage went to hell between 60 and 100.
(Score: 0) by Anonymous Coward on Thursday February 21 2019, @02:02PM
Gear ratio counts for the most part. Low RPM, less fuel used, although engines have optimal RPM range, but you know. Now that cars have 6-7 gears, even high speed driving can be driven in low RPM.
As a side note, i don't know what kind of cars you drive, but normally cars run at 1000-3000 RPM in regular traffic.
(Score: 5, Informative) by c0lo on Wednesday February 20 2019, @02:22AM (8 children)
Nope, under ideal conditions, the dependence is quadratic.
1. a car accelerating to 120mph will use at least 4 times as much fuel as the same car accelerating to only 60mph (hint: kinetic energy scaling with the square of the speed)
2. the (aerodynamic) drag scales at least quadratic with the speed, the drag equation [wikipedia.org] guarantees it. It can scale even more if the Reynolds number also depends on the speed.
That being said, one needs to take into consideration, in extreme, the effect of idling your ICE while stuck in traffic.
In practice, there will always exist a speed that any car is the most efficient in terms of fuel economy (in given conditions). In considering this, on top of the drag, up/downhill, tire frictions, etc, the engine efficiency map plays a role (an example of efficiency map [nap.edu]).
Now, if we are taking about eVehicles, idling doesn't matter that much and "is it green or not" boils down to on the source of electricity you used to fill-up the battery.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by mendax on Wednesday February 20 2019, @05:42AM
I stand corrected. Physics is not one of my strong points. But I think I made my point quite adequately.
It's really quite a simple choice: Life, Death, or Los Angeles.
(Score: 0) by Anonymous Coward on Wednesday February 20 2019, @02:18PM (4 children)
Ok, let's talk about *speed* not *accelerating*. Don't confuse the two. KE is about speed, not accelerating. You want accelerating, you integrate. Also, don't talk about Raynold's number. That's from fluid mechanics and doesn't really apply here (think, speed of sound).
Also, you are wrong, it's 2x. It's 4x the energy (due to drag) to travel at 2x the speed. Since you get there 2x faster, 4/2=2.... ok? So, naively speaking, traveling at 2x the speed will burn 2x the gas, roughly speaking, for same journey.. Traveling at 4x the speed will burn 4x the gas...
ratio is v^2 (from drag) / v (from distance) so energy used to travel some distance is linear with speed.
Now, if you want to talk about accelerations, it's completely different game that is quite independent of the actual speed. ;)
QED.
(Score: 2) by c0lo on Wednesday February 20 2019, @03:32PM (3 children)
Fuel consumption proportional with energy you spend to achieve the work.
Let's talk about energy:
- on the accelerating side of the travel to reach the cruising speed from zero, you'll consume an energy proportional with the final kinetic energy, thus the square of the speed. Integrate all you want you aren't getting anything else (and this expenditure is relevant driving in heavy traffic, when you have cycles of acceleration/braking).
- travelling at constant speed - for the same vehicle, the aerodynamic drag makes the only difference when it comes to travelling the same distance at different speeds. And the aerodynamic drag force scales with the square of the speed (in both laminar and turbulent cases, only the scaling factor is different between the two). Now, the energy expenditure against the aerodynamic drag is drag_force × distance (this is what your integration reduces to at constant speed). For the same distance travelled, will get to an energy expenditure going quadratic with the speed (plus the same energy in both cases lost due to friction with the road, which is independent of the speed)
Ummm... what exactly do you think you demonstrated?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Immerman on Wednesday February 20 2019, @04:09PM (2 children)
Absolutely correct. Worth mentioning as well that by the time you hit around 60mph, air resistance is generally the primary source of energy loss. Quadruple that by doubling your speed, and while you won't have quite 4x the total energy consumption per mile, you will almost certainly be well over 2x.
(Score: 2) by c0lo on Wednesday February 20 2019, @04:28PM (1 child)
Yeah, switching between algo complexity and physics equations becomes harder with age - that friction term isn't quite ignorable in physics.
A more refined model will take into consideration the mass of the fuel burnt by ICE over the travel - the crews in F1 races certainly don't ignore it.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Immerman on Wednesday February 20 2019, @04:54PM
Quite - without regenerative braking, acceleration can become a significant source of energy loss as well, especially if traffic speed fluctuates frequently.
(Score: 2) by DeathMonkey on Wednesday February 20 2019, @06:40PM (1 child)
A car going 120 mph will use twice as much fuel as that same car going 60 mph.
Sorry, he forgot to mention you should assume a spherical car in a vacuum.
(Score: 2) by krishnoid on Thursday February 21 2019, @12:54AM
Ohhh ... so *that's* the idea behind the Boring Company.