Anyone think BHO/Congress will bring back the nationwide 55MPH speed limit?

[Q451990]

As I have been thinking about hedging my bets against the inevitable I have been trying to anticipate how the election results will impact me. Aside from the drilling my wallet will probably take, what else with directly impact me?

Here's my list so far:

1) That whole SCHIP $10/stick tax on cigars that couldn't make it through last year. Sometime in the next few months I'm going to hoard boxes of them at the "pre embargo" price.

2) Ammo. I'm good on the guns... but they might tax or otherwise limit ability to buy the ammunition. Time to hoard that too.

and then it occured to me... these bastards will probably bring the "double nickle" back to please the tree huggers. Of the three I think this would have the most impact on my daily life. My only hope is that our more conservative state would make interstate speeding violations cheap, non point violations... but we love our revenue as much as anyone else, so that's doubtful.

I figure if I'm worrying about it - I should suggest it so you guys can share the curse with me.

Heath

[smockers83]

I say nay to the 55. Obama is a flashy guy, he'll want to drive his fancy car fast as well. Paring down the speed limit slows down commerce and would lengthen drives to unbearable times. It wouldn't pass if he did bring it up.

[marlin29311]

If oil prices hold steady and we're not paying $5 a gallon for fuel, I'd say no way either. Main concerns on national speed limits has always been about gas mileage (supposively...) - as long as it steadys out there should be no issues.

[Q451990]

I say nay to the 55. Obama is a flashy guy, he'll want to drive his fancy car fast as well.

I hope you're right. But who would give the pres. a speeding ticket?

If oil prices hold steady and we're not paying $5 a gallon for fuel, I'd say no way either. Main concerns on national speed limits has always been about gas mileage (supposively...) - as long as it steadys out there should be no issues.

I tend to agree... if gas prices stay low we may be OK, but I suspect we'll be right back up there at $3.50-$4.00/gal next summer unless the economy tanks and no one can afford it - keeping demand low.

Heath

[smockers83]

Main concerns on national speed limits has always been about gas mileage (supposively...)

Definitely supposedly. Each car is different in terms of gas mileage and speed. It all depends on the power being produced and the drag, where each model is different. I know with my G I get better mileage driving 80-85 instead of at the speed limit of 70 on the freeways, and its probably the same driving at 65. Personally, I think its all about safety and the quality of the cars being produced.

[C-Kwik]

Definitely supposedly. Each car is different in terms of gas mileage and speed. It all depends on the power being produced and the drag, where each model is different. I know with my G I get better mileage driving 80-85 instead of at the speed limit of 70 on the freeways, and its probably the same driving at 65. Personally, I think its all about safety and the quality of the cars being produced.

Doubtful. The power needed to propel a car at a particular speed requires a particular amount of power. Aerodynamic drag increases with the square of speed. As such the relationship between power required and speed is not-linear. Add to that, that your top gear is a fixed ratio and the increased engine speed will increase with vehicle speed. As the engine internals are not operating within a vacuum, it will also be subject to the increasing aerodynamic drag placed on the engine's internals. I don't support a lower speed limit, but the physics of lowering gas mileage is correct. Keep in mind that I had a G. I can't recall numbers, but the fuel consumption meter on the navigation system definitely showed a lower fuel consumption at 80-85 than at 70. Hell, I got some damned good gas mileage in it at 55 mph. Of course, that was a rare sight for me.

[smockers83]

You couldn't have let me feel at least a little bit smart?

[OriginalWheelman]

The Federal government does not have the right to set speed limits.

[Cold_Zero]

2) Ammo. I'm good on the guns... but they might tax or otherwise limit ability to buy the ammunition. Time to hoard that too.

Ammunition is taxed at a Federal Level. Of which a portion of that is/has been put away in a trust to improve shooting ranges around the United States. The Clinton Administration raided that fund and told the Department of Interior to go spend the money.

[Cold_Zero]

The Federal government does not have the right to set speed limits.

Sure they can, by limiting Federal Highway funds to any state that establishes a speed limit over 55 (in this example).

[audtatious]

I hope you're right. But who would give the pres. a speeding ticket?

A Republican cop

[Q451990]

[marlin29311]

Doubtful. The power needed to propel a car at a particular speed requires a particular amount of power. Aerodynamic drag increases with the square of speed. As such the relationship between power required and speed is not-linear. Add to that, that your top gear is a fixed ratio and the increased engine speed will increase with vehicle speed. As the engine internals are not operating within a vacuum, it will also be subject to the increasing aerodynamic drag placed on the engine's internals. I don't support a lower speed limit, but the physics of lowering gas mileage is correct. Keep in mind that I had a G. I can't recall numbers, but the fuel consumption meter on the navigation system definitely showed a lower fuel consumption at 80-85 than at 70. Hell, I got some damned good gas mileage in it at 55 mph. Of course, that was a rare sight for me.

Consumption is certianly lower at lower speeds, but the question is really does the increase in speed and distance traveled offset the increased burning of fuel? I think that's more in tune with what Eric was going for...

[smockers83]

Consumption is certianly lower at lower speeds, but the question is really does the increase in speed and distance traveled offset the increased burning of fuel? I think that's more in tune with what Eric was going for...

Yeah, something like that. I don't know the exact science behind it, but what I was trying to get at is that each car has its optimum speed in terms of gas mileage. How different that is, I'm not sure, I just know that for speed, distance, and time, I see the most benefits right around 80 MPH when I'm on the freeway and I'm sure its not the same for everyone. They say drag increases exponentially as speed increases, but wouldn't that have to do with the drag coefficient wherein that a car with a smaller drag coeff would be able to burn a lot less fuel than a car with a higher coeff as speed increased? It also has to do with the engine, too, I would have to imagine.

Maybe something more like this. Have the freeway system and highway system. For the freeways, find a speed that is nationally averaged to be the optimum speed for mileage driven and time in terms of total fuel consumption, not MPGs because they aren't linear. For the highways, have a slower speed that optimizes consumption as well with the same parameters. Maybe that's still 55, maybe its 60 or 65. The highways I travel, people do 65 most of the time anyway. Also, within cities, speeds should be optimized given how heavy traffic is, whether its one way or not, and all lights should be timed in such a way to improve gas consumption and flow.

I'm gonna get shut down on my science again, haha.

[OriginalWheelman]

Sure they can, by limiting Federal Highway funds to any state that establishes a speed limit over 55 (in this example).

Yup that's exactly how they kept it in place for all those years. Nothing more than a bully tactic. I never agreed with this and I never will.

A Republican cop

Actually, almost all the cops I know are Republicans.

[C-Kwik]

Consumption is certianly lower at lower speeds, but the question is really does the increase in speed and distance traveled offset the increased burning of fuel? I think that's more in tune with what Eric was going for...

I stated before that the relationship between speed and power needed is not linear. Basically as speed goes up, fuel consumption goes as a function of distance. This is because of the fact that it requires 4 times as much power to double the speed due to aerodynamic drag. As power is dependent on how much energy is being consumed, the energy consumption goes up at the same rate as power. The only real unknown that could be thrown in is a huge jump in the efficiency of turning fuel energy into mechanical energy. But it would be unlikely that tehre would be such a sharp increase as the amount of power needed to overcome the additional windage losses from increasing engine speed would subtract from any additional mechanical energy that becomes available.

[marlin29311]

I stated before that the relationship between speed and power needed is not linear. Basically as speed goes up, fuel consumption goes as a function of distance. This is because of the fact that it requires 4 times as much power to double the speed due to aerodynamic drag. As power is dependent on how much energy is being consumed, the energy consumption goes up at the same rate as power. The only real unknown that could be thrown in is a huge jump in the efficiency of turning fuel energy into mechanical energy. But it would be unlikely that tehre would be such a sharp increase as the amount of power needed to overcome the additional windage losses from increasing engine speed would subtract from any additional mechanical energy that becomes available.

.....fffffffffffffffffffffffffffffffffff............... that's the sound of that entire post going over my head...

So how does whatever you just said impact the "sweet spot" of a car in terms of mpg's?

[C-Kwik]

So how does whatever you just said impact the "sweet spot" of a car in terms of mpg's?

The sweet spot doesn't change for a given set of variables as the car, engine and transmission are the same. Other variables are going to be wind, air density, how level the road is, etc, etc, etc. But those variables would remain fixed if one is going to try and compare mpg vs speed. That said, the best mpg is likely going to be in top gear, at the lowest engine speed you can run without lugging it. The actual calculation of it would be extremely complex as there are so many variables (which means you have to combine a crap load of equations and solve for the value you want). My post only outlined the biggest factors when it comes to the differences in gas mileage at different speeds.

[wingFeather]

I get better MPG at 68 than I do at 55 (and this is observed on two different cars).