If Driving Over The Speed Limit, Stop Complaining About Gas Prices

reply to post by cautiouslypessimistic

It makes perfect sense and, not to be rude, but I have to laugh at how far over everyone's head this topic is.

they are going the same speed over different distances, meaning the further you go at a more efficient speed, the higher your average mpg will be. Afterall, mpg is nothing more than an average, and if you get higher efficiency over a longer period of time, the average will raise.

Seems a lot of people on this board missed out on math.

How much gas do you think it takes to accelerate a car up to 90 mph? If it takes 10 seconds to get up to speed, the difference in the average miles per gallon between two identical cars is negligible. Yeah, after the first car stops at 30 miles and the other continues for another 170, it doesn't have to re-accelerate. But that is only 10 seconds of acceleration which burns a negligible amount of fuel compared to 10 seconds of already going 90mph.

You originally said...

You will get noticably better mileage on the second trip, because you have a greater amount of distance to make up for the disporportionate amount of fuel used to accelerate to 90 mph.

So, where then is this noticeably better mileage if there is no disproportiante amount of fuel used?

I don't understand claims of speed having a limited effect on MPG. Regardless of the aerodynamics of the vehicle there is still drag from the force of air. The faster your are moving the more force being implied!

Originally posted by TheHunted
reply to post by cautiouslypessimistic

 

You have to provide some proof of this peak rate you speak of. I've provided facts with clear evidence that driving slower regardless of aerodynamics increases fuel economy.

You have provided no proof. The only thing you have provided proof of is that wind resistance effects mileage. Bottom line, research a topic before you speak on it.

Originally posted by Evil Genius


So, where then is this noticeably better mileage if there is no disproportiante amount of fuel used?

Ten seconds of hard acceleration in any car would lower the mpg for that time period subtantially. If you track your mpg, you WILL notice at least a +1 or 2 in mpg over the longer distance, which is noticable difference.

reply to post by cautiouslypessimistic

Ten seconds of hard acceleration in any car would lower the mpg for that time period subtantially. If you track your mpg, you WILL notice at least a +1 or 2 in mpg over the longer distance, which is noticable difference.

You're making statements that you can't back up with the numbers.

I'm going to use my car as an example to prove you wrong. I drive a 2006 Eclipse which according to Cars.com gets 18-23 MPG in the city and 27-30 MPG on the highway. While going 90 mph is very inefficient I'm going to use the high end value of 30MPG just to make the math easier.

I'll drive the short distance and I'll let you take the long distance. We both have a full tank and accelerate at the same rate up to 90mph which takes 10 seconds. My drive is 30 miles long, which will take 20 minutes (1200 seconds) going 90mph. Since, I get 30MPG on the highway, I will use up 1 gallon of gas during that 30 mile trip. Now, out of the time spent on the road which is 1200 seconds, I am accelerating for 10 seconds. That means I was accelerating for less than 1% of the time I was using gas. It actually comes out to 0.8%.

I'm going to adjust your mileage a bit and say you continue on for a total of 180 miles. This will take you 2 hours (7200 seconds). Since you also get 30 MPG on the highway you will use up 6 gallons of gas. Out of the time you spent on the highway which is 7200 seconds, you were accelerating for 10 seconds. That means you accelerated for less than 1% of the time you were using gas as well. It comes out to 0.1% of the time.

The difference between 0.8% and 0.1% is negligible.

You used 6 gallons to my 1 gallon. You said you WILL see at least 2 mpg more. So, by your reasoning, the 5 gallons you used after I stopped means you should be able to drive an additional 10 miles more than me, just because you didn't have to accelerate a second time. I hope you see how absurd that sounds. By that rationale, the difference between the city mpg and the highway mpg should be much greater as we are constantly having to accelerate in the city. But the difference for an Eclipse is 7 MPG from city to highway.

1 acceleration does nothing to affect the distance we will be able to drive.

reply to post by cautiouslypessimistic


Actually if you look back I have provided proof of both. All you have done is claimed that the faster you cover ground the less fuel used. You have done this without providing any form of solid proof. Which shows that you have done no research.

This thread just goes to show that everyone is all for ways to reduce demand for fuel, unless it requires them to alter thier habits. Someone said that each car has it's own peak efficiency, and that is very true,but I highly doubt that any car's peak efficiency is over 80 mph hwy. I've done a bit of research on it and it seems to be in the 50-70mph range for most cars, and less for SUVs and trucks.

I take sadistic joy in slowing down while being tailgated by an SUV, especially on the semi-rural roads that I drive to and from home on. When I first started driving, the speed limit was either still 55 or had just been increased to 65. It wouldn't hurt my feelings to go back there. I'm willing to make that slight sacrifice of my time.

From Cars.com:

Top speed also plays a part. Most vehicles are most efficient when cruising in their top gear at a relatively low speed. For example, a car with a five-speed transmission would be most efficient in 5th gear at 40 to 55 mph. Wind resistance increases exponentially with speed, so as your pace increases from this point, fuel economy drops dramatically. Onboard trip computers that show instantaneous and average fuel economy are remarkably accurate. Keep an eye on this and you'll learn how to drive in a miserly fashion.

Or is this false as well?

As incredible as it may seem, if the average car was as efficient as a racing bicycle it would be capable of getting over 2000 mpg. The limiting factor is mainly weight and friction on the car. Now I'm not negating the effects of wind resistance because that is the most limiting factor on a skinny little dude on a skinny little bike. Ride one into a 20 mpg headwind using a cyclometer to measure your average speed,say for 10 miles Do an about face and do the same exerting the same amount of effort and see what you come up with. This experiment will teach you about all that you need to know about the effects of the wind on a moving object.

Originally posted by Scorched Earth
Just like I told the cop that pulled me over a few weeks ago, unless the city is willing to compensate me for the gas I spend sitting at uncoordinated traffic lights, I will drive over the speed limit to make up lost time.]

So you were speeding to save time? Not only did you waste fuel, you received a speeding ticket in the process. Then there is the lost time while being pulled over. Sounds like it all worked out for you.......

I stay in the right lanes. California has signs all along the freeways that say slower traffic to the right. However, Arizona does not and it is chaos.

Originally posted by SailorinAZ
I stay in the right lanes. California has signs all along the freeways that say slower traffic to the right. However, Arizona does not and it is chaos.

That's how it was when I was stationed in Texas. It does, makes plenty of sense. Especially when you have every vehicle going a different speed. But I believe these signs mean if you are going under the speed limit to stay to the right. If you are doing the speed limit then stay left. If not sounds like a promotion of speeding...

Click here for more information.

reply to post by cautiouslypessimistic


Ok great , but I will end it like this. Just because you have explained your STORY twice does not make it fact. I also believe your STORY belongs in Mysterious Creatures forum because it is as true as the latest Big Foot hoax.

I will not resort to personal insults like yourself. ATS is about Denying Ignorance! So you are Denied!!!

So on my way to work today a F-250 flies by me on the express way. I was doing 70 which is the speed limit, the truck must have been going 85. Anyways, I get off at my exit where there is a stop lights at the end of the ramp. Sitting there is the truck waiting for me is the same truck. Just another example of easy money being made by oil companies....

Originally posted by TheHunted
So on my way to work today a F-250 flies by me on the express way. I was doing 70 which is the speed limit, the truck must have been going 85. Anyways, I get off at my exit where there is a stop lights at the end of the ramp. Sitting there is the truck waiting for me is the same truck. Just another example of easy money being made by oil companies....

Ahhh yes, because, had he been doing 70, he would NEVER RUN OUT OF GAS! AHAHAHAHA you figured it out.
C'mon man.

reply to post by TheHunted


Stoplights....the equalizers.
This phenomenon happens to me all the time. I've noticed it from both sides of the coin, a few times I was the "speeder" and got around "that slow dude" only to have him tool up beside or behind me at some stoplight 3 towns up the road.
I drive way more mellow now with the high gas prices and have noticed my mileage go from 27-28, to 32-33.
At current prices this saves me around 200 bucks a year. Worth it? Maybe

Originally posted by tjack
reply to post by TheHunted

 

Stoplights....the equalizers.
This phenomenon happens to me all the time. I've noticed it from both sides of the coin, a few times I was the "speeder" and got around "that slow dude" only to have him tool up beside or behind me at some stoplight 3 towns up the road.
I drive way more mellow now with the high gas prices and have noticed my mileage go from 27-28, to 32-33.
At current prices this saves me around 200 bucks a year. Worth it? Maybe

How many miles do you drive a week? I'm stuck driving to work 47 miles one way. Dropped my speed to 67 mph and use 5.5 gallons less of fuel a week. That's a huge savings for me over the year. I also do this hoping others will drive more sensible. I have seen the price of fuel drop some recently. The more people that drive slower maybe the faster the price of fuel drops. That would be nice....

reply to post by TheHunted


I have a 36 mile round-trip to work, so that's about 180, so I'd say around 200 miles a week.


edit to add:
Surprisingly I've also noticed others driving more conservatively as well, and that blows my mind. If CT (the state) drivers can tone it down a notch, everybody should be able to

[edit on 27-8-2008 by tjack]

reply to post by tjack


That's awesome to hear about drivers in CT. Michigan drives it's you move it or lose it. So I go ahead and drive in the middle lane. Makes people mad, but I obeying the law.

You do have to aquire a patience to slow down, but it can be done. Never seen much sense in giving away free money to the greedy. Not even one dollar..