Is going 55 mph really the best speed?

[fatlard]

I know many of you expressed going 55 mph the best speed but is that really the optimal point if you want to keep up with traffic while at the same time getting decent fuel economy

[frownonfun]

i know it's not the optimal speed if your goal is to ALSO keep up with traffic. not in a 70mph zone anyway. i have a scooter that tops out at about 55-60 and i've had it out on the highway a few times. it's downright terrifying.

[malibuguy]

its the best mileage parked in your driveway while you ride a bicycle...

[thebarber]

you want the lowest speed in the highest gear....

best mileage i ever got was 5.5L/100km (43mpg) while doing about 80-85km/h (50mph) on back roads in 5th gear. i accelerated slowly and downshifted while slowing down so the injectors don't run (vs neutral)

this was all during my 1000km engine break-in period...

ive never got that great an economy since, lol

[2009Toyotoad]

Thought I read elsewhere on the forum that 68 mph was the optimal speed. That's usually my commute speed at 5:00 A.M. and 2:30 P.M. and the mpg is consistently 40.5 to 41.5.

edit: I'm feeling a little inspired this week, particularly today. I noted that today was "ride your bicycle to work day," and while that's not practical for me, running 55 mph during my commute was a resonable alternative. Looking forward to seeing my mpg numbers for the week.

[STC]

Maybe President Jimmy Carter knew what he was talking about? Eh? Of course he did... and it saves lives too!

Cheers!

[rningonfumes]

LOL, going 55 with no metal cage around you will terrifying to anyone if cars are constantly passing you up.

Look if you want to do it, go ahead you'll get used to it, the fear of being hit will subside. Think about it this way, if you wouldn't want your front end hitting the back end of another car, why would other drivers want any different? Those drivers breathing down your ass won't want anything happening to their precious cars.

The argument about holding up traffic? I consider it null as along as you're on the far right on a major multi lane freeway. If a driver has a problem with not being able to use the far right to pass cars, the driver has problem because the far right is not a passing lane.

Basically do everything you can to help out the flow. I've notice that if the flow is high, the freeway is most likely open and there's room for people to pass on the left. If the flow is slow, there must be congestion, speeds as a whole are low. When traffic is high with high speeds? People like to travel in packs, that current pack of cars will pass soon enough.

Edit:

Use psychology, I've said this before to follow a truck, not for drafting purposes but to make people think it's the truck that is slow. People will see the truck before they see you and will prepare to pass you.

[SKurj]

Until this past winter I was always in the fast lane always 120-140kmh and over the winter months rarely getting more than 550kms to a tank. This winter I backed it off, kept speeds 110ish and 650kms per tank has been rather easily accomplished, sometimes closing on 700kms...

Thats with the 04 echo HB which has 258,000kms on it... The new Yaris seems to be around the same mebbe a tiny bit better

[fatlard]

Well at cruise control at 55mph with a sedan auto have given 47mpg.... I guess I will stay at that speed

[why?]

55 was never the best speed for anything. It is really relative to a ton of stuff, and finding what is best for you takes time and lots of experimenting.

[Idahotom]

My main drive is a 45 mph secondary road I drive at 47 (cruise set) and on the few level stretchs my ScanGauge always shows very high 40's MPG. Low 50's if I have a tailwind!

[fatlard]

So.. this past weekend, I drove 70mph on cruise control this weekend for about 200 miles and I got 45 mpg... so I am as confused as ever.... just more data.

[daf62757]

Originally Posted by fatlard

So.. this past weekend, I drove 70mph on cruise control this weekend for about 200 miles and I got 45 mpg... so I am as confused as ever.... just more data.

Could have been you had a great tailwind....flat terrain....or your Yaris was just in the "zone"!

[daf62757]

Originally Posted by STC

Maybe President Jimmy Carter knew what he was talking about? Eh? Of course he did... and it saves lives too!

Cheers!

Jimmy Carter? Wow...now I am going to have nightmares!

[daf62757]

Originally Posted by fatlard

I know many of you expressed going 55 mph the best speed but is that really the optimal point if you want to keep up with traffic while at the same time getting decent fuel economy

Here in Indiana, on the interstates, you would be a road hazard. You would save money, but it actually wouldn't be safe. 65 MPH is a better speed here for safety and it lets you keep up with the 18 wheelers.

Maybe on a state highway its a safe speed, but in too many places, you are an obstacle that people have to go around.

[BEEF]

looking at it strictly scientifically

I have seen graphs on aerodynamic drag that show there is a deflection point where drag increases sharply. the sharp increase is usually between 50 and 60 mph depending on the aerodynamics of the particular vehicle. I know I saw one that showed the optimum for a vehicle being 53MPH. I can't remember what vehicle was tested but I do remember it being old.

that may be where the whole 55MPH thing came from. it gives you the most speed for the least amount of drag.

there again, I may be reading way too much into the question.

[TLyttle]

Somehow, it is the "saving lives" thing that got me. What was it? 40%? What a bonus, even if the percentage is wrong! Nowadays, the cars are keeping the numbers of deaths down, not the drivers: speed limits keep climbing, and US oil dependency follows suit.

Keep up to busy traffic, play P&G when one is on one's own, or whatever fuel-saving game one is into. Myself, I feel that I am driving one of the most fuel-efficent vehicles around, and the savings by hypermiling really ain't gonna make a big difference, considering how much fuel I COULD be burning...

[frownonfun]

I hate to burst anyone's bubble but there is no real solid data that shows that having a national 55mph speed limit saved lives. Not only can it be shown that there were less annual deaths in some years before the Emergency Highway Energy Conservation Act was enacted but you also have to consider that even in the years there were fewer deaths during that period there were also less people on the road to begin with because of the oil crisis that prompted the passing of the EHECA in the first place.

Just sayin.