Fuel Economy: Driving Under Speed Limit?

[VanForNow]

In the interest of saving $$$ on fuel, how many people drive under the speed limit?

If you do it, is it safe, and how many MPH do you drive under the limit?

 

[BradKW]

In my limited testing, my 7.3 diesel likes to drive 45-50 mph, getting 13 mpg. When traveling at 70, mpg drops to about 10. I'm fine with going 60 on freeways, but less than that can make you a nuisance and/or a hazard in some situations...

 

[speedhighway46]

Wow; great thread! One of my favorite subjects!

Although I'm no longer a commercial vehicle and technically not required to follow it, vehicles over 26,000 pounds in Michigan can only drive 60 mph on limited access highways.

I drive 58. Hey, I'm not in a hurry and it does wonders for my fuel mileage.

I have never had a problem; plus there is the left lane for anyone who wants to go around me. Frequently I have cars follow along behind me who have also decided to take it easy.

Practically, I have more stopping room; the crazies go around me; I can enjoy the scenery; and I have more "reflex" time to respond to emergency situations which may arise.

Lastly, it's more enjoyable.

 

[Almost There]

Here in Ontario the speed limit on some 4 lane highways is 90 kmh so 55 mph- I do the 55. Others are 100 kmh (62mph), I do maybe 95 unless I'm in a hurry and then I'll set cruise control on 100.

In some of the US states where the speed limit is 80 mph, I definitely stick to the right hand lane and do 60mph. I actually found last winter that a lot of the trucks were doing my speed as well....mostly the ones that had to pay for their own gas I'm betting!!

But then I also try to stay off the interstates anyways. On the blue roads I try to pretty much do the speed limit so as not to impede traffic but then the speed limits are much more in tune with how I drive anyways.

I like to lollygag around a lot and I also like the much improved gas mileage by going slower.

 

[Yogidog]

I poke along, especially now in four cylinder in the mountains, I do what the others suggested, often following a truck driver from a distance, many truckers know how to drive safely like fellow speedhighway. I always get to right lane as soon as possible.

 

[LeeRevell]

I use my cruise control to drive just one or two MPH over the limit. I find mileage is best generally at the limit, though here in Florida we do have some areas with the posted limit at 65MPH. Mostly I am in the 45/55MPH zones.
I find vehicle weight and driving habits affect my mileage far more than the speed limit.

 

[poncho62]

I do the limit.....Mileage or not, I find it more stressful with a line of cars behind me, so I do the limit. That way, they have no excuse to be mad and if they want to go faster, they can pass.

 

[cyndi]

If I'm on the interstate, I generally do a few miles over the speed limit. it doesn't matter if the speed limit is 55 or 75. I try not to spend too much time on the interstate.

Seems like everywhere but TX the secondary highways are 55mph and that's what I do. It cracks me up that even the secondary highways in TX are 75

 

[wagoneer]

It's called the SPEED LIMIT or the fastest you can legally drive in that zone. My truck feels best at 55-60, some downhill stretches let me coast at 70.

 

[Suanne]

If I'm trying to put on the miles, like getting across Texas, I'll go the speed limit or slightly above. Usually I'm in no hurry and will take the secondary roads; and, if on the Interstate, I'll slide in behind a big rig whose going at the slower pace.

 

[rvpopeye]

I prefer to go 180-200 but the RV won't do it so I just let it go as fast as it wants to.

 

[Every Road Leads Home]

RV......Make sure to bring extra underpants if you're ever doing 200 in a Class C!

 

[Every Road Leads Home]

I live in Mass where if you're going 15mph over the speed limit you're getting honked at and passed like yesterday's trash. The cops are no better, they pass you going 90mph and ride your bumper til you get out of their way. That being said they don't seem to bother pulling anyone over until they are going about 20 over the 55 and 65 speed limits we have.

Once, I did 55 for about a month to see how it would help my mileage and I went from an average of 16 to 18 but honestly it felt dangerous because it was bottle necking everyone else and they were all flying around me any which way they could. When I travel around the country I prefer backroads because you see lots of little towns you'd never know about otherwise and you get the best scenery.

 

[rvpopeye]

It just won't do it !
I keep trying but it maxes out at 60.
It gets 6mpg at that speed so I try to keep it down anyway.
I'm never in a hurry anymore , so ...............
I'll wait for that Tesla !
Elon's going to give me one , are you reading this Mr Musk? I'm counting on ya bud !

 

[VanForNow]

...if on the Interstate, I'll slide in behind a big rig whose going at the slower pace.

I sometimes do this, too, but the problem is that 18-wheelers with heavy cargos tend to slow down a lot when climbing a hill. When this happens, I often get impatient and pass them.

 

[slem]

In the interest of saving $$$ on fuel, how many people drive under the speed limit?

If you do it, is it safe, and how many MPH do you drive under the limit?

Having been a semi truck driver for years I can offer this first hand experience.  Drive with the flow of traffic or at least the posted speed limit.  Pinching fuel is not worth a dangerous scenario.

Drivers who drive under the posted speed limit or those that sit in the passing lane (inside lane) promote danger to all who sharing the road.  Simply put you will be passed by faster traffic.   One of the greatest danger to fellow road sharers is when a semi is moving into the passing lane then back to the traffic lane.   Maneuvering around slow drivers requires threading in and out of the passing lane. Not good.  Keep in mind that you are not a speed enforcement cop. Driving the speed limit in the passing lane is dangerous requiring others to pass you on the right.  Very small thinking and extremely unhealthy.  

The last stat I looked at a couple years ago showed that we exterminated over 41,000 citizens on American road during a 12 month period. That is more lives lost on the highways than were lost in all of DoD (military) since the Vietnam war.

 

[jaxtonsgram]

, if on the Interstate, I'll slide in behind a big rig whose going at the slower pace.

Sort of off topic to mpg but do you rig drivers mind when we slip behind you and stay there as long as we're far enough back where you can see us in the mirror? I always wondered this. 
Nora

 

[wagoneer]

When you are in for the long haul you listen to the motor, the motor talks you listen. everyone else shut up.

 

[speedhighway46]

To clearify: regarding "keeping up with the flow of traffic" is not possible when you are driving in a state with split speed limits on limited access highways. When trucks are driving 60 and cars are driving 70 there is a built-in requirement for the faster vehicles to pass the slower vehicles.

If you are following a truck going 60 you are imposing no greater risk to the flow of traffic than a truck following another truck. It is the passing vehicle's burden to change lanes into the passing lane, pass the vehicle, and then return safely to the right lane. It doesn't matter if the faster vehicle is passing a car or a truck; it's all the same.

Logically, you are more effective driving safely at 60 than you are at 70.

 

[highdesertranger]

with my big ole heavy truck I am in the 50-60mph crowd. when climbing grades slower. if I am impeding other vehicles I pull over asap. highdesertranger