How far under the speed limit is it acceptable to drive?

Question

I found on several websites that the optimum speed limit for gas mileage is about 50 or 55 mph (see http://www.fueleconomy.gov/f*g/driveHabits.shtml), but the speed limit (at least on the highway out here) is 65 mph. I try to stay in the slow lane, but often there are pokes going slower than I (like tourists on cellphones...). I also try to stay between 60 & 65, but I think driving a bit slower might save some gas/money?

Answer 1

driving slower gets peoples nerves

and driving slower gets you to the place you want to be slower

so i dont see how that saves money and gas

Answer 2

Many of the interstates have a minimum speed of 40 MPH. This is primarily to keep the traffic flowing rather than conservation  or safety. If you have nowhere special to go or get to drive in the range which will give you the best mileage, no jackrabbit starts, only moderate acceleration and less braking than normal.

Answer 3

law also requires motorists to operate their vehicles in a careful and prudent manner and at a reduced rate of speed, taking into account the traffic, weather, visibility and road conditions.

Drivers must operate their vehicles with regard for the safety of people and property and in such a manner that they do not endanger the life, limb, property or other rights of people entitled to use the highways.

Drivers must be aware of:

the amount and type of traffic sharing the highway with them. The traffic may be heavy or light and may include trucks, cars, motor homes, farm equipment, motorcycles and bicycles.

changing weather conditions—fog, snow, water and ice, for example—that affect visibility and road conditions.

the type of vehicle being driven, particularly the condition of the brakes and the weight of the vehicle, which affects braking ability.

the character of the highway the driver is traveling. Drivers should adjust their speed for hills or for winding and narrow roads.

the presence of intersections, railway grade crossings or pedestrians.

Answer 4

It varies by state - 45 in most states is minimum, however when moving at that speed one must activate his/hers 4way flashers.

If one is traveling at a slower pace than posted speed, one is impeding the flow of traffic IF traffic cannot pass.

Also, even when you pass someone going slower than YOU, speed up to get around the slower person.

Answer 5

i think 45 mph

Answer 6

There really is not much difference between 55 and 65, you might save a few pennies but does not seem worth it to me.

Answer 7

45 mph is the minimum speed for a freeway.

Answer 8

10 miles over or under is a good rule of thumb

Answer 9

Yes but some people really get a tight jaw when they have to go under the speed limit..i say tough as if they are in that much of a hurry they should have left earlier..if they are late ..then its their own fault

I drive the speed that is safe and comfortable for me and as long as I am not in the passing lane...five under is OK with me

Answer 10

It will if you can bear the tailgating and horn honking.  Also, it only makes sense to drive that slow if you maintain your speed (i.e, with cruise control).  So if you find yourself speeding up everytime someone's riding your bumper, then you're better off setting the cruise at 65.

Answer 11

In California there is no minimum speed on a street.  On a freeway it's 45 mph, meaning you can (in theory) be ticketed for driving slower than that if traffic is flowing freely.  Of course, in reality the CHP doesn't really care;  I've never heard of anyone getting such a ticket.

Answer 12

The faster your engine is moving, the less gas you are going to consume. For example, when you slam on the gas peddle, you are using a ton of gas because the engine needs that energy to get it up to speed. Once you are at your desired speed, the engine does not use as much gas because it has already gotten up to speed. The best thing to do is to accelerate slowly, and use the cruise control when you can. and to awnser your question, I would say going 60 in a 65 is acceptable.

Answer 13

that is true driving slower will save you gas. Although if your going way under 5miles under the speed limit you have to put on your hazards and that means your moving like a sail to save a little it of gas. Silly

Answer 14

For most vehicles 50 mph is the most economical, it can be faster if you have overdrive. It is just as dangerous as speeding though to drive in relatively heavy traffic more than 5mph below the posted speed limit, even if you do keep in the slow lane.

Answer 15

Hey bro... to answer this question... dont go too slow (any more than 5mph under) or you will cause road rage and accidents.

You only save about .50 cents when you drive that slow. It isn't worth it. Drive normal. We're fighting the liberals to start drilling in America... when we do that, gas will be under a buck again.

Don't drive slow. Fight for national drilling.

Answer 16

I think minimum speed used to be 40mph,  now it might be more like 45mph.  

Either way, 95% of drivers habitually drive 5 to 10 miles OVER the speed limit so if you're going 40 or 45 miles per hour, stay all the way to the right and relax, the cars will just keep on passing you on the left-hand side.

You won't get in trouble and if anyone hits you, they will be at fault and not you.

Answer 17

When driving on the high way staying at 65 is the smartest. Your not going to slow but not going to fast your getting good gas mileage by being on the high way, but going any speed under the speed limit on the highway is not advised.

Answer 18

yes driving slower saver money and gas but you can still be pulled over i sujust only 5MPH under and depending on crime rate in the vicinity anywere from 5-7MPH over the limit and also to save gas carpool and if you can walk or ride you bike to the destination

Answer 19

Yup. The less acceleration you put on your car, the more gas you save. By staying at a constant speed (e.g. 60mph) you won't be wasting gas everytime you go slow down and then quickly increase the accerlation. That waste's a lot of gas.

Answer 20

Saving money based on speeds depends on the car.  I've had cars that get best MPG at 60 or 55 and others that got best at 75mph.

Answer 21

Really depends on the vehicle.

I like 100KmPH or 62 MPH, works with many vehicles I have owned.

I thought what you are normally looking for is the slowest RPM at you highest gear, then lock your cruise there.

Feel free to correct me if I'm wrong.