Is 55 mph still the most efficient speed?

The most efficient speed for electric cars is closer to 15-20 mph versus 55 mph for ordinary cars. This is because the losses at low speeds for ordinary cars has to do with the construction and inefficiency of the gas ICE. Directly to the question at hand - they also give the sources of losses over the range of speeds.
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Is 55 the most fuel efficient speed?

The Energy Saving Trust says that the most efficient speed you can travel in a car in terms of achieving the best fuel economy is 55-65mph. Any faster, though, and the fuel efficiency decreases rapidly. For example, driving at 85mph uses 40% more fuel than at 70mph (oh, and it's illegal too).
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Is 56 mph the most economical speed?

This was due to the old fuel consumption test being run at three speeds: urban, 56mph and 75mph – and 56mph was always, unsurprisingly, the most efficient of these. Typically, cars are most efficient at 45-50mph.
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Does driving 55 mph saves gas?

You can improve your gas mileage 10 – 15% by driving at 55mph rather than 65mph (104km/h). Natural Resources Canada puts the “sweet spot” for most cars, trucks, and SUVs even lower, between 30 mph (50 km/h) and 50 mph (80 km/h). Note how quickly efficiency drops after 60 mph.
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Does driving at 60 save fuel?

“We found that limiting your maximum speed to 60 MPH reduces your fuel consumption by 10%,” said Simon East, CEO of DriveGain, “but that this only adds 2 minutes to the average journey time”. “We find drivers tend to over-estimate how much quicker they will arrive when driving faster”, he added.
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The Most Efficient Driving Speed - An MPG Experiment



Why are cars most efficient at 55mph?

The most efficient speed for electric cars is closer to 15-20 mph versus 55 mph for ordinary cars. This is because the losses at low speeds for ordinary cars has to do with the construction and inefficiency of the gas ICE. Directly to the question at hand - they also give the sources of losses over the range of speeds.
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Does high speed consume more fuel?

Speeding increases fuel consumption and decreases fuel economy as a result of tire rolling resistance and air resistance. While vehicles reach optimal fuel economy at different speeds, gas mileage usually decreases rapidly at speeds above 50 miles per hour (mph).
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Does driving slower save fuel?

Going slower technically saves fuel because at high speed your engine needs to work harder to overcome drag from wind resistance, your tyres and transmission, and that drag increases exponentially the faster you go. Reduce your speed, then less power (and thus fuel) needs to be expended to overcome that drag.
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What wastes the most gas in a car?

Driving too fast.

Most American cars operate at peak efficiency—generating the most forward momentum with the least amount of fuel—between 50 and 60 miles per hour.
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Do you waste more gas with the AC on?

You might be curious about why your car uses extra fuel when the AC is on. This happens because energy is diverted from the engine to the air conditioner when it's running. This leads to more fuel usage overall. Your car has to get the energy needed to keep your AC running from somewhere.
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Does it save gas to not use AC?

Your engine warms up to an efficient temperature faster; summer grades of gasoline can have slightly more energy; and warm air causes less aerodynamic drag than cold air. However, keeping passengers comfortable in hot weather by rolling down the windows or using the air conditioning (AC) can reduce fuel economy.
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Is it better to accelerate fast or slow?

Accelerating requires more energy than steady state cruising, therefore requiring more fuel. Accelerating quickly requires more energy than accelerating slowly.
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What's the most fuel-efficient way to drive?

Fuel-efficient driving techniques
  1. Accelerate gently. The harder you accelerate the more fuel you use. ...
  2. Maintain a steady speed. When your speed dips and bursts, you use more fuel, and spend more money, than you need to. ...
  3. Anticipate traffic. ...
  4. Avoid high speeds. ...
  5. Coast to decelerate.
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Is 70mph fuel-efficient?

Fact #982: June 19, 2017 Slow Down to Save Fuel: Fuel Economy Decreases About 14% When Traveling at 70 mph Versus 60 mph. Between 40 and 50 miles per hour (mph) is the optimum cruising speed for high fuel economy in cars and light trucks according to an Oak Ridge National Laboratory study of 74 different vehicles.
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At what RPM is an engine most efficient?

Generally speaking, the faster the engine speed, the more fuel the engine is using. Between 1,300 and 1,500 RPM is the most fuel-efficient engine speed, or what some would call the “sweet spot.”
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Does coasting save fuel?

Unfortunately not – Coasting can be dangerous and coasting doesn't save fuel. If you're new to driving and are reading this, coasting is when you drive along with the clutch pushed in, or have the gear stick in neutral – or both. This disengages the engine from the wheels.
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What is the most efficient RPM to drive at?

For economy's sake, it's generally wise to remain below 3,000 rpm most of the time and to shift into the next gear before the engine gets much beyond its optimum rpm level. Too low an engine speed does nothing for your finances, so running below 1,500 isn't ordinarily a good idea.
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Does AC use gas or battery?

When you're taking full advantage of your vehicle's air conditioner on a hot day in San Francisco traffic, you may wonder, does car AC use gas? Yes: The alternator, which is powered by the engine, is what provides energy to the air conditioner. The engine runs on fuel, meaning you are using up gas when you run the AC.
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When driving over 40 mph you can increase your gas mileage B?

When driving at more than 40 mph, roll up your windows and use your air conditioner. At high speeds, open windows make your car less aerodynamic, lowering your gas mileage significantly. At speeds lower than 40 mph, you should open your windows if you're hot.
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Do you waste gas if your car is on and parked?

Saving Gas

Just 10 seconds of idling uses as much gas as restarting your car, according to the California Energy Commission Consumer Energy Center, which recommends you shut off your car when you're parked (at a drive-through business, for instance) for more than 10 seconds.
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Does accelerating quickly hurt engine?

Hard, or rapid, accelerations add stress to the engine and transmission, burning fuel more quickly. When drivers “gun it,” the vehicle sees that as a request for a power boost, burning more fuel than the driver would actually need to reach the same speed more gradually.
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Why does braking use fuel?

In an engine-braking scenario, the car would carry less speed up to the next hill, so the driver would need to accelerate, using more fuel. Coasting in neutral to gain speed should only be done safely and within applicable speed limits, of course.
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What gas burns the quickest?

Lower octane gas burns quicker than higher octane, and so require less energy to ignite. However, this also means that lower octanes burn more quickly in high pressure environments, and can have a greater tendency to knock. Knocking occurs when the gasoline is burning fast and is also under high pressure environments.
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Does rolling down the windows waste gas?

“Every car has a speed at which rolled-down windows cause so much drag as to decrease fuel economy more than a switched-on AC.
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Does turning your car on and off waste more gas?

Unless you drive a vintage, carburetor-equipped vehicle, you'll save fuel and reduce carbon dioxide emissions by turning it off. Some drivers think that idling uses less fuel than restarting, but our research has found that drivers save fuel and reduce emissions by shutting down for stops as brief as 10 seconds.
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