Highway vs City MPG: Why They Differ and What It Means

The Basic Difference: Highway vs City MPG

Every new car sold in the United States comes with an EPA fuel economy label listing three numbers: city MPG, highway MPG, and combined MPG. Understanding highway vs city MPG is one of the most important things you can learn as a vehicle owner because it directly affects how much you spend on fuel every month—and it helps you choose the right car for your driving habits.

In simple terms, highway MPG measures how efficiently your car uses fuel at sustained speeds on open roads, typically between 48 and 60 miles per hour with no stops. City MPG measures efficiency under urban conditions: frequent acceleration, braking, idling at red lights, and short bursts of driving at lower speeds. For most conventional gasoline-powered vehicles, the highway number is 20–30% higher than the city number. A car rated at 30 MPG city might achieve 38–40 MPG on the highway—a substantial difference that can save hundreds of dollars per year for highway commuters.

If you are not sure what your own car achieves in each scenario, you can learn how to calculate your miles per gallon yourself or use our free MPG calculator to get an instant result based on your actual driving data.

Why Highway Driving Gets Better MPG

Highway driving is the sweet spot for internal combustion engines. Several factors work together to make sustained highway cruising far more fuel-efficient than city driving:

• Constant speed, minimal braking. Once you reach cruising speed on the highway, your engine only needs to overcome aerodynamic drag and rolling resistance. There is no energy wasted on repeated acceleration-deceleration cycles. According to the U.S. Department of Energy, maintaining a steady 55 MPH is one of the most fuel-efficient ways to drive a gasoline vehicle.
• Optimal RPM range. Modern engines are engineered to operate most efficiently between roughly 1,500 and 2,500 RPM. Highway cruising in top gear keeps the engine squarely in this efficient band. In city driving, the engine frequently operates outside this range—either idling near 700 RPM or revving higher during acceleration from stops.
• No idling. Idling consumes fuel while producing zero miles. On the highway, the engine is always propelling the vehicle forward. In city driving, a significant portion of engine runtime is spent sitting still at red lights, in traffic jams, or waiting at intersections.
• Higher gear ratios. At highway speeds, most vehicles operate in their highest gear (or the tallest ratio in a CVT), which provides the best mechanical advantage for fuel economy. City driving forces the transmission to cycle through lower gears repeatedly.
• Fewer accessory demands. While air conditioning does use more gas, highway driving allows the AC compressor to operate at a steady load rather than cycling on and off during stop-and-go traffic.

Research from Argonne National Laboratory confirms that the energy required to accelerate a 3,500-pound vehicle from 0 to 30 MPH is roughly the same as the energy needed to cruise at 30 MPH for nearly half a mile. In city driving, you repeat that acceleration penalty dozens of times on a single trip.

Why City Driving Gets Worse MPG

Stop-and-go city traffic is the single biggest factor behind lower urban fuel economy numbers.

City driving is the nemesis of fuel efficiency for conventional vehicles. Here is why your MPG drops sharply in urban conditions:

• Frequent stops and starts. Every time you brake to a stop, the kinetic energy your engine worked to build is converted into heat through the brake pads and lost entirely. Then you burn more fuel to accelerate again. This cycle repeats at every traffic light, stop sign, and traffic slowdown.
• Excessive idling. The Department of Energy estimates that idling uses roughly a quarter to a half gallon of fuel per hour, depending on engine size. In heavy city traffic, you might spend 30–40% of your drive time idling.
• Cold starts. Short city trips often mean the engine never fully reaches its optimal operating temperature. A cold engine runs a richer fuel mixture (more fuel, less air) to compensate, which can reduce fuel economy by 12% or more on trips under 5 miles, according to FuelEconomy.gov.
• Low-gear operation. City speeds of 25–35 MPH often keep the transmission in second or third gear, where the engine works harder per mile traveled compared to highway top gear.
• Aggressive driving amplifies losses. Jackrabbit starts away from green lights and hard braking at reds can reduce city fuel economy by an additional 15–30%, as FuelEconomy.gov reports.

How the EPA Tests City vs Highway MPG

The EPA fuel economy ratings that appear on every new car's window sticker come from standardized laboratory tests, not real-world driving. Understanding these tests helps explain why your actual MPG may differ from the label. The EPA uses two primary test cycles to measure city and highway fuel economy:

FTP-75: The City Test Cycle

The Federal Test Procedure 75 (FTP-75) simulates urban driving conditions. According to the EPA's testing documentation, the city cycle includes:

• A cold start phase (the engine starts from ambient temperature)
• Total distance of approximately 11 miles
• Average speed of 21.2 MPH
• Maximum speed of 56.7 MPH
• Duration of about 31 minutes
• 23 stops throughout the test
• Roughly 18% of the time spent idling

HFET: The Highway Test Cycle

The Highway Fuel Economy Test (HFET) simulates steady-speed highway driving. Its parameters include:

• A warm start (the engine is already at operating temperature)
• Total distance of approximately 10.3 miles
• Average speed of 48.3 MPH
• Maximum speed of 60 MPH
• Duration of about 12.5 minutes
• No stops during the entire test
• No idling time

Both tests are performed on a dynamometer (essentially a treadmill for cars) in a controlled laboratory environment at approximately 75 degrees Fahrenheit. The raw results are then adjusted downward by the EPA—city scores are reduced by about 10% and highway scores by about 22%—to better reflect real-world conditions. Even with these adjustments, many drivers find their actual MPG falls below the EPA numbers, especially in extreme weather or heavy traffic.

Combined MPG: What It Really Means

The "combined" MPG figure on the window sticker is not a simple average of city and highway numbers. Instead, the EPA uses a harmonic weighted average that assumes 55% city driving and 45% highway driving. The formula is:

For example, consider a car rated at 28 MPG city and 36 MPG highway. The combined rating would be calculated as:

Combined = 1 ÷ (0.55 / 28 + 0.45 / 36) = 1 ÷ (0.01964 + 0.01250) = 1 ÷ 0.03214 = 31.1 MPG

Notice that 31.1 MPG is closer to the city number (28) than the highway number (36). This is a deliberate feature of the harmonic mean—it gives more weight to the less efficient scenario. The reasoning is sound: burning more fuel per mile in the city has a proportionally greater impact on your overall fuel consumption.

If your commute is mostly highway, your real-world combined MPG will likely exceed the window sticker. If you drive primarily in the city, expect your actual combined figure to fall closer to or below the EPA city rating. You can track your own numbers over time using our fuel miles per gallon calculator to see how your actual driving pattern compares.

When City MPG Beats Highway: Hybrids and EVs

Everything discussed so far assumes a conventional gasoline powertrain. Hybrids and electric vehicles flip the script entirely—and this is one of the most fascinating aspects of the highway vs city MPG discussion.

Hybrid vehicles like the Toyota Prius, Honda Accord Hybrid, and Hyundai Ioniq Hybrid use regenerative braking to recapture kinetic energy during deceleration. Every time you slow down or stop, the electric motor acts as a generator, converting motion back into electrical energy stored in the battery. This recovered energy is then used to assist the engine during the next acceleration cycle.

In city driving, where you brake frequently, regenerative braking recovers a significant portion of energy that a conventional vehicle would waste as heat. Additionally, many hybrids can operate in electric-only mode at low speeds, shutting off the gasoline engine entirely during slow urban cruising and at stop lights. The result: hybrids often achieve higher city MPG than highway MPG.

Consider the 2025 Toyota Prius, which is rated at 57 MPG city and 56 MPG highway. Or the 2025 Hyundai Ioniq Hybrid at 55 MPG city versus 54 MPG highway. The city advantage is modest in these examples, but some plug-in hybrids show an even larger gap when operating on electric power in urban settings. This reversal of the typical pattern is a major reason why hybrids are particularly well-suited for commuters who spend most of their time in stop-and-go traffic. For a deeper dive into efficient models, see our guide to the best gas mileage cars of 2026.

Fully electric vehicles (EVs) follow the same pattern even more dramatically. Since EVs rely entirely on regenerative braking and electric motors that are inherently efficient at low speeds, their city range often exceeds their highway range. According to data from Argonne National Laboratory's transportation research, EV energy consumption increases substantially above 60 MPH due to aerodynamic drag, while city driving allows the regenerative braking system to recover up to 70% of braking energy.

City vs Highway MPG by Vehicle Type

To illustrate how the city-highway MPG gap varies across different types of vehicles, here is a comparison table using representative 2025 model-year data from FuelEconomy.gov:

As the table shows, conventional gasoline vehicles consistently achieve 29–39% better MPG on the highway than in the city. Hybrids and plug-in hybrids reverse this trend, with city efficiency matching or exceeding highway numbers. Understanding where your vehicle falls in this spectrum is key to predicting your real-world fuel costs. Want to know what counts as good gas mileage for your specific vehicle type? Our detailed guide covers the benchmarks for every category.

How to Improve Both City and Highway MPG

Regardless of whether you drive mostly in the city or on the highway, there are proven techniques to squeeze more miles out of every gallon. The Department of Energy's FuelEconomy.gov offers these evidence-based recommendations:

Tips for Better City MPG

• Anticipate traffic flow. Look ahead and coast toward red lights instead of accelerating up to them and braking hard. This alone can improve city MPG by 10–20%.
• Avoid excessive idling. If you will be stopped for more than 60 seconds (other than in traffic), turning off the engine saves fuel. Many modern vehicles have auto start-stop systems for this reason.
• Combine short trips. A warm engine is more fuel-efficient. Combining multiple errands into one trip avoids repeated cold starts that hurt city MPG.
• Use cruise control in steady traffic. On urban stretches with consistent speed limits, cruise control prevents the small accelerations and decelerations that waste fuel.

Tips for Better Highway MPG

• Slow down. Fuel economy drops rapidly above 50 MPH. Driving at 60 MPH instead of 75 MPH can improve highway MPG by 15–25%, according to the Department of Energy.
• Use cruise control. Maintaining a constant speed is more efficient than the natural speed variations of manual throttle control.
• Reduce aerodynamic drag. Remove roof racks, cargo boxes, and bike carriers when not in use. These accessories can reduce highway fuel economy by 2–25% depending on the item and your speed.
• Keep tires properly inflated. Underinflated tires increase rolling resistance, which has a larger impact at highway speeds. Check pressure monthly and inflate to the manufacturer's recommended PSI.
• Close windows at high speeds. Open windows at highway speeds create significant aerodynamic drag. Use the AC instead—at 60+ MPH, the fuel cost of air conditioning is typically less than the drag penalty of open windows.

What Reddit Drivers Say About Real-World vs EPA Numbers

Lab-tested EPA numbers are a useful starting point, but real-world driving tells a different story. Drivers across Reddit communities regularly share their actual fuel economy data, and the results are enlightening.

"I get about 34 MPG on the highway with my Civic, which is right at the EPA estimate. But in the city, I'm lucky to hit 26—the EPA says 31. Chicago stop-and-go traffic is brutal." — Discussion in r/cars

This pattern is extremely common: highway numbers tend to track EPA estimates closely, while city numbers often fall short by 10–20%. The reason is straightforward. EPA city testing uses a standardized driving pattern with moderate acceleration and predictable stops. Real urban driving involves unpredictable traffic, longer idle times, and more aggressive driving behavior.

"Switched from a regular Accord to the Hybrid and my city MPG went from 24 to 48. On the highway, the difference is smaller—maybe 36 to 44. If you do mostly city driving, a hybrid is a no-brainer." — Discussion in r/FuelEfficient

Drivers in r/FuelEfficient frequently emphasize that the biggest MPG gains come from matching your vehicle type to your primary driving scenario. A hybrid dominates in city conditions but shows a smaller advantage on long highway trips. Conversely, a diesel truck might shine on the highway but offer little advantage in stop-and-go traffic. The lesson from these real-world reports: know your driving pattern before choosing a vehicle.

To find out exactly what your car is achieving right now, fill up your tank, note the mileage, and use our MPG calculator after your next fill-up to see where you stand against the EPA estimates.

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