Is Driving With Autopilot More Efficient? | Tesla Model 3 Highway Test
Can Tesla’s Autopilot use less energy than a human driver on the same highway journey?
To find out, we compared two runs with our Tesla Model 3 Highland: one using Autopilot assistance whenever available, and another driving manually. Both had a target highway speed of 140 km/h, wherever permitted and safe.
We measured energy consumption, estimated range, and journey time to see how the two approaches compared.
Watch the full video below to see the test and results:
The Car and Test Conditions
For this comparison, we used our Tesla Model 3 Highland, equipped with a 60 kWh usable battery and 18-inch Michelin e-Primacy tires.
Both runs followed the same roughly 100-kilometer route, with approximately 90% of the driving taking place on the highway. We drove to the halfway point, turned around, and returned along the same route to help balance out differences in elevation and direction.
The test setup included:
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Starting battery charge: 60% for both runs
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Highway target speed: 140 km/h, wherever permitted and safe
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Outside temperature during the Autopilot run: Around 26°C
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Climate control during the Autopilot run: Set to 20°C
The journeys took place under slightly different conditions, so traffic, weather, and the speed actually maintained could all influence the results.
Test 1 - Driving With Autopilot
For the first run, we used Autopilot to manage speed, following distance, and steering within the lane whenever the system was available.
The driver supervised throughout the journey and took over when necessary, including overtaking slower traffic or navigating around obstacles. After completing those maneuvers, we re-engaged Autopilot when appropriate.
This means the results represent a journey using Autopilot assistance alongside manual interventions.
Results
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Journey time: 51 minutes
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Reported total energy consumption: 15.2 kWh
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Average energy consumption: 148.2 Wh/km
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Estimated full-battery range: Approximately 405 km
Using the recorded average consumption and our 60 kWh usable battery capacity, the estimated range came to around 405 kilometers, assuming the same consumption could be maintained across a full battery.
Test 2 - Manual Driving
For the manual comparison, we drove the same route with a target highway speed of 140 km/h whenever conditions allowed.
We overtook slower traffic when needed and accelerated back to our target speed after slower sections.
Traffic and the portions outside the highway meant we could not maintain 140 km/h throughout the journey. As with the Autopilot run, the figures cover the complete route.
Results
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Journey time: 54 minutes
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Reported total energy consumption: 15.9 kWh
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Average energy consumption: 154.8 Wh/km
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Estimated full-battery range: Approximately 388 km
The manual run used more energy and took slightly longer than the run using Autopilot assistance.
Autopilot vs Manual Driving - The Results Compared
4.3% Lower Average Consumption
Average consumption dropped from 154.8 Wh/km when driving manually to 148.2 Wh/km with Autopilot assistance.
That is a reduction of 6.6 Wh/km, or approximately 4.3% lower average consumption relative to the manual run.
Across the recorded journeys, total reported energy use was 0.7 kWh lower with Autopilot assistance.
Approximately 17 km More Estimated Range
Using the same 60 kWh usable battery capacity, estimated full-battery range increased from approximately 388 km to 405 km.
Calculated before rounding, that represents around 17 additional kilometers, or 4.5% more estimated range compared with the manual run.
These figures are projections based on average consumption. We did not drive the battery from 100% to 0% during either test.
A 3-Minute Shorter Journey
The Autopilot-assisted run took 51 minutes, compared with 54 minutes for the manual run.
So, in this comparison, the assisted journey was both more efficient and 3 minutes quicker.
However, this does not mean Autopilot will always deliver a shorter journey or lower consumption. Traffic, weather, actual driving speed, and manual interventions all affect the outcome. These two runs show what happened during our test, rather than isolating Autopilot as the sole cause of the differences.
What About Comfort?
Energy consumption and journey time are only part of the driving experience.
With Autopilot engaged, the car handles ongoing speed adjustments and steering within the lane while the driver supervises. Reducing the need for continuous steering and pedal input can make longer highway journeys feel less demanding.
The driver still needs to remain attentive and ready to take over throughout the journey.
Manual driving, meanwhile, gives you direct control over your pace, overtaking decisions, and responses to traffic. Some drivers enjoy that involvement, while others prefer having assistance during longer trips.
Is Autopilot the More Efficient Choice?
In our comparison, the Autopilot-assisted run used 0.7 kWh less energy, recorded 4.3% lower average consumption, and finished 3 minutes sooner.
That lower consumption translated into approximately 17 km more estimated full-battery range.
On these two journeys, there was no time penalty for choosing Autopilot assistance. But the difference in conditions means we cannot attribute the entire improvement to the system itself.
Beyond the numbers, comfort remains a reason to use driver assistance on the highway. Whether that appeals to you or you prefer handling the car yourself depends on how you prefer to drive.
