Both road-load models, side by side
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2-cycle range = usable battery / energy used per mile on the cycle x the adjustment factor (0.7 unless the maker's own 5-cycle factor is on file), combined = 55% city, 45% highway, harmonic. That is the arithmetic behind a window-sticker label. A maker estimate (*) is not an EPA label.
Each bar adds up to the battery energy per mile. Braking is assumed fully regenerative; regen losses are the drivetrain and battery round-trip efficiencies on the way back in.
What the car has to push against at a steady speed: the two road-load models for this vehicle, and the EPA 2-cycle schedules' speed range shaded.
Every vehicle through the same two cycles
Model 2-cycle combined range, coast-down and aero where the data allows each, against the published figure. Computed live in your browser from the same data files the road trip tool uses. * = maker estimate, not an EPA label.
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What you are looking at
UDDS (Urban Dynamometer Driving Schedule) is the EPA city test: 1,369 seconds, 7.45 miles, average 19.6 mph with 17 stops, top speed 56.7 mph. HWFET (Highway Fuel Economy Test) is the highway test: 765 seconds, 10.26 miles, average 48.3 mph, top speed 59.9 mph, no stops in between. Both are second by second speed targets that every car follows on a dynamometer. The schedules are published by the EPA (source).
This page drives the selected vehicle through both schedules with the same physics the road trip tool uses, one second at a time: inertial force from mass and acceleration, road load from either the EPA coast-down coefficients or the aerodynamic model, wheel power, then battery power through the drivetrain efficiency, with regenerative braking credited through the drivetrain and battery round-trip efficiencies. The arithmetic is a direct port of the model workbook's drive cycle tabs; the two agree to four decimal places, which the shipped test suite checks on every build.
Coast-down vs aero. The EPA test does not measure drag on the road. Each manufacturer measures a coast-down and submits three coefficients (A, B, C) that the dynamometer reproduces. That is the road load the label was made with, so it is the better model whenever it exists. The aero model (Cd x frontal area for air, Crr x weight for the tires) is the physics estimate used for vehicles with no certification data yet.
Conditions. EPA reference: 68 °F, 862 ft, dry air, no wind, no climate control, 250 W accessory load. The road trip tool assumes 650 W of accessories instead, which is why its steady-speed numbers run a little below what you see here.