One model is about to treat all of these the same.
Tesla Model 3
wheelbase 2.875 m · sedan
2,035 kg
Ford Mustang Mach-E
wheelbase 2.984 m · crossover
2,336 kg
Hyundai Ioniq 5
wheelbase 2.970 m · crossover
2,084 kg
Ford F-150 Lightning
wheelbase 3.70 m · full-size pickup
3,084 kg
A 3-ton truck and a compact hatch. The baseline model is mass-independent — it predicts identical cornering for both.
The Virtual Model
KS — the driving-school model.
A rigid rod of wheelbase L, no tyre, no slip — the car goes exactly where the wheels point. Yaw rate falls straight out of geometry.
ψ̇ = (v / L) · tan(δ)a_y = v · ψ̇// no forces computed
The Scope
We give it speed and steering. It returns the lateral response.
Input · measured
What we feed in
v — speed, clamped
δ — road-wheel angle, clamped
Predicted · lateral
What it returns
x — position
y — position
ψ — heading
Measured v and δ are clamped at every integration step, so the longitudinal channel is an input, not a prediction. What's left is purely lateral — and the model's lies are all lateral, so this isolates exactly the residual we want to measure.
How V0 is Built · The File
One row per 50 Hz sample, four kinds of column.
Inputs
delta_road_rad
v_mps
a_long_mps2
accel_pedal_pct
Truth
yaw_rate_meas_rads
a_lat_meas_mps2
Ford / Hyundai only
Prediction
yaw_rate_pred_rads
a_y_pred_mps2
x_m
y_m
psi_rad
Residual
yaw_rate_resid_rads
a_y_resid_mps2
= pred − truth
The truth columns exist in sim.csv — but not in what your model is given at inference.
The Task
Predict the lateral response better than V0.
Metric 01
Yaw-rate RMSE (rad/s)
Instantaneous fidelity — how close the predicted yaw rate is to measured, every sample.
Metric 02
Cross-track-error RMSE (metres)
Where the integrated trajectory actually ends up, resampled at uniform distance.
Not redundant: a tiny persistent yaw bias is nearly invisible per-sample but compounds into hundreds of metres of drift.
The Start Line
Beat these two numbers.
V0, scored on 534 held-out segments. Everything from here is measured against them.
Yaw-rate RMSE
0.0000
rad / second
Cross-track-error RMSE
0
metres
The 254 m is the compounding-bias problem made concrete — integrate a slightly biased yaw rate over a minute of driving and the trajectory drifts off the map.