Helping to maintain track: when the light says "detected line", the camera often does not see much

Of the 39,800 seconds of actual driving with 13 models from three manufacturers, the track maintenance aid indicator shows only 47% of times when the perception of markings is degraded.

The standard track support systems (LKA) show the driver whether or not they detect ground markings. But does this light really reflect what the vehicle perceives? A team built CANDID-LKA, a method that crosses three signals: the status displayed and the torque applied to the steering wheel by the driver, read on the CAN bus, and the confidence index of a third-party vision system filming the same road.

An incomplete indicator

Applied to 39,800 seconds of driving on 13 models from three manufacturers, the analysis shows that the status reacts inconsistently to the conditions that make the lines difficult to see, and that the three brands differ greatly in their propensity to display "undetected". A latent class model estimates that the indicator only reports 47% of the seconds where perception is degraded, compared with 80% for the third-party system confidence index; In half of episodes of low confidence, it never displays "not detected".

These silences have a measurable cost: when the light indicates a detection when confidence is low and the driver does not have his hands on the steering wheel, the standard deviation of the lateral position in the next three seconds is about 60% higher than when both signals match. For authors, therefore, a "detected" light does not guarantee reliable perception.