What Happens Without Recalibration? It’s Worse Than You Think

Editor’s Note: This is the second part of an article entitled “‘A Matter of Millimeters’: Research Shows Why ADAS Can’t Be Overlooked,” published July 21.

The test results were sobering. An un-calibrated car was headed straight at a testing dummy, and it didn’t stop—evidence that bypassing Advanced Driver Assistance Systems (ADAS) recalibration can be deadly. A diagnostics, inspection and testing provider demonstrated this in an experiment involving an ADAS-equipped sedan and many test obstacles.

Ascential Technologies, a transportation testing and measurement company, commissioned a test from the Transportation Research Center (TRC) that simulates “real-world calibration scenarios” and measures their impact on Advanced Driver Assistance Systems (ADAS).

The experiment tested a 2024 Nissan Altima’s lane departure warning (LDW), forward collision warning (FCW), crash imminent braking (CIB), adaptive cruise control (ACC) and pedestrian automatic emergency braking (PAEB). Many of these safety functions rely on windshield-mounted cameras or sensors.

Ascential’s white paper says vehicles’ ADAS components should be recalibrated regularly as maintenance. Here, the test vehicle with its factory calibration collided with a dummy during one of the tests.

TRC first tested the car’s baseline original equipment manufacturer (OEM) calibration, then the company moved and reinstalled the vehicle’s sensors. It tested the Altima’s ADAS functions without recalibration, with “poor” recalibration in “worst-case conditions” (like in the glaring sun on a slope without following OEM instructions), and with “good” recalibration performed to OEM standards and “proper” equipment in TRC’s controlled-environment testing center.

When TRC tested the baseline OEM calibration of the Altima’s LDW, it got within an average of 8.0 inches of the line before the system’s alert sounded. The LDW alert triggered 3.6 inches away from the line after a “poor recalibration” and 7.6 inches away after a “good calibration.” Without recalibration, the system seemingly never detected the car drifting over the lines and never sent an alert.

TRC compiled data from its experiments and recorded what happened to the 2024 Nissan Altima when it wasn’t recalibrated. Chart used with permission from Ascential Technologies.

TRC found that, during FCW and CIB tests, the Altima actually performed better after recalibration than it did with factory calibration. The car stopped a minimum of 40.1 feet away from a test obstacle with its baseline OEM calibration and 46.8 feet away after “good recalibration.”  Even “poor recalibration” slightly improved the vehicle’s braking distance from factory settings. The Altima stopped 40.9 feet away from the obstacle.

Ascential’s white paper notes that the “good” minimum distance for FCW and CIB doesn’t include an unspecified outlier attributed to “inclement weather.” All calibration levels avoided a collision. Without recalibration, the systems sent alerts 13.7 feet away, causing the car to collide with the obstacle.

Without recalibrated ADAS systems, the 2024 Nissan Altima ran into the test dummy. Chart used with permission from Ascential Technologies.

The Altima’s PAEB stopped the car an average minimum of 1.5 feet away from a test dummy using baseline OEM calibration. Once again, it performed better after recalibration, stopping an average of 4.2 feet away. The car stopped an average of 4.­9 feet away after a “poor recalibration,” though the white paper notes that its stop time was “slightly delayed” and the distance was “highly variable” between tests.

When not recalibrated, the system didn’t stop the car until it collided with the dummy.

Ascential Technologies provided the video above to glassBYTEs/AGRR upon request.

“[In this experiment], good calibration more than doubled the stopping margin vs. baseline and was the only configuration with both early alerts and consistent avoidance,” the white paper says.

Ascential says vehicles need regular recalibration as part of maintenance.

Proper recalibration has also become a liability issue, according to Ascential. If a driver chooses not to recalibrate and then gets into an accident, the white paper says, “insurance might [place the blame and bill on] a shop if a recent repair was involved … Attorneys have already begun using repair records in crash cases to see if all manufacturer procedures were followed.”

With the Federal Motor Vehicle Safety Standard (FMVSS) AEB mandate taking effect in 2029, Ascential says learning how to perform proper recalibration is more important than ever.