Following up on the report of the Ioniq 5, CR’s team of auto experts tested the brake-light behavior on each of the 24 EVs in our own fleet (all purchased for our auto-test program) to see how widespread this issue might be across brands and models.
CR’s engineers measured how quickly each car slowed down when using the vehicles’ one-pedal-driving regenerative-braking modes, and observed at what rate of deceleration each vehicle’s brake lights came on. “On average, we found that the brake lights of most EVs in our fleet illuminate when the regenerative braking system is slowing the car at about 0.1g (g-force), which could be described as a slight but noticeable amount of braking force,” says Alex Knizek, CR’s manager of auto testing and insights. “We think that is a level of deceleration that warrants informing other drivers via the car’s brake lights.”
While most of the EVs in CR’s fleet did illuminate their brake lights appropriately during aggressive regenerative braking, several of them did not, even when deceleration levels were considered more aggressive. Those include:
- 2022 Hyundai Ioniq 5 SEL AWD
- 2023 Genesis GV60 Advanced
- 2023 Genesis Electrified GV70
- 2022 Kia EV6 Wind AWD
- 2023 Kia Niro EV Wind
This potentially dangerous issue doesn’t exist on CR’s 2023 Hyundai Ioniq 6 SEL AWD test vehicle, as it operated consistently with proper brake-light illumination when slowing the vehicle in its i-Pedal mode, even if the driver maintained some pressure on the accelerator pedal.
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CR contacted Hyundai and Genesis, as well as Kia separately, to find out whether the companies are aware of the potential safety risk, and whether the problem could be rectified by an over-the-air update or a recall. Miles Johnson, Hyundai senior manager for quality, service, and technology public relations sent the following statement, which he said covered the Hyundai, Kia, and Genesis brands: “Hyundai is aware of the customer concerns regarding EV brake light illumination. Hyundai engineering teams are investigating and reviewing our EV braking strategies. All Hyundai Motor Group electric vehicles meet the FMVSS No. 108 standard that regulates all automotive lighting. Hyundai is committed to vehicle safety and the well-being of our customers.”
Kia’s James Hope responded similarly: “Kia America is aware of comments concerning i-PEDAL brake light logic on the 2023 Niro EV and 2022/2023 EV6 (excluding GT trim) and is evaluating the matter. Kia places a priority on vehicle safety, and all Kia vehicles sold in the United States meet or exceed all federal motor vehicle safety standards.”
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In the process of our EV brake-light testing, we uncovered another potential safety issue with some electric Mercedes-Benz models: When the Strong Recuperation regenerative-braking mode is engaged (which is Mercedes’ term for its one-pedal driving), the brake lights on the vehicles we tested turn off as the vehicle comes to a complete stop. Initially, after the driver steps off the accelerator pedal in Strong Recuperation mode, the brake lights illuminate when deceleration reaches about 0.15g. Then, as the speed drops down to about 5 mph—and as the vehicle reduces its deceleration rate to smooth out the stop—the brake lights suddenly turn off. They remain off for more than 15 seconds, which is long after the vehicle has stopped. They illuminate again automatically after about 15 seconds.
The vehicles that exhibited this behavior, all purchased as part of CR’s regular test program, are:
- 2022 Mercedes-Benz EQS 580 4Matic
- 2023 Mercedes-Benz EQS SUV 450 4Matic
- 2023 Mercedes-Benz EQE SUV 350 4Matic
- 2023 Mercedes-Benz EQE 350 4Matic sedan
insideevs.com
