What Are They & How Do They Work?

Advanced driver assistance systems have gained in popularity over the past decade or so, with systems like adaptive cruise control and automatic emergency braking becoming fixtures in modern cars. Around 60% of all light vehicles sold in the U.S. in 2023 sported some form of adaptive cruise control, for example, up from around 30% just five years prior, Wards Intelligence notes. It’s a huge market, too, worth $14 billion as of 2022, according to Fortune Business Insights, and showing little to no signs of slowing down any time soon.

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Many of the world’s best carmakers have their takes on driver assistance technology, and Subaru is no exception. Subaru’s Eyesight — not to be confused with the company’s infotainment system, Subaru Starlink — has been available in all Japanese-market automatic Subarus since 2008, with the U.S.-market debut coming in 2013. Eyesight was an automatic-only feature for a long time, but the company announced that its manual sports cars would also get Eyesight in 2024. 

Eyesight utilizes two front-facing cameras placed on either side of the rearview mirror, which scan the road ahead and allow the system to make any necessary interventions to avoid crashes, maintain distance during cruise control, or steer the driver away from crossing lane markers. These features work alongside other non-Eyesight safety tech such as blind-spot detection, automatic reverse braking, and rear cross-traffic alerts. But we’re not covering the latter features here, though: this is all about Eyesight. Let’s get started.

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Adaptive cruise control was one of the three Eyesight-powered safety features available when the carmaker debuted it in the U.S. market Legacy and Outback in 2013. The initial version of Subaru’s adaptive cruise control worked similarly to most other adaptive cruise control systems available: It used the Eyesight cameras to monitor the car in front and accelerate or decelerate to maintain a target speed or distance — the latter selectable from several preset distances. The system worked up to 87 mph and was allowed to bring the vehicle to a complete stop if necessary, so it worked in stop-and-go traffic.

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Subaru updated its adaptive cruise control in 2020 and introduced a new name: advanced adaptive cruise control. The primary addition as seen in cars like the 2020 Subaru Outback was the presence of lane centering. Lane centering — not to be confused with Eyesight’s separate lane departure features — ensures that the car stays in the middle of the lane during cruise control. It does this by monitoring the lane markings and gently nudging the vehicle left or right to avoid coming too close to the lane markings, even when taking curves. It’s not quite on par with level 2 autonomous driving systems like Hyundai’s HDA2 and HDA3, but it’s something.

Subaru has kept its cruise control feature pretty much the same since that 2020 update. However, the company claims that the technology has benefited from the wider camera field of view introduced in Eyesight 4.0, which debuted on 2023 vehicles like the Forester.

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Eyesight’s lane-monitoring features debuted in the U.S. market alongside the initial version of adaptive cruise control for the 2013 Legacy and Outback. As with cruise control, the earliest version of the system was relatively basic, mostly focusing on monitoring lane markings and alerting the driver when they approached them too closely without using a turn signal — making the arguably valid assumption that anybody swaying or moving outside of their lane without signaling wasn’t doing it intentionally.

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Subaru updated the system in 2019 with a new feature called Lane Keep Assist. As the name suggests, the new functionality allowed Eyesight to do more than just alert the driver if they began to drift or leave a lane without signaling. Lane Keep Assist allowed the car to automatically correct itself if the driver failed to address lane sway or departure quickly enough, steering the vehicle back into the center of the lane. 

Interestingly, Subaru notes that the system’s control and timing may not mesh with all driving styles and that users shouldn’t use the lane keep feature if the assist goes against the driver’s preferences or habits. Despite that, we think it’s worth getting used to lane assist, especially when driving on the highway or other roads with clear markers.

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The third Eyesight feature that debuted in 2013 is the pre-collision braking feature. As the name suggests, pre-collision braking tries to mitigate or avoid accidents by alerting the driver to obstacles up ahead and automatically applying the brakes to slow the car down — if the driver doesn’t brake quickly enough.

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Pre-collision braking is a three-step system: first, it sounds a warning if it determines the car might crash into the car (or object) ahead. If the danger persists, the dash lights up and the car starts braking. If a collision is still imminent, Eyesight enables fully and applies the brakes to bring the car to a stop. That said, pre-collision braking isn’t a replacement for the driver: Subaru’s manual indicates that the system may not be able to avoid a collision if the speed difference between the car and the object is greater than 30 mph (for another vehicle) or 21 mph (for a pedestrian). That’s likely where the new emergency steering comes into play, but we’ll discuss that later.

It’s worth noting that data seems to confirm the effectiveness of this particular aspect of Subaru’s safety technology. The IIHS has noted that Subaru’s Eyesight technology — specifically its ability to brake automatically — has led to a reduction in injury claims amongst pedestrians. Accidents involving Eyesight-equipped Subarus had 35% fewer bodily injury claims, IIHS notes, compared to those Subarus without Eyesight.

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Like pre-collision braking, Eyesight’s pre-collision throttle management is another feature that focuses on helping the driver avoid frontal impacts. But it has a few crucial differences, the most obvious being how it slows the car down: instead of applying the brakes, the system reduces engine power. Pre-collision throttle management primarily works at low speeds or when stationary.

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It kicks in when the car in front accelerates and then suddenly stops, for example, by emitting a warning and immediately reducing engine output. This reduction should, hopefully, slow the car down enough for a driver to apply the brakes. But this feature also works when parked: if the driver mistakenly puts the car into drive when in front of a stationary obstacle, pre-collision throttle management steps in and prevents the car from accelerating.

According to Subaru’s manual, the system essentially checks if the driver is depressing the throttle more than it deems necessary in any given situation. If it does, then it steps in. It’s worth noting that the feature cuts out when it sees steering input that it interprets as the driver taking evasive action.

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Emergency steering is the latest addition to Subaru’s suite of Eyesight safety features, introduced in vehicles like the 2023 Subaru Outback. Like the other Eyesight features, automatic emergency steering works precisely how you’d expect based on the name: It can automatically swerve to avoid collisions on the road.

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Eyesight first tries to alert the driver and slow the car down via braking, as we discussed in the pre-collision braking section. But if that isn’t enough, then the system can automatically take evasive action to avoid a crash, turning to ensure that the car doesn’t run into the obstacle in front. However, it doesn’t do this blindly, of course, and Eyesight performs a few checks before it allows the automatic emergency steering to take over.

Automatic emergency steering checks the lane markings to see whether there’s enough space to avoid a crash without leaving the current lane. It simultaneously checks the data from Subaru’s blind-spot detection and rear traffic alert safety features to ensure there isn’t any oncoming traffic. If the coast is clear, the system engages and steers automatically to avoid the obstacle in front — provided that the pre-collision braking was enough to slow the car down, that is. Subaru states that the system is designed to avoid collisions below 50 mph; any higher, and you’re likely relying on Subaru’s great crash protection to keep you safe from harm.

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