Lexus' next-gen safety tech steers around collisions, changes lanes automatically

We cruise the roads of Yokohama, Japan to test the Lexus Safety System+ A, the automaker's next-generation of driver aid, before it hits the road in 2018.

Antuan Goodwin Reviews Editor / Cars
Antuan Goodwin gained his automotive knowledge the old fashioned way, by turning wrenches in a driveway and picking up speeding tickets. From drivetrain tech and electrification to car audio installs and cabin tech, if it's on wheels, Antuan is knowledgeable.
Expertise Reviewing cars and car technology since 2008 focusing on electrification, driver assistance and infotainment Credentials
  • North American Car, Truck and SUV of the Year (NACTOY) Awards Juror
Antuan Goodwin
5 min read
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While on location at the 2017 Tokyo Motor Show last week, we got a look at the sort of vehicles and technologies Toyota is working on for the far future. However, I was also able to get a much closer preview of the safety technologies that will be coming to its vehicles as early as next year with a hands-on demonstration of the Lexus Safety System Plus A suite of driver aid technologies on the streets and highways around Yokohama, Japan.

Lexus Safety System Plus A (LSS+A) will debut in 2018, joining the options list of the new LS sedan and building on the current generation Lexus Safety System suite with additional and more advanced features, including Lane Tracing Assist, pre-collision steering assist, low-speed braking assist technologies and more.

Low-speed brake assist technologies

At low speeds, the rear cross traffic alert system, which detects oncoming traffic when reversing out of a parking spot, gains the ability to automatically brake to prevent an imminent collision. The system can also now detect pedestrians with its rear camera, which the automaker demonstrated with a child-sized dummy, and automatically brake to avoid them as well.

To boot, the LSS+A system adds front cross traffic alert, which detects traffic coming from either side when moving forward -- for example, when nosing out of a parking spot or blind alley where visibility may be blocked by walls or other parked vehicles.

Don't worry fake toddler, the Lexus LS' automatic braking system will keep you safe.

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Finally, the LS will gain the ability to automatically brake to prevent collisions with walls at the nose or tail of the vehicle, which will prove useful in keeping the bumpers free of scuffs in parking decks.

Between these three technologies, it should be pretty hard (but not impossible) to run into something at parking lot speeds.

Pre-collision braking with steering assist

At higher speeds, the LS features a pre-collision warning system with braking assist. So, if the system detects an inattentive driver is about to rear-end the car ahead, it flashes and sounds an alert while automatically activating the brakes to avoid or reduce the severity of a collision.

We've seen a version of this system before in Lexus' current safety suite, but LSS+A adds a new twist: it can also add steering assist to guide the vehicle around an obstruction if the stopping distance is too short. So, if a pedestrian suddenly steps into the LS' path, the system will get on the brakes and add steering assist to help juke around the human.


The rear pedestrian braking system kept the child-sized mannequin safe. We were not able to test the collision avoidance steering system.

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The collision avoidance system doesn't always add steering assistance. That only comes into play if the brakes alone won't avoid the accident -- for example if the pedestrian steps right in front of the car. The system sort of makes a judgment call at the moment and decides whether steering assist is necessary.

However, Toyota and Lexus reiterate that this is an assistance system, not an autonomous one. The steering assist is meant to get the driver's hands, which should be on the wheel at all times, moving to avoid a collision during an inattentive moment, but ultimately the human in the driver seat is responsible for avoiding an accident and not swerving into oncoming traffic.

I wasn't able to demo this particular system first hand for, ironically, safety reasons.

Lane Tracing Assist

With the move to LSS+A, the Lexus' lane keeping assist system makes a subtle evolution into the Lane Tracing Assist (LTA).

From the driver's seat, LTA feels a lot like the lane keeping system I'm used to. It uses a camera to detect the lane markers on the highway and, if the conditions are right, adds steering assist to keep the LS between the lines. Like lane keeping assist, LTA requires the driver keep their hands on the wheel and even features capacitive sensors in the wheel's rim to make sure you stay hands-on.


From the driver's seat, Lane Tracing Assist feels like the old lane keeping system, but with a more on-center feel that allows for more relaxed driving.

Antuan Goodwin/Roadshow

However, LTA has stronger "centering," working to actively keep the sedan in the middle of the lane rather than bouncing back and forth between the boundaries. The result that I was able to feel the system working and making small adjustments to the steering on the highway, but I was also able to take a more relaxed grip on the wheel while the system is active. I found it especially useful for staying centered while I getting adjusted to the reversed perspective of driving from the right-side of the car.

LTA is indicated to the driver via the LS' large head-up display with graphics representing its confident detection of the lane markers and activates alongside the adaptive cruise control system for highway use only. When the lane markers in the HUD turn blue, LTA is active.

Additionally, LTA pulls data from GPS and onboard maps to detect upcoming bends in the road and can automatically slow the vehicle if it is approaching too quickly. This is sort of a precursor to the Data Communications Module (DCM) technology that Toyota and Lexus plan to make standard across all their vehicles by the year 2020. In the future, your LS will communicate with infrastructure, other vehicles and the cloud to learn about and adapt to conditions on the road.

Lane Change Assist

Perhaps the coolest new feature demonstrated was the Lane Change Assist (LCA). This highway assistance system is able to use the power steering system to guide the LS smoothly into the next lane when activated.

Here's how it works: With the Lane Tracing Assist system active, I momentarily depressed the turn signal stalk to a half-click position. The LS then instantly checks for vehicles and oncoming traffic in the direction I want to go using the sonar blind-spot monitoring sensors. If the coast is clear, the LCA system then steers itself into to the next lane and then deactivates the turn signal.


With adaptive cruise and LTA active, Lane Change Assist is triggered by tapping the turn signal stalk in the desired direction.

Antuan Goodwin/Roadshow

Like the rest of these next-gen technologies, LCA is a hands-on system. The driver needs to be alert and touching the wheel for it to work, but I was impressed that I didn't need to make the steering inputs myself and with how smooth, yet quickly the lane change was initiated.

...and beyond

All of these new technologies (LTA, LCA and the rest) are stepping stone to the automaker's autonomous aspirations. Lexus plans to continue to evolve the technology, evolving the current suite into what it's calling "Highway Teammate" -- a Level 3 autonomous system for the highway that will be able to steer, accelerate, brake and even pass slower moving vehicles without the driver touching the wheel. Toyota and Lexus expect to hit the road with this technology by the year 2020. And, in the "early 2020s," the system will continue to expand to include surface road autonomy -- what Toyota calls "Urban Teammate" -- and start to make use of the artificial intelligence features debuted on the Concept-i series of concept cars to further boost driver comfort and safety.

In the meantime, expect the Lexus Safety System Plus A suite to make its way into the new Lexus LS' options list sometime in 2018 and start to spread throughout the Toyota/Lexus lineup from there.