The new fifth-generation Lexus LS, which launches in fall 2017 in some markets and replaces a car introduced in Japan way back in 2006, continues the previous model’s tradition of a smooth ride with exceptional quietness and comfort. However, the new GA-L platform on which it is based is said to place more emphasis on driving thrills, and the car’s bold new styling envelopes some advanced new technologies. They include an all-new twin-turbo V6 with 415 hp (309 kW), ten-speed automatic transmission, and an all-new available Lexus advanced safety system.

It is with that last element the engineers of the new Lexus LS expect will provide world-leading safety performance. The advanced safety system is in essence two systems that combine a redesigned Lexus Safety System + and the new Lexus Safety System +A. In a sneak peek for media on June 26th, Lexus previewed the features of these systems.

The foundation is the well-established package Lexus Safety System +, which is based on the brand’s first stab at an Integrated Safety Management Concept approach that aimed for the coordination of individual safety technologies and systems in pursuit of greater driver support in varied driving situations. Now added to this is the Lexus Safety System +A, which provides advanced pre-collision support and driving assistance for cars intended for markets in Japan, North America, and Europe. Support was designed to be clear and intuitive, with information ranging from status notifications to information on vehicle behavior during safety feature operation via a large headup display (HUD) and a multi-information display.


New technologies of +A

Added to improvements in Lexus Safety System + features, which include Pre-Collision System (PCS), Lane Departure Alert (LDA), and Dynamic Radar Cruise Control, the main additions of the +A system are:

  • Active Steering Assist, claimed as a world-first technology (as of June 2017 based on a Lexus survey) that helps prevent collisions that cannot be avoided through automatic braking alone.
  • Front Cross Traffic Alert (FCTA), which is designed to warn the driver of the possibility of head-on collisions at intersections.
  • Lexus CoDrive, which assists the driver in maintaining in-lane driving or in changing lanes.

In addition to conventional PCS—which supports collision prevention and damage reduction through alerts, Pre-collision Brake Assist, and Pre-collision Braking—the new LS is equipped with Pedestrian Alert, a reportedly world-first technology that specifies the direction of the presence of a pedestrian, and Active Steering Assist, which can automatically control steering and braking. With Pedestrian Alert, if there is the possibility of collision, the direction of the pedestrian's presence is shown in an animation via the car’s large color HUD. Active Steering Assist determines when there is a high possibility of collision with a pedestrian in the lane of travel or with a continuous structure such as a guardrail. If the system also determines that it is difficult to avoid a collision with brake control alone, the system assists in collision prevention or damage reduction through automatic steering control in addition to activating an alert and applying the brakes.

Lexus CoDrive adds Lane Change Assist (LCA) to the basic functions of Dynamic Radar Cruise Control and Lane Tracing Assist (LTA) to provide steering support in line with the intentions of the driver and lane-changing support on highways. CoDrive largely decreases driver burden by providing driving support on roads with many curves or in traffic jams, and it coordinates with the HUD and multi-information display to clearly notify the driver of the state of support provided.

Lane Tracing Assist provides lane-keeping support when Adaptive Cruise Control is in operation. In addition to lane-line detection by camera, path tracing of the vehicle ahead enables assistance when lane lines cannot be recognized such as in low-speed driving in congestion when there is little distance to the preceding vehicle. If the speed entering a curve is too fast (based on navigation data), the driver is alerted by HUD and multi-information display and the vehicle is automatically slowed down. LCA monitors driver use of the turn signal as a cue to support lane changes; it scans the surrounding road environment and controls steering as well as acceleration and deceleration.

If the LTA detects insufficient driver control on a motor-vehicle-only roadway, Driver Emergency Stop Assist provides audio and visual alerts and gentle deceleration to a stop. It then activates the vehicle's hazard lamps and horn to help prevent injury or reduce vehicle damage while slowing and eventually stopping the vehicle within its lane. After stopping, it unlocks doors and activates an automatic connection for a rescue request.

The Two-stage Adaptive High-beam System, with eight LED lights at the top and 16 below (on each side), has separate on/off control of each row of LEDs to enable finer control of light strength and distance compared to the existing LED-based AHS. This allows higher frequency of high-beam driving without blinding preceding or oncoming vehicles, improving nighttime visibility.

Lexus claims that FCTA is the first such system meant to detect forward cross-traffic vehicles at intersections that use radar to alert drivers of the direction from which a vehicle is approaching. If the vehicle proceeds regardless of the presence of an approaching vehicle, alerts are displayed in the HUD and warnings are also issued by a buzzer and the LS's multi-information display.

Finally, Road Sign Assist (RSA) uses a camera and navigation maps and then displays information in the LS's HUD and multi-information display.


Further evolution of +

Lexus has further evolved the performance of the Pre-Collision System (PCS), Lane Departure Alert (LDA), and Dynamic Radar Cruise Control in the active safety Lexus Safety System +.

PCS detects pedestrians and vehicles ahead using millimeter-wave radar and a stereo camera. It supports collision prevention and damage mitigation with an alert, Pre-collision Brake Assist, and Pre-collision Braking. The improved system can detect bicyclists and nighttime pedestrians and has improved deceleration performance during automatic braking. For example, it can decelerate the vehicle by as much as 60 km/h (37 mph) when a pedestrian is detected, thus improving its collision-prevention performance.

LDA is now also capable of detecting the boundaries between asphalt and elements such as grass, dirt, and curbs through advances in recognition capability. Thus, it can now perform its functions of alerting the driver and operating the steering wheel even on roads that do not have lines.

For the Dynamic Radar Cruise Control, basic recognition performance is improved by using a newly developed millimeter-wave radar and a camera with a wider forward recognition range, also providing smoother acceleration and deceleration.


Supporting active technologies

Low-speed braking support systems have been integrated into a single package, the primary objective of which is to reduce damage from accidents when parking. Added to the already-in-production Intelligent Clearance Sonar (ICS) and Rear Cross Traffic Auto Brake (RCTAB) is a claimed world's first rear pedestrian support brake, which detects pedestrians using a rear camera; in the case of a possible collision, it helps minimize damages by using alerts and brake control.

Side-clearance and cornering view functions have been added to the Panoramic View Monitor. Side-clearance view produces an image on the LS's 12.3-in display monitor of the area in front of the car as if it were seen from an elevated point at the rear of the car. When side clearance view is in operation, cornering view automatically produces an image of the vehicle as viewed from the rear at an angle in line with driving operation during cornering.

The Digital Rear-View Mirror shows the image captured by a rear camera on a built-in display in the rear-view mirror. It produces an image without obstructions (such as the heads of rear-seat passengers) and contributes to enhanced visibility at night and in rainy weather. Operation of a lever switches the display between optical and digital mirror modes.