ACTIVE AND PASSIVE SAFETY
- Unique Vehicle Dynamics Integrated Management system (VDIM)
- High- and ultra-high-tensile steel body structure realising maximum occupant protection and weight reduction
- Lexus-first Pop-Up Hood (PUH) design combining low front profile with optimum pedestrian impact protection
- 10 SRS airbags fitted as standard
Every Lexus is designed to offer the very highest levels of active and passive safety. Incorporating Lexus’ unique Vehicle Dynamics Integrated Management (VDIM) system, the new IS model range builds on the already superior safety performance of the current generation model with the addition of several, advanced new active safety features such as an Auto Location Tyre Pressure Warning System (AL-TPWS).
Within a highly rigid body structure of exceptional car-to-car impact compatibility, no less than 10 SRS airbags are fitted as standard, and a newly developed pop-up hood design allows for the lowest possible vehicle front profile while optimising pedestrian impact protection.
Auto Location Tyre Pressure Warning System (AL-TPWS)
Based on data from a sensor integrated within the tyre air valve assembly, the AL-TPWS indicates pressure values for each of the four tyres via a display located within the driver’s instrument binnacle. When low tyre pressure is detected, the display shows the air pressure of the affected tyre in amber, highlighting the figure.
With a conventional system, the warning lamp will not notify the driver of the specific tyre in question, whereas AL-TPWS clearly indicates which of the four tyres has low-pressure status.
Since sensor data is received the moment the ignition is turned on, the driver can check tyre pressures before starting off. This not only helps enhance fuel economy and tyre longevity, but also contributes to preventive safety by helping to reduce the risk of a flat tyre or similar failure.
Vehicle Dynamics Integrated Management (VDIM)
The new IS model range features Lexus’ unique, state-of-the-art Vehicle Dynamics Integrated Management (VDIM) system to enhance performance, traction control and vehicle stability.
With comprehensive status data provided by sensors throughout the vehicle, VDIM integrates the IS’s Anti-Lock Brakes (ABS), Electronic Brakeforce Distribution (EBD), Traction Control (TRC) and Vehicle Stability Control (VSC) active safety systems with the Electronic Power Steering (EPS) or, in the case of the F SPORT, Variable Gear Ratio Steering (VGRS).
By the application of integrated control of all the elements related to vehicle movement, including motor torque, brakes and steering, VDIM not only optimises the activation of braking, stability and traction control systems, but is also able to further improve the overall kinetic performance of the vehicle.
Moreover, whereas conventional active safety systems are only activated immediately after a limit of the vehicle’s dynamic envelope has been reached, VDIM activates control before that limit is realised. As a result, the limits of the vehicle’s dynamic threshold have been expanded, while offering smoother vehicle behaviour at this threshold through less obtrusive intervention and, hence, a more pleasurable drive.
When braking in a corner, for example, a loss of rear tyre grip may result in oversteer. Through the EBD function, the use of linear brake actuators makes it possible to begin control before the vehicle’s limit has been reached. The VDIM system apportions the appropriate braking force to each wheel, ensuring continued vehicle stability by pre-emptively restraining the spinning tendency, while contributing to superior braking performance.
Under even stronger braking in a corner, front wheel lock-up and loss of grip may result in understeer. By once again independently controlling the braking force to all four wheels via the EBD system, VDIM helps to prevent front wheel lock-up and regain vehicle balance, offering seamless control until the conventional ABS and VSC functions take over.
Moreover, via the EPS or VGRS actuator, VDIM will augment VSC operation by providing steering assistance to reduce torque steer under braking on surfaces of varying grip, as well as introducing steering torque assistance in both understeer and oversteer conditions, helping the driver to optimise the front wheel steering angle and maintain vehicle stability with minimum input.