Automotive safety has grown up in layers. Passive safety, things like seatbelts and airbags, reduces harm once a crash is already happening. Active safety, such as anti-lock braking and electronic stability control, steps in while you drive to help prevent the crash in the first place. The newest layer, predictive safety, uses driver assistance and automated driving to remove the mistake before it occurs. Electrification adds one more dimension, because the battery itself now needs surveillance.
Behind every one of these layers sits sensing: a small device measuring pressure, acceleration or angular rate and passing it to a control unit that decides what to do. This article looks at where that sensing is advancing across the vehicle, from the tire and crash detection to vehicle stability and the battery in an electric car.
Safety starts at the tire
Tires are easy to overlook, but an under-inflated tire handles worse, takes longer to stop and is more likely to fail at speed. On an electric car it also cuts range. That is why tire-pressure monitoring is mandated in many markets and has become one of the most widespread passive-safety features on the road.
The job is harder than it sounds. A sensor sits inside each tire, measuring pressure and temperature and sending the reading to the vehicle by radio. It has to run for years on a small battery, so it spends most of its life asleep, and an accelerometer wakes it once the wheel starts turning and helps the system work out which wheel it is fitted to.
ST’s NTM88 family covers this across vehicle types, from passenger cars and two-wheelers to light trucks, buses, heavy trucks and trailers, and even agricultural equipment, with pressure ranges up to around 1500 kPa. Each device packs the pressure sensor, an 8-bit microcontroller with a dedicated TPMS firmware library, a dual-axis accelerometer for wake-up and localization, and the radio interfaces into a 4 by 4 mm package. The sensors are AEC-Q100 qualified, rated to +125 °C, draw as little as 180 nA in sleep, and are in mass production.
Passive safety: airbags and restraints
Passive safety is about limiting the harm once a crash can no longer be avoided, and that depends on recognizing the impact fast enough to act on it. Small inertial sensors placed around the vehicle sense the sharp deceleration of a collision and signal the airbag control unit to fire the airbags and tension the seatbelts at the right instant. The same kind of sensing supports pedestrian protection, where the system responds to an impact at the front of the car, and rollover detection, where it senses the vehicle beginning to tip. ST’s crash-detection inertial sensors, including the NXLS95322AES and NXLS95422AES, are built for these roles.
Active safety keeps the car stable
Active safety works while the car is moving. Anti-lock braking came first; electronic stability control (ESC) built on it and is now standard in many regions. ESC and traction control track how the vehicle is behaving, its rotation and acceleration, its wheel speeds and steering input, and if they sense the car starting to slide or a wheel losing grip, they brake individual wheels or trim engine torque to bring it back into line. Rollover prevention works the same way.
All of this depends on inertial sensing that stays accurate in a demanding chassis environment, close to heat and vibration, and that is dependable enough to sit inside a safety function. ST’s combo sensors family targets these vehicle-stability and traction-control roles, the kind of sensing that lets a stability system read the vehicle’s motion precisely enough to step in at the right moment.
A new frontier: protecting the EV battery
Electrification brings a safety concern that combustion cars never had: thermal runaway, where a failing lithium-ion cell overheats and can set off nearby cells. One of the earliest physical warning signs is a change in pressure inside the battery pack, which can appear before the temperature climbs far. Detecting it early buys time to warn the driver or take protective action.
A battery pressure monitoring sensor watches for those abnormal changes. ST’s NBP8 family does the work at the edge. Each integrates an 8-bit microcontroller with firmware and user-selectable detection algorithms, a fixed threshold, a change in pressure, or a rate of change over time, so the sensor itself can flag an anomaly and let the rest of the system stay powered down until something happens. The parts cover an absolute pressure range of 40 to 250 kPa with accuracy within about 1.2%, are AEC-Q100 qualified and rated to +125 °C.
Toward predictive safety
Starting with the safety of the tire, the newest layer, predictive safety aims to prevent the mistake altogether, through driver assistance and automated driving. Part of that is active prevention: monitoring the driver, and combining that with data from the navigation, active-safety and tire systems so the car can respond to a developing risk early. It also relies on fusing several sensing types, cameras, radar, lidar, satellite positioning and inertial units, into a single picture of the car and its surroundings. The same forward-looking approach reaches the powertrain, where a vibration sensor on an electric vehicle’s traction inverter can catch the early signs of wear and trigger predictive maintenance before a fault develops. It is a large field, but the underlying direction is the same as everywhere else: sensing that is more accurate, and closer to the source, makes the whole system safer.
A common thread
Across all these layers the pattern repeats. Safety keeps moving toward smaller, smarter sensors that measure a physical signal, whether pressure, acceleration or angular rate, and act on it early. Tire pressure, crash detection, vehicle stability and battery health are all current examples, and more will follow as vehicles electrify and automate.
Explore ST’s automotive MEMS and sensors portfolio to see the full range across these safety functions.