A strong cabin keeps its shape in a crash. The people inside it still move.

Part 1 of this series covered the safety cage and the high-strength steel that keep the cabin intact during an impact. A cabin that holds its shape is the first requirement. The second is control over how the passenger moves inside it.

In a frontal impact, the vehicle stops in a fraction of a second. The passenger's body keeps moving forward at the original speed until something stops it. The restraint system decides what stops it, and how much force the body takes in the process.

In most Micro-EVs, that system is a basic seat belt and nothing more. Airbags are rare in this category, and so is crash testing. The ASTRAUX AL7 series is the only vehicle in its class with airbags as standard equipment. We crash test it to verify how the full system performs.

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The cage from Part 1 also decides whether the systems in this post can do their job. Airbags and seat belts are designed to work from a fixed position. If the cabin compresses, they move with it and can no longer protect the passenger correctly. The cage keeps the cabin intact, so they stay where they need to be. This post covers what they do once an impact starts: the airbags, and the seat belt system that works with them.

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Impact

Airbags

Sensors in the AL7 series detect a collision the moment it happens. When the force passes a set level, the system inflates the airbag in milliseconds. The airbag is fully open before the passenger's head and upper body can reach the steering wheel or the dashboard.

The airbag gives the head and chest a wide, soft surface to stop against. Force spreads across a larger area of the body, and the head slows more gradually. Without an airbag, a hard surface inside the cabin absorbs that movement instead.

Safety tests are rarely seen in the Micro-EV category. ASTRAUX chose to test. The simulation below shows what happens to the vehicle and the passenger inside it during a frontal impact.

Watch the full crash test video on Instagram →

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Restraint

Pretensioner and Load-Limiter Seat Belt

A standard seat belt works at one fixed setting. It locks when the vehicle stops suddenly, and it does not adjust to the passenger or to the force of the impact. This creates 2 problems. If the belt sits loose, from clothing, seat position, or the way it crosses the body, the slack lets the body travel forward before the belt can hold it. If the impact is strong, the belt holds at full strength and can press too hard on the chest. The pretensioner and the load limiter each solve one of these problems.

The pretensioner removes that slack. At the moment of impact, it pulls the belt tight in milliseconds and holds the passenger against the seat before the body starts to move. This prevents the most serious risk in a frontal impact: the head and chest traveling forward and hitting the steering wheel, the dashboard, or the windshield. This is the first stage: instant restraint.

The load limiter solves the second problem. Once the belt holds the passenger, the force it puts on the chest rises very quickly. If the belt keeps holding at full strength, that force alone can break ribs or injure the organs behind them. When the force reaches a set level, the load limiter lets the belt release a small, controlled length of webbing. The body stays held, and the chest no longer takes the full load. This is the second stage: controlled protection.

The 2 systems work in sequence. The pretensioner holds the passenger in the correct position. The load limiter lets the upper body move forward into the airbag at a controlled rate, and the airbag protects the head and chest. Around all of it, the cage keeps the cabin space intact. The whole sequence takes less than a second.

In a full passenger car, all of this is standard. In the Micro-EV category, it is almost absent. Large automakers sell vehicles in this category too, and most of them still build to the legal minimum: a basic belt, no airbag, and no published crash test. ASTRAUX EV was built to a different standard. A vehicle this size should protect its passengers the way a full car does, and we will keep showing that standard in public, one component at a time.