8. Basic Mechanics, Safety Elements and Accidents

Introduction: the vehicle, the driver and the emergency

This chapter closes the training block by bringing together three fundamental pillars of road safety: basic knowledge of vehicle mechanics, the systems that protect the occupants, and how to act correctly in the event of an accident. Good maintenance reduces the risk of breakdown and incident, safety elements cushion the consequences when something fails, and the PAS protocol allows the human response to save lives instead of causing new victims.

Statistics confirm that the human factor is the main cause of accidents, but technical improvements in design and manufacturing have been reducing the influence of the vehicle. Even so, driving a poorly maintained car or not using its safety systems correctly multiplies the probability and severity of injuries, especially at high speeds.

1. Basic vehicle mechanics

The major systems

Engine: generates the energy needed to move the vehicle. An engine failure prevents safe driving.
Braking system: allows you to reduce speed and stop the car. The service brake (pedal) acts on all four wheels and is the main one. The parking brake (handbrake) is used only to immobilise the vehicle when stopped, never while moving.
Tyres: they are the only point of contact with the asphalt. Grip, braking and stability depend on them.
Steering: allows you to control the trajectory. A failure causes loss of control.
Suspension and shock absorption: absorb road irregularities and keep the tyres in contact with the ground, ensuring stability and grip.

Tyres: the key figure of 1.6 mm

The tyre is probably the most frequently asked element in the exam. It must be replaced when the tread depth is less than 1.6 mm, the legal limit. In addition, it cannot show blisters, bulges, abnormal deformations or breaks: a bulge indicates an imminent risk of blowout.

The correct pressure is always the one indicated by the vehicle manufacturer, and it must be checked frequently, cold and before any long trip. Both low and excessive pressure are dangerous:

Low pressure: increases friction, fuel consumption and wear; overheats the tyre.
Excessive pressure: never increase the pressure above the recommended level, as it reduces the contact surface and decreases grip, especially in wet conditions.
Unequal pressures on the same axle: deflect the vehicle towards the side with less pressure and cause irregular braking.

Other important aspects: tyres hardened by ageing lose grip and can cause skidding; winter tyres wear out faster in heat, so they should be replaced as temperatures rise; and the temporary use wheel (space-saver) requires you to respect the kilometres and maximum speed indicated by the manufacturer. The spare wheel can be replaced by an alternative system that guarantees mobility.

Brakes, engine and other components

If the brakes get wet they may temporarily lose effectiveness; if in wet conditions you have to fully press the pedal to stop the car, suspect a system failure. Braking effectiveness depends directly on the tyres' grip on the ground: in good condition they shorten the braking distance.

Other vehicle elements worth knowing:

Engine oil: checked with the dipstick. Oil that is too fluid when hot does not lubricate the parts correctly. Changing the oil periodically reduces wear and extends engine life.
Coolant: cools the engine and prevents overheating.
Air filter: cleans the air mixed with the fuel and protects the engine.
Cabin filter: should be replaced, especially at the beginning of spring.
Silencer and exhaust pipe: the silencer reduces the noise of engine explosions. It is forbidden to drive with a damaged silencer due to noise pollution.
Wiper blades: continuous heat hardens and cracks their rubber. Check them periodically and change them when damaged.
Windscreen washer: regularly check the fluid level.
Black smoke from the exhaust: indicates poor combustion and requires vehicle inspection. Increased fuel consumption requires checking the ignition and fuel supply circuits.

Preventive maintenance

Preventive maintenance includes checking the adjustment and operation of the lighting, fluid levels and the general condition of the vehicle. Tyres, brakes and shock absorbers require more frequent inspection than the rest of the components. After summer it is advisable to check the car, especially if it has been near the sea due to salt corrosion. Good maintenance reduces the vehicle's risk factor in driving.

When refuelling, it is mandatory to keep the engine, lights, electrical systems (including the radio) and mobile phone switched off.

2. Active safety: avoiding the accident

Active safety encompasses all systems that act before the accident to prevent it from occurring. It includes the brakes, tyres, steering, suspension and lighting, together with advanced electronic devices:

ABS (anti-lock braking system): prevents the wheels from locking during hard braking, allowing you to retain steering control during braking.
ESP (stability control): corrects the trajectory when the vehicle tends to skid.
ADAS systems: advanced driving aids, now mandatory in new vehicles, which assist the driver with emergency braking, lane keeping, fatigue detection, etc.

Good shock absorption prevents accidents by keeping the tyres on the asphalt; shock absorbers in poor condition cause excessive leaning in curves and loss of control.

3. Passive safety: reducing the damage

Passive safety groups together the systems that act during or after the impact to reduce the consequences. Its essential elements are the seat belt, airbags, headrests and the bodywork itself, designed to deform and absorb energy while protecting the cabin.

Seat belt

It is the most effective passive system for preventing serious injuries at any speed. All occupants of the car must wear it correctly fastened, including pregnant women. Not wearing it doubles the risk of death in all seats of the vehicle. It can only be dispensed with during reversing or parking manoeuvres.

For it to work correctly it must:

Be well stretched, without slack, without twists and adjusted to the body (neither too tight nor too loose).
Rest the lap belt on the hip bones, never on the abdomen.
Avoid using cushions on the seat, which alter posture and reduce its effectiveness.

The seat belt prevents the so-called submarine effect, which occurs when the body slides under the belt, especially if the lap band is too high. After an accident the belt must be checked or replaced, as the weave and the anchorages may have been damaged.

Airbag

The airbag complements the seat belt, never replaces it. Without a seat belt it can cause serious injuries: both systems always work together. Its mission includes protecting the face from windscreen glass fragments. If you install a rear-facing child seat in the front passenger seat, you must deactivate the front airbag compulsorily.

Headrest

Protects the cervical area in case of collision, especially from the dreaded whiplash, which causes muscle contraction, loss of neck mobility and vertigo. It must be adjusted for each occupant, including those in the rear seats:

The central part of the headrest must be at eye level.
The distance to the head must be as small as possible and never greater than 4 cm.

Without the seat belt fastened, neither the airbag nor the headrest can fulfil their protective function.

Motorcyclist's equipment

The motorcyclist is directly exposed, so protective clothing is essential:

Helmet: it only protects if the strap is correctly fastened. Choose one with good ventilation to prevent the visor from fogging up. The driver is responsible for ensuring that their passenger wears it.
Suit: must resist impacts and abrasion in case of a fall.
Gloves: use them all year round to protect the hands.
Goggles: if the helmet does not have a visor, use goggles to protect the eyes.
Motorcyclists are not required to wear a reflective vest.

Reflective vest and triangles

The reflective vest must be approved and put on before leaving the vehicle, whenever you step onto the roadway or hard shoulder on interurban roads. In the car it is only mandatory to carry one vest, not one per occupant. The hazard pre-signalling triangles (V-1) must be placed in the event of any breakdown or immobilisation, even if the hazard lights or position lights are used. Today the V-16 light signal is also authorised.

4. Safe driving and special situations

The higher the speed, the greater the probability and severity of injuries in case of accident. Preventive driving consists of anticipating risks and maintaining an adequate safety distance: the higher the speed, the greater the distance.

Parking on a slope

On a downhill slope: engine off, parking brake engaged and reverse gear engaged.
On an uphill slope: handbrake engaged and first gear engaged.

Blowouts and punctures

In the event of a blowout, brake gently and progressively, never abruptly. After a puncture, stop the vehicle as soon as possible off the road or in a safe place.

Tunnels and underpasses

If you anticipate being stopped for more than two minutes in a tunnel, turn off the engine.
If you are immobilised in an underpass, request help via the nearest emergency post.
In the event of a fire in a tunnel, abandon the vehicle leaving the key in the ignition and the doors open to facilitate the work of the emergency services.
If the vehicle stops at a level crossing, the first thing to do is evacuate all occupants.

Anyone towing a trailer must carry an approved fire extinguisher in working condition. On a motorcycle, remember that the front brake is operated with the right hand on the handlebar.

5. Traffic accidents: the PAS protocol

Accidents generate human and material costs that affect the whole of society, directly or indirectly. Conduct in the event of an accident is summarised in three steps: Protect, Alert and Help (PAS).

P – Protect

The first thing is to avoid new accidents and protect yourself. Immobilise the crashed vehicle by switching off the ignition and engaging the handbrake. Put on the reflective vest before getting out, place the V-16 signal or the pre-signalling triangles and move uninjured occupants away from the danger zone.

A – Alert

Call 112 providing accurate information: exact location of the accident, number of injured, apparent condition, type of vehicles involved and additional risks (fire, dangerous goods, etc.). If there are only minor injuries and safety has been restored, notifying the authorities is only mandatory if someone requests it.

S – Help

Provide basic help to the injured without putting yourself in danger and respecting some essential rules:

Never remove the helmet from an injured motorcyclist, except in case of immediate life-threatening risk.
Do not give the injured anything to drink or eat.
Do not move the injured, except in case of serious danger (fire, risk of being run over, etc.).
Reassure the victims and keep them warm until professional help arrives.

Duty of care and legal obligations

The duty of care obliges you to stop and assist the victims whenever there is no organised help already, even if you are not involved in the accident. Failing to help a helpless victim is a crime. If you are involved, you must stop, collaborate in restoring road safety and clarifying the facts without creating new danger. In the event of a serious accident, the three steps are always: stop the vehicle without risk, alert the authorities and assist the injured.