13.1 Introduction

Traction, tyres, and brakes form the foundation of vehicle safety. Traction refers to the grip between the tyres and the road, while tyres ensure that this grip is maintained under various conditions. Brakes allow the driver to slow down or stop safely. Proper maintenance and understanding of these elements are essential for accident prevention.

13.2 Vehicle Traction

13.2.1 What is Traction?

Traction is the force that allows the vehicle's tyres to grip the road surface. It is necessary for accelerating, braking, and steering. The level of traction varies with road condition, tyre type, weather, and vehicle load.

13.2.2 Factors Affecting Traction

• Road surface: wet, icy, or gravel roads reduce traction.
• Tyre condition and pressure: worn-out or underinflated tyres decrease grip.
• Vehicle speed: higher speeds reduce tyre-road contact time.
• Load: an overloaded vehicle alters weight distribution and traction.

13.2.3 Loss of Traction: Aquaplaning

13.2.4 Traction on Snow and Ice

• Use snow chains or winter tyres.
• Accelerate and brake gently. Use high gears to avoid wheelspin.
• Descend hills in low gears, using engine braking.
• Avoid sudden manoeuvres or abrupt braking.

13.3 Tyres

Vehicle wheels are made up of two parts:

Tyre failures are a common cause of traffic accidents, so it is very important they meet proper quality standards. On new or good-condition tyres, specifications can be read on the sidewall. They must not have bulges, deformities, or cuts; no layers should be coming loose; and there should be no exposed cables or cracks.

The part of the tyre in contact with the road is the tread. For passenger cars, the tread must have grooves at least 1.6 mm deep. These grooves allow the tyre to:

• Avoid overheating.
• Be more flexible and roll more smoothly.
• Grip the road surface better.
• Expel water collected from the road when it rains.

13.3.1 Tyre Pressure

The manufacturer determines the correct amount of air each tyre should have - the inflation pressure. Check pressure when tyres are cold, at least once a month. Always carry a spare wheel at the correct (maximum recommended) pressure if possible. Incorrect pressure causes uneven wear, poor grip, and higher fuel consumption.

13.3.2 Tread Depth

• Legal minimum: 1.6 mm.
• Recommended: replace when below 3 mm for safety, especially in wet conditions.

13.3.3 Tyre Maintenance

• Check for cracks, cuts, bulges, or foreign objects.
• Replace all four tyres, or at least both on the same axle, with the same type, size, and category.
• Avoid mixing tyres of different types (radial/bias) or seasons (summer/winter).

Tyre wear. Rubber wears down due to friction with the road, so replace tyres every five years even if they appear to be in good condition.

Causes of premature wear:

• Harsh or aggressive driving.
• Very high speeds.
• Weather conditions - tyres wear more in summer.
• Heavy loads carried by the vehicle.
• Incorrect inflation pressure.
• Poor road conditions.
• Brake issues or other vehicle faults affecting the wheels.

13.3.4 Tyre Blowout

In case of a sudden blowout:

• Hold the steering wheel firmly.
• Do not brake suddenly; decelerate gradually.
• Pull off the road and stop safely.

13.3.5 Wheel Balancing

Wheel balancing consists of adding weights to the rims so the wheels properly support the vehicle's weight and load. This balance is essential for the wheels to rotate smoothly. Wheels can become unbalanced due to:

• Tyre replacement.
• Loss of wheel weights.
• Dented or damaged rims.
• Tyre wear or cuts.

How to tell a wheel is out of balance: noise and vibration from the vehicle, excessive or abnormal tyre wear, and loose wheel nuts.

13.4 Brakes

The brakes reduce the vehicle's speed until it comes to a complete stop. Braking systems rarely fail, but when they do it may cause a serious accident.

13.4.1 Types of Brakes

13.4.2 How to Brake Properly

• Brake progressively and early to reduce wear and avoid abrupt stops.
• Use engine braking (downshifting) on long descents.
• In case of emergency braking with ABS: press the pedal firmly and do not release it.

13.4.3 Brake Safety Systems

Engine Braking

Reduces speed without using the wheel brakes - it works when you release the accelerator, so the engine holds the vehicle back. In lower gears (1st or 2nd) the braking effect is greater. Recommended on long downhill stretches.

ABS - Anti-lock Braking System

Prevents the wheels from locking during emergency braking, preserving steering control. Press the pedal firmly and hold it. A vibration or noise may be felt - this is normal with ABS activation.

Autonomous Emergency Braking (AEB)

Uses a radar sensor to calculate the distance kept to the vehicle ahead. If the gap is too small, it warns the driver with audible/voice alerts; if the driver does not react and a collision is likely, it applies emergency braking to avoid or mitigate impact.

Emergency Brake Warning (ESS/EBD)

Alerts the following driver that the vehicle ahead must perform an emergency stop. On hard, quick braking the brake lights flash, giving the driver behind more time to brake. In some vehicles the hazard lights may also activate after hard braking.

13.4.4 Brake Fade

This happens when brakes overheat due to prolonged use (especially on slopes), reducing their effectiveness. Prevent it by using engine braking and avoiding prolonged foot-brake use.

13.4.5 Brake Failure Response

• Pump the pedal to activate residual pressure.
• Use engine braking and reduce gear.
• Apply the handbrake progressively if needed.
• Steer towards an uphill road, soft barrier, or stop area.

13.4.6 Common Brake Problems

13.5 Suspension and Braking

The suspension maintains tyre-road contact. A faulty suspension increases braking distance and reduces control. Signs of wear: bouncing on bumps, uneven tyre wear, and drifting in curves. Have the suspension inspected during regular maintenance.

13.6 Summary

• Ensure tyres are in good condition, with correct pressure and tread depth.
• Understand how traction varies depending on the surface and conditions.
• Use snow chains, winter tyres, or traction devices in adverse conditions.
• Check brakes regularly and know how to respond in emergencies.
• Use engine braking on long descents.