A brake light is a red light system on the rear of a vehicle that illuminates when the driver applies the brakes . Brake lights warn drivers behind you that the vehicle is slowing down or stopping, which is essential for road safety .
1. Features of a brake light
✅ Automatically activated when braking → Works via the brake pedal switch .
✅ Bright red light → Red is the standard color according to international regulations.
✅ At least two brake lights are mandatory → Placed on the left and right side of the rear of the vehicle.
✅ Additional third brake light (CHMSL) on modern cars → Center, positioned higher for extra visibility.
✅ Can be halogen, LED or neon → Modern brake lights usually use LED technology for faster response and longer life.
2. Types of brake lights
| Brake light type | Location | Features |
|---|---|---|
| Standard brake lights | Left and right at the back | Bright red, lights up when braking |
| CHMSL (Center High Mount Stop Lamp) | Middle, higher positioned (above rear window or on trunk) | Improves visibility in heavy traffic |
| Adaptive brake lights | Standard brake light with additional functions | May flash or brighten in an emergency stop |
| Dynamic brake lights | LED brake lights with a variable pattern function | Flashing or pulsating in some vehicles during sudden braking |
📌 CHMSLs have been mandatory in many countries since the 1980s to reduce rear-end collisions.
3. Operation of brake lights
🔹 Step 1: Driver presses the brake → Pressure sensor in the brake pedal activates the brake lights .
🔹 Step 2: Brake lights will stay on continuously as long as the brake is pressed.
🔹 Step 3: With adaptive or dynamic systems, the brake lights may flash during emergency braking.
🔹 Step 4: When the driver releases the brake, the brake lights go off.
📌 Modern cars have smart brake light systems that adjust intensity based on braking force.
4. Difference between brake lights and other tail lights
| Light type | Goal | Colour | When active? |
|---|---|---|---|
| Brake lights | Warn drivers behind you when braking | Red (bright) | Only when braking |
| Rear lights (driving lights) | Ensures that the vehicle is visible in the dark | Red (dim) | Always on with lights |
| Rear fog light | Increases visibility in fog | Bright red | Only in dense fog |
| Turn signals (indicators) | Gives direction | Orange | When turning or changing lanes |
📌 Brake lights are brighter than standard taillights and only come on when braking.
5. Legislation and obligation
📌 Two brake lights required on all motor vehicles.
📌 Third brake light (CHMSL) mandatory on cars in the US since 1986 and in the EU since 1998.
📌 Flashing brake lights permitted in some countries in case of emergency braking (e.g. Germany and Japan).
📌 Brake lights must be functional → Defective brake lights can result in a fine or rejection during the MOT inspection .
💡 In short:
A brake light is a bright red taillight that automatically turns on when braking to warn drivers behind you. Cars have at least two brake lights , and modern vehicles have a third brake light (CHMSL) for improved visibility.