Every driver has encountered a situation where it is necessary to leave a car in a parking lot at night or to mark their vehicle in poor visibility conditions. It is for these purposes that the design of any car includes special lighting devices, which are commonly called “dimensions”. Many beginners confuse them with low beam headlights or modern running lights, not understanding the fundamental difference in functionality and legal responsibility for their use.
In this article we will analyze the design of side lights in simple terms, explain why they burn dimmer than the main optics and what requirements the traffic rules impose on them. Understanding of operating principles side lighting will help you not only avoid fines from traffic police inspectors, but also protect your car from accidental collisions in the parking lot.
It is important to note that despite its apparent simplicity, the side lighting system has its own technical nuances related to the type of lamps used and the electrical connection diagram. Ignoring the malfunction of even one light element may cause an emergency situation, especially if the car is parked on an unlit section of the road.
Main purpose and operating principle
The main task of side lights is to indicate the actual size of the vehicle to other road users. Unlike headlights, which actively illuminate the road surface, these devices only mark the boundaries of the body. Side light allows the driver driving behind or towards you to assess the width and height of your car, which is especially critical on narrow roads or when maneuvering in heavy traffic.
The principle of operation of the system is extremely simple: when the corresponding switch is turned on, electric current is supplied to the lamps installed in the front and rear of the car. The power consumption of such lamps is significantly lower than that of headlights, which allows them to be left on for a long time without the risk of rapid discharge battery.
According to technical regulations, the front lights must emit white light, and the rear lights must emit red light. This color coding is international and allows you to instantly determine the direction of movement of the vehicle even in complete darkness. Violating the color scheme, for example, installing blue or yellow lamps in the dimensions, is a direct violation of the rules and can lead to a ban on operation.
If you notice that one of the lights is dimmer than the other, check the socket contacts - oxidation often reduces the brightness of the glow and distorts the perception of the car’s dimensions by other drivers.
Differences between dimensions and running lights (DRLs)
With the introduction of Daytime Running Lights (DRLs) into vehicle fleets in many countries, confusion has arisen among drivers. Many people believe that bright LED strips during the day replace the need to turn on the headlights, but this is not entirely true. Running lights are intended solely to improve the visibility of the vehicle during daylight hours and have nothing to do with indicating the dimensions in the dark.
The key difference lies in the brightness and operating mode. The DRLs light up very brightly to be visible even in the sun, while the headlights should shine moderately so as not to dazzle others at night. If you turn on the side lights during the day, they may simply not be visible, and if you use DRLs at night instead of headlights or side lights, this will not indicate the rear part of the car for those driving behind.
- 🚗 Side lights are turned on by the driver manually or automatically with the main light, and DRLs are often activated themselves when the engine is started.
- 💡 The brightness of the DRLs is several times higher than the intensity of the glow of the dimensions, which makes them unsuitable for use as night parking lights.
- ⚖️ The legislation clearly distinguishes between these concepts: the absence of working DRLs during the day may result in a fine, as well as faulty dimensions at night.
Modern cars are often equipped with automatic equipment that, when the low beam headlights are turned on, reduces the brightness of the DRLs or switches them to headlight mode. However, in older models or budget versions these functions are separated, and the driver must independently control the position of the lever light switch.
Types of lamps and modern technologies
For decades, incandescent lamps have been the standard for parking lights. They are cheap, easy to replace and give an even light. However, with the development of the automotive industry, they were replaced by more effective solutions. Today in headlights you can find halogen, xenon (rare for dimensions) and, most often, LED modules (LED).
LEDs have a number of undeniable advantages: they consume a minimal amount of energy, last many times longer than conventional lamps and light up instantly. This is especially important for brake lights, but the system's quick response is also useful for dimensions. In addition, LED technologies allow designers to create unique light patterns that become the “calling card” of the brand, such as the famous “angel eyes” or complex geometric patterns.
However, LEDs also have their own characteristics. They are sensitive to voltage drops in the on-board network, so they often require the installation of additional stabilizers or drivers. When replacing a conventional lamp with an LED one in older cars, it may be necessary to install decoys (resistors) so that the on-board computer does not generate an error about a burnt-out light source.
⚠️ Attention: When installing LED bulbs in dimensions, make sure they are at the correct color temperature. A too cold, bluish tint may be regarded by the inspector as a violation of the requirements for the color of external lighting devices.
Rules of use according to traffic rules
The rules of the road clearly regulate when and how side lights must be used. The main area of their application is in the dark and in conditions of insufficient visibility. If you are stopped on the side of the road at night, turning on side light is a mandatory safety requirement.
In populated areas where there is artificial lighting, driving with only the headlights on is prohibited - you must use low beam headlights. Dimensions in motion are used only in combination with other lighting devices or in special situations specified by law, for example, when towing or as part of a road train to indicate extreme points.
It is important to remember situations when visibility is limited not by the time of day, but by weather conditions. Fog, rain or snow require increased attention. Although fog lights take priority in fog, the headlights must always be on when the vehicle's external lights are on so that the outline of the vehicle is visible.
☑️ Checking readiness for the night
Comparison table of characteristics of lighting devices
To finally systematize the knowledge about car lighting equipment, consider a comparative table. It will help you understand the difference in power, purpose and legal status of various light sources.
| Parameter | Side lights | Low beam headlights | Daytime running lights (DRL) |
|---|---|---|---|
| Main function | Size designation | Lighting the road ahead | Improved visibility during the day |
| Glow color | White (front), red (back) | White or yellow | White |
| Power (approx.) | 5 W (incandescent) | 55-60 W | 10-20 W (LED) |
| Operating mode | Permanent (parking, night) | On the move at night | Only when the engine is running |
The table shows that the dimensions are the least energy-intensive devices, which makes them ideal for long-term parking. However, their luminous flux is insufficient to illuminate the path, so it is absolutely impossible to rely on them when moving in complete darkness.
Typical faults and diagnostics
Despite the simplicity of the design, the side lighting system is susceptible to various malfunctions. The most common problem is the burnout of the filament in the lamp. In modern cars, this will be instantly reported by an indicator on the dashboard, but in older models, the driver can only learn about the problem from other road users or an inspector.
A common problem is oxidation of contacts in the cartridge. Moisture entering the headlight through leaky seals leads to the formation of an oxide film on the lamp base. This increases resistance and causes heat, which can eventually cause the plastic of the cartridge to melt. Regular visual inspection of condition contact group helps avoid costly repairs.
Another cause of failure could be a faulty switch or fuse itself. If all the dimensions stop lighting at once, there is no point in looking for a problem in the lamps - you need to check the integrity of the fuse in the mounting block. Usually it is marked with the corresponding symbol or inscription in the diagram on the block cover.
Why are the lights flashing?
If the lights start flickering or blinking, this often indicates a bad ground (ground). Check the fastening of the negative wire to the car body - rust under the bolt may interrupt the circuit.
Legal aspects and penalties
The use of lighting devices is regulated not only by traffic regulations, but also by the “List of faults” under which the operation of the vehicle is prohibited. Faulty dimensions in the dark or in foggy conditions refer to malfunctions in which movement is prohibited until the cause is eliminated. The inspector has every right to issue a fine and prohibit further movement.
The issue of tuning deserves special attention. Many car enthusiasts strive to make their car more noticeable by installing high-power lamps or changing the color to a non-standard one. Installation of lamps that do not correspond to the type of lighting device may result in deprivation of rights, since this is equivalent to the installation of special signals or a change in design that affects safety.
The most critical violation is the installation of red lamps in the front lights and white lamps in the rear ones, as this disorients other drivers regarding the direction of travel of your car.
Exterior lighting fixtures are required by law to conform to the design certified for the vehicle model. Any deviations may be considered a violation.
Is it possible to drive with one working light?
Driving with one parking light inoperative at night or in conditions of poor visibility is prohibited. This creates an emergency situation, as other drivers may incorrectly assess the dimensions of the vehicle. The inspector has the right to issue a fine under the relevant article of the Code of Administrative Offenses.
Do I need to include clearances in the tunnel?
Yes, the tunnel belongs to sections of the road with insufficient visibility, even if there is artificial lighting. The rules oblige drivers to turn on low beam headlights, which automatically or forcefully include side lights, to indicate the vehicle.
Why are the dimensions called "license plate lights"?
Body dimensions and license plate lights are often confused in everyday life. These are technically different lamps, but they are often powered from the same circuit or turned on at the same time. License plate lights are required to read the registration plate in the dark, and their failure will also result in a fine.
Does frost affect the operation of side lamps?
Regular incandescent bulbs are less sensitive to cold than LEDs. Cheap LED modules may lose brightness or operate unstably at extremely low temperatures if they are not designed for use in harsh climates. High-quality automotive optics are tested at temperatures down to -40°C.