General Automotive FAQ

Driving with lights on at day

Is it worthwhile to buy a daytime running light?

The energy consumption of OSRAM LED daytime running lights is up to 90% lower compared to conventional low beam light during the day. This is achieved by very efficient LEDs and the fact that during daytime unnecessary lights are not turned on (license plate light, rear light, position light, dashboard light).

Furthermore the OSRAM LED daytime running lights have a very high lifetime (Tc>5000h; last a car lifetime) and don’t wear off the low beam light.

That is why the purchase of a daytime running light is not only good for your safety but on the long run also financially worthwhile.

How do other EU countries deal with the issue of daytime running lights?

The European Commission generally supports a uniform solution regarding daytime running lights and has decided that all new cars must be fitted with DRL's as of 2011. Until then there are different rules in the countries.

The following overview offers information on the current status (June 2009, source: ADAC - no responsibility is taken for the correctness and completeness of this information).

All-season compulsory daytime running lights in:

  • Bosnia-Herzegovina
  • Czech Republic
  • Denmark
  • Estonia
  • Finland
  • Hungary*
  • Iceland
  • Italy*
  • Latvia
  • Lithuania
  • Macedonia
  • Montenegro
  • Norway
  • Poland
  • Romania*
  • Russia*
  • Slovakia
  • Slovenia
  • Sweden

* on motorways and outside towns

Winter half year compulsory daytime running lights in:

  • Bulgaria (1. November until 31. March)
  • Croatia (last sunday in October until last sunday in March)

Limited duty of daytime running lights in:

  • Portugal - only on the IP5 from Vilar Formoso to Aveiro

Recommendation of daytime running lights in:

  • France
  • Germany
  • Switzerland

Prohibition of daytime running lights only in:

  • Greece (except vehicles with automatic DRL's)

In addition - in some countries like Croatia, Macedonia, Montenegro, Russia, Serbia, Slovakia and Spain - you have to carry replacement lamps with you. This is also recommended in Czech Republic, France, Hungary, Norway, Portugal and Slovenia. Also in that case, spare lamp kits with lamps for fundamental lighting functions are very convenient.

Isn't it enough to drive with the parking lights switched on instead of the dipped beam, if I want to be seen better during the day?

A very clear no!

Here we are dealing with an important security aspect for all motorists, whose aim it is to be seen as quickly as possible at day by all other road users. The function of the parking light is to make a parked car visible at night to other motorists. Daytime running light, however, is defined in a much more demanding and powerful way in order to guarantee visibility in every situation. The light emitted by parking lights is by far not strong enough to imitate this function; only dipped beam is suitable for this function.

By the way: driving with fog lamps switched on at day and without real impediment of visibility is forbidden in nearly every country of the EU!

Is there a higher safety-risk for motorcyclists because of more daytime running light?

Daytime running light has been limited to motorcyclists up to now to give them better protection through better visibility. This is why some voices have been raised who were worried that the introduction of daytime running light would lead to a deterioration of the present situation.

Such thinking assumes that the use of daytime running light by motorcars and trucks diminishes the perception of motorized two-wheeled vehicles and that an early visibility of these vehicles would therefore suffer. Extensive research, carried out in Lower Saxony e.g., has shown that a broad use of daytime running light offers additional safety to all road users. It is a proven fact that a vehicle with light is always caught more quickly by the human eye than a vehicle without light. This means that motorcyclists are now able to see other road users earlier, too, and this is an advantage which can help to avoid many motorcycle-accidents.

What is decisive is: everyone is seen better, no one is seen worse than before. And what is more: it is especially the weak road users (such as pedestrians and users of two-wheeled vehicles) who are able to see dangers (cars) more quickly.

Why should I use a daytime running light?

If you drive with daytime running light, you will increase your own safety and you will lower your risk of accidents considerably. 50% of all people involved in car accidents (even 80% of those who had an accident at a crossroad) state that they did not see the other vehicle at all or that they did not see it in time. Those who use daytime running light are definitely seen better. According to an EU-study, more than one million insurance accidents a year could be avoided across Europe by driving with daytime running lights. That would mean 155,000 fewer people injured and 5,500 fewer road deaths.

Bluish coated lamps

What are the advantages of OSRAM COOL BLUE INTENSE lamps?

Apart from the special visual appeal of a COOL BLUE INTENSE lamp in the headlight, a look that so many car drivers favour, the halogen headlamp also offers photometric improvements over standard lamps.

However not to the same extent as the lamps of the SILVERSTAR 2.0 range which provide up to 60% more light, or even better the NIGHT BREAKER UNLIMITED lamps with up to 110% more light on the road.

To achieve a uniform bluish light colour at the front of the vehicle, OSRAM also offers COOL BLUE INTENSE parking light lamps.

A COOL BLUE INTENSE version is available for:

Headlight lamps:

  • halogen lamps H1, H3, H4, H7, H8, H11, H15, HB3, HB4
  • gas discharge lamps XENARC COOL BLUE INTENSE D1S, D1R, D2S, D2R, D3S, D4S

Auxiliary lamps:

  • W5W

What is the advantage of OSRAM COOL BLUE INTENSE lamps in parking lights?

The W5W has a special coating so it produces a higher color temperature and therefore the impression of blue light.

COOL BLUE INTENSE sidelight lamps are a stylish addition to OSRAM XENARC and XENARC COOL BLUE INTENSE xenon lamps, as well as COOL BLUE INTENSE halogen headlight lamps to underline the bluish impression.

Which lamp types does OSRAM offer in a COOL BLUE INTENSE version?

COOL BLUE INTENSE or XENARC COOL BLUE INTENSE versions are available for:

Headlight lamps:

  • Halogen lamps: H1, H3, H4, H7, H8, H11, H15, HB3, HB4
  • Xenon lamps: D1S,D1R, D2S, D2R. D3S, D4S

Auxiliary lamps:

  • W5W

Headlight lamps with higher luminance


This all depends on personal requirements and preferences. Drivers who are looking for maximum performance and as much light as possible on the road ahead tend to choose OSRAM NIGHT BREAKER UNLIMITED with up to 110% more light than a standard lamp - or the SILVERSTAR 2.0 lamps range of headlight lamps offering up to 60% more light than a standard lamp.

Drivers who prefer good performance, high visibility and something a little different tend to choose lamps from the OSRAM COOL BLUE INTENSE range.

Of course, all these product ranges are fully ECE approved without restrictions for use on public roads throughout Europe.

Coated signal lamps

What does DIADEM mean regarding design and service life?

DIADEM and DIADEM CHROME lamps offer special appearances that amber lamps cannot offer. When switched off the lamps appear to be bluish or neutral (like chrome).

DIADEM lamps offer long life characteristics. The service life is up to double the time of regular amber bulbs.

Why does the OSRAM DIADEM flash yellow even though it looks opalescent white?

Special interference filters cause that transmitted light has a different colour (amber) than reflected light (bluish or neutral).

DIADEM DEEP AMBER lamps emit a very saturated amber colour. This deep amber colour provides a higher contrast during day time light.

Xenon headlight lamps

Which hazardous materials do these lamps contain?

The first generation of xenon headlight lamps (D1 and D2) are containing mercury (Hg). The second generation (D3; D4 and D8) is Hg free.

My dealer said a retrofit with Xenon HID is not possible for my car, although there are a lot of cars with xenon lamps on the road which didn't have HID from the start. Is it possible that I replace the existing headlights by a xenon version myself?

It is not possible to replace a halogen headlight with a Xenon HID-system by yourself.

Xenon lamps are only approved with for the use in dedicated xenon headlights. The exchange of a halogen lamp with a xenon lamp is strictly illegal and the use on public roads leads to cancellation of vehicle operating licence and loss of insurance cover.

What is the advantage of a XENARC lighting system compared to halogen headlights?

A XENARC lighting system provides more light and a much higher illumination of the road compared to a halogen system. It has a longer service life and a higher efficiency compared to halogen lighting.


How was it technically possible to combine 100% more light with a 100% extended service life, all in one lamp?

OSRAM single-coil technology is the secret of the TRUCKSTAR range. Up to now, physical limitations have meant that 24 Volt lamps were always equipped with a double coil. Double-coil lamps have major disadvantages when it comes to homogenous light density and even heat distribution throughout the coil. This leads to significant reductions in light distribution and service life.

After intensive research and development, OSRAM is proud to become the first manufacturer in the world to offer single-coil technology for 24V lamps. This represents a quantum leap in light technology and operating life. The result is a significant increase in light output and lifetime of TRUCKSTAR PRO for the trucking industry and its drivers.

Can the OSRAM TRUCKSTAR PRO lamps be used universally, and are they ECE approved?

Yes, of course all products of the TRUCKSTAR PRO range fully meet ECE R37 requirements, and have been approved for all uses. So you can replace your 24V standard lamps now with the appropriate TRUCKSTAR PRO bulb of the same category, and immediately enjoy the improved light and extended service life.

Are there TRUCKSTAR PRO signal lamps available as well?

OSRAM has extended its TRUCKSTAR PRO portfolio with several light sources for signal lighting.

These bulbs offer extended service life and higher vibration resistance in comparison to regular 24V signal light sources.

High-wattage headlight lamps

Does the OSRAM range include "high-wattage" headlight lamps such as the H4 100/90 W?

Although OSRAM supplies all its standard halogen headlight lamps in high-wattage versions for selected markets, they are not approved for use on public roads. They may be used only in special applications like forestry, agriculture and mining vehicles as well as off-road vehicles such as rally cars. Using them on public roads may cause the authorities to withdraw the license for the vehicle and therefore its insurance coverage.

Drivers who want a little more light in their headlights should look for the OSRAM SILVERSTAR 2.0 or even better NIGHTBREAKER UNLIMITED headlamps. These lamps still comply with legal requirements, but offer up to 110% higher luminance on the road and an up to 40m longer beam (compared to standard lamps).

Long lasting lamps

The combination of the massive filament, rare filling gas composition and high gas pressure give all the preconditions for a long lasting product.

OSRAM is committed to the high quality of the ULTRA LIFE & XENARC ULTRA LIFE lamps and offers a 3+1 year guarantee ULTRA LIFE halogen headlight lamps and a 10 year guarantee for XENARC ULTRA LIFE xenon lamps. Both guarantees are for end-consumers only combined with an online registration.

Here's how the guarantee works.

Motorcycle lamps

Is it possible to use use a lamp, e.g. H7 55W PX26d, which is dedicated for the car in a motorcycle?

Yes, this is possible, as in general every car lamp can be either used in a car or a motorcycle if the headlight is approved for these lamp types. E.g. if the headlamp is approved to be used with H7 ECE category, every lamp which fulfills the ECE R37 norm category H7 requirements and is E-marked can be used for this application. There are some ECE categories, which are explicitly dedicated for the motorcycle use only, such as S1 or S2. As the motorcycle headlamp systems are exposed to higher vibrations than the car headlamp systems we recommend to equip motorcycle headlamps with the products dedicated for the motorcycles as they were tested for vibration resistance.

What is the exact difference between car and motorcycle lamp?

The difference is, that the motorcycle lamps are being additionally tested according NBR Heavy Duty vibration test (IEC 60810 Standard). With this additional test we make sure, that the lamps are able to withstand higher vibrations requirements of the motorcycle vehicles.

What's so special about motorcycle lamps?

The lamps are being tested according NBR heavy duty vibration test (IEC 60810 Standard). This standard simulates the background noise caused by engine and the vibrations caused by the road surface. The profile of this test was developed by universities and reflecting real conditions on the road.


What do the informations on the bulb mean?

OSRAM automotive lamps have the following information on them:

  • OSRAM or OS indicates the manufacturer, in this case OSRAM.
  • 12 or 12V, 24 or 24V indicates the rated voltage according to ECE Regulation 37.
  • H1, H4, P21W etc. are the standard international categories for ECE standardized bulbs, e.g. 55W stands for a rated wattage of 55W.
  • E1 indicates the country in which the bulb has been tested and approved ("1" for Germany).
  • If DOT appears on a bulb it means that it's approved for the US market (necessary only for main headlight bulbs - low and high beam).
  • The uppercase "U" indicates a UV-reduced bulb in accordance with ECE requirements (e.g. for use in plastic headlights). All OSRAM halogen automotive bulbs meet these requirements.
  • The approval mark issued by the relevant authority (the Federal Road Traffic Office in Flensburg in the case of E1) is also displayed and is either 37R (E1) a 5-digit number or just (E1) a 3-digit number (which may comprise alphanumeric characters).Almost all bulbs carry the manufacturer's own code so that the manufacturer can trace the production batches

Because of the size of some light sources it may not always be possible to show all the information. By law, approved bulbs must show the manufacturer, rated voltage, wattage, test marks (e.g. E1) and approval marks.

Do auxiliary lamps for the automotive sector have to be standardized?

In general, replaceable bulbs on the outside of the vehicle must be approved. In addition to the headlights, these include the signal lights such as indicators, brake lights, taillights, fog lights, parking lights, reversing lights and registration plate lights. They are standardized in ECE Regulations 37 and 99 (Economic Commission for Europe). One of the benefits of standardization is that the bulbs can be replaced by the same bulbs from other manufacturers.

Another benefit is that they cannot be confused with other lamps, which means that traffic safety is not impaired.

Light sources inside the vehicle do not need to be standardized but in most cases they comply with standard lamp and base specifications.

What do B3 and Tc mean in connection with the service life of bulbs?

If we consider the service lives of products that are designed to last a certain time, we can see that they all have the same or similar failure characteristics.

If we plot the service lives of the individual bulbs on special logarithmic graph paper, the graph produced is called a "Weibull distribution curve".

In a stable production process we obtain a straight line for the service life on which we can read off various life values. For its products in the automotive sector OSRAM specifies a B3 value, which indicates the time at which 3% of the tested bulbs have failed. OSRAM also specifies the Tc value (characteristic Weibull value), which indicates the time at which 63.2% of the bulbs have failed.

In former times only the average value was specified (the average life), which in this system would correspond to a B50 value (i.e. the time at which 50% of the bulbs have failed). By specifying both the B3 value and the Tc value it is possible to get an idea of the spread of the product's service life and hence the quality of the product.

In America B10 is also given. This value can be calculated from the B3 and Tc values.

My headlights have condensation inside. Is that normal, and what can I do to remedy it?

Driving in the rain or using a high-pressure water jet cleaner in a car-wash can cause moisture to enter the headlights and this small amount of condensation in the headlights is not a quality fault.

Since this can occur during the transition period, this condensation in the headlights is considered to be normal. This should normally disappear again after a short period as a result of air circulation.

A common cause of vehicle lights showing condensation is often incorrect operation of a high-pressure water jet cleaner when washing the vehicle. We therefore recommend never directing the water jet at the headlights and you should maintain a distance of 30 cm from the vehicle.

If you need further help, do not hesitate to contact our OSRAM Technical Customer Service (, hotline: +49 89 62 13 33 22).

Which fault mechanisms affect the life of miniature incandescent (halogen) bulbs in automotive applications (lamps with small filament diameters)?

  • Vibration and shock
  • The ambient temperature in the headlight or luminaire
  • The power supply
  • Corrosion in socket leading to poor contact between the socket connectors and the bulb
  • Other factors, including inadequate quality or poor handling during the production process by the lamp manufacturer, the setmaker or the car manufacturer.

Is there an incandescent (halogen) bulb that will last forever?


The laws of physics dictate that there is no such thing as an incandescent (halogen) bulb that can last forever. When current flows through a filament some of the filament inevitably vaporizes. After a while this results in the filament burning out.

It is possible to design an incandescent bulb so that it lasts a long time. However, there is always a compromise involved because the luminous efficacy is reduced (i.e. the amount of light that can be generated from a particular input power). The filament can be operated at a lower temperature, or a thicker filament can be used, so that it takes longer for the filament to vaporize and burn out.

An important consideration is safety. Bulbs with an extremely long life would not meet current requirements for headlights. Because they would not generate sufficient light output to make a satisfactory beam pattern.

How can I legally get more light on the road?

The simplest and most cost-effective way is to replace standard halogen headlight bulbs by the corresponding SILVERSTAR 2.0 or even better the NIGHT BREAKER UNLIMITED version. OSRAM NIGHT BREAKER UNLIMITED headlamps provide up to 110 % more light on the road and an up to 35m longer beam (compared to standard halogen lamps).

Another way is to replace the complete headlight with a new headlight system designed for OSRAM XENARC xenon lamps. This option offers maximum light for every driver. Ask your dealer whether your car can be fitted with these headlights.

What is MSCP?

Different information is provided for American automotive bulbs than for European lamps. In the American market, for example, they specify the current that the lamp draws, in amps, rather than the lamp wattage. Likewise, the luminous flux of the lamp is not given in lumen but in MSCP, which stands for "mean spherical candle power".

For converting from MSCP to luminous flux, the rule of thumb is average luminous intensity in MSCP * 4 * π = luminous flux in lumen.

What is the difference between nominal voltage and the statutory test voltage?

The nominal voltage, also known as the rated voltage, is the value that has to be stamped on the lamp in accordance with the provisions of ECE R37; in this case 12V or 24V.

The test voltage, which is also defined in ECE R37, is the voltage for which the lamp is designed and at which all the values prescribed by the relevant standards have to be met.

For example, the test voltage is 13.2V for headlight lamps, 13.5V for auxiliary lamps and 28.0V for lamps in 24 Volt systems.

Do OSRAM automotive lamps have to be recycled?

Conventional automotive lamps such as those for indicators, brake lights, tail lights and interior lights, do not contain any substances that will harm the environment, so no special waste disposal measures need to be taken. The same applies to halogen headlight lamps.

Xenon lamps and miniature fluorescent lamps (e.g. in busses, dashboard lighting) contain mercury (about one thousandth of a gram per lamp), so they have to be taken for recycling.

In the case of "electronic light" the electronic components such as control gears have to be disposed off as electronic waste.

In Germany, OSRAM takes part in the Dual System. The packaging for OSRAM products is therefore labelled with the "Grüner Punkt" (Green Dot) symbol. These products are disposed of in Dual System containers.

Why do headlight bulbs have to have reduced UV emission?

More and more headlights are now being manufactured with plastic components to save on weight and cost. Especially, almost all the clear headlight covers on new cars these days are made of plastic. The effect of UV radiation from light sources or from the sun on transparent plastics is well documented; over a lengthy period of time the plastic turns yellow and brittle, and this process is speeded up by high material temperatures.

OSRAM UV filter lamps comply with the statutory regulations of ECE Standard R37 (except off-road lamps) with regard to UV thresholds and can therefore be used without restriction in plastic headlights.

This property is indicated on the packaging by the "UV FILTER" symbol. On the lamp itself you will see the letter "U". All OSRAM halogen headlight lamps are UV filter lamps.