A modern vehicle uses different kinds of lamps for multiple purposes: illumination for the driver to be able to drive in dark conditions, illumination to be seen and lights for information displays. Types of these lamps vary depending on the purpose and different car manufacturers and models use different types, with lamp bases adapted for vibration. The types of lamp approved and the bulb designations used vary in different parts of the world.

Filament lamps

Beginning in 1958, the United Nations Economic Commission for Europe

United Nations Economic Commission for Europe

The United Nations Economic Commission for Europe was established in 1947 to encourage economic cooperation among its member states. It is one of five regional commissions under the administrative direction of United Nations headquarters. It has 56 member states, and reports to the UN Economic and...

 (UNECE) standardized the following three groups of filament bulb categories to be used in vehicles and trailers sold in Europe. Some ECE-approved bulb types are also permitted by other regulations, such as those of the United States or of Japan—though Japan has adopted ECE regulations.

Group 1 (Without general restrictions)

Category	Filaments	Nominal power (High/Low beam where applicable)	Comments & Approvals	Image
R2	2	6V & 12V: 45/40W 24V: 55/50W	ECE P45t-41 base
H1	1	6V & 12V: 55W 24V: 70W	ECE, USA, Japan P14.5s base
H3	1	6V & 12V: 55W 24V: 70W	ECE, USA, Japan PK22s base
H4	2	6V & 12V: 60/55W 24V: 75/70W	ECE, Japan P43t-38 base US designation 9003/HB2
H7	1	12V: 55W 24V: 70W	ECE, USA, Japan PX26d base
H8	1	12V: 35W	ECE, USA PGJ19-1 90° base
H8B	1	12V: 35W	ECE, USA PGJY19-1 socketless base
H9	1	12V: 65W	ECE, USA PGJ19-5 90° base
H9B	1	12V: 65W	ECE, USA PGJY19-5 socketless base
H10	1	12V: 42W	ECE, USA PY20d 90° base
H11	1	12V: 55W 24V: 70W	ECE, USA PGJ19-2 90° base
H11B	1	12V: 55W 24V: 70W	ECE, USA PGJY19-2 socketless base
H12	1	12V: 53W	ECE, USA PZ20d 90° base
H13	2	12V: 60/55W	ECE, USA P26.4t 180° base
H13A	2	12V: 60/55W	ECE, USA PJ26.4t 90° base
H14	2	12V: 60/55W	ECE, Japan P38t base
H15	2	12V: 55/15W 15W filament for DRL function	ECE, USA PGJ23t-1 socketless base
H21W	1	12V & 24V: 21W	ECE BAY9s base
H27W/1	1	12V: 27W	ECE US designation: 880 PG13 180° base
H27W/2	1	12V: 27W	ECE US designation: 881 PGJ13 90° base
HB3	1	12V: 60W	ECE, USA P20d 90° base
HB3A	1	12V: 60W	ECE, USA P20d 180° base
HB4	1	12V: 51W	ECE, USA P22d 90° base
HB4A	1	12V: 51W	ECE, USA P22d 180° base
HIR1	1	12V: 60W	ECE, USA PX20d 90° base
HIR2	1	12V: 55W	ECE, USA PX22d 90° base
HS1	2	6V & 12V: 35/35W	ECE PX43t base
HS2	1	6V & 12V: 15W	ECE PX13.5s
HS5	2	12V: 35/35W	ECE P23t base for motorcycles
HS6	2	12V: 40/35W	ECE PX26.4t base
PX24W	1	12V: 24W	ECE PGU20-7 base
PSX24W	1	12V: 24W	ECE PG20-7 base
S2	2	6V & 12V: 35/35W	ECE BA20d base for motorcycles
S3	2	6V & 12V: 15W	ECE P26s base for mopeds

Group 2 (Only for use in signalling lamps, cornering lamps, reversing lamps and rear registration plate lamps)

Category	Cap (Base)	Filaments	Nominal Power (Major/Minor where applicable)	Comments	Image
C5W	SV8.5	1	6V, 12V, 24V: 5W	Old designation: C11
H6W	BAX9s	1	12V: 6W
HY6W	BAZ9s	1	12V: 6W	Amber
HY21W	BAW9s	1	12V & 24V: 21W	Amber
P13W	PG18.5d-1	1	12V: 13W
P19W	PGU20-1	1	12V: 19W
PR19W	PGU20-5	1	12V: 19W	Red
PY19W	PGU20-2	1	12V: 19W	Amber
PS19W	PG20-1	1	12V: 19W
PSR19W	PG20-5	1	12V: 19W	Red
PSY19W	PG20-2	1	12V: 19W	Amber
P21W	BA15s	1	6V, 12V, 24V: 21W	Old designation: P25-1
PR21W	BAW15s	1	12V & 24V: 21W	Red
PY21W	BAU15s	1	12V & 24V: 21W	Amber
P21/4W	BAZ15d	2	12V & 24V: 21/4W
PR21/4W	BAU15d	2	12V & 24V: 21/4W	Red
P21/5W	BAY15d	2	6V, 12V, 24V: 21/5W	Old designation: P25-2
PR21/5W	BAW15d	2	12V & 24V: 21/5W	Red
P24W	PGU20-3	1	12V: 24W
PR24W	PGU20-6	1	12V: 24W	Red
PY24W	PGU20-4	1	12V: 24W	Amber
PS24W	PG20-3	1	12V: 24W
PSR24W	PG20-6	1	12V: 24W	Red
PSY24W	PG20-4	1	12V: 24W	Amber
P27W	W2.5x16d	1	12V: 27W
P27/7W	W2.5x16q	2	12V: 27/7W	US designation: "3157"
PR27/7W	WU2.5x16	2	12V: 27/7W	Red
PY27/7W	WX2.5x16q	2	12V: 27/7W	Amber US variant: "3757A"
R5W	BA15s	1	6V, 12V, 24V: 5W	Old designation: R19/5
RR5W	BAW15s	1	12V & 24V: 5W	Red
R10W	BA15s	1	6V, 12V, 24V: 10W	Old designation: R19/10
RR10W	BAW15s	1	12V & 24V: 10W	Red
RY10W	BAU15s	1	6V, 12V, 24V: 10W	Amber
T1.4W	P11.5d	1	12V: 1.4W
T4W	BA9s	1	6V, 12V, 24V: 4W	Old designation: T8/4
W2.3W	W2x4.6d	1	12V: 2.3W
WY2.3W	W2x4.6d	1	12V: 2.3W	Amber
W3W	W2.1x9.5d	1	6V, 12V, 24V: 3W	Old designation: W10/3
W5W	W2.1x9.5d	1	6V, 12V, 24V: 5W	Old designation: W10/5
WR5W	W2.1x9.5d	1	12V & 24V: 5W	Red
WY5W	W2.1x9.5d	1	6V, 12V, 24V: 5W	Amber
W15/5W	WZ3x16q	2	12V: 15/5W	for motorcycles
W16W	W2.1x9.5d	1	12V: 16W	US designation: "921"
W21W	W3x16d	1	12V: 21W	US designation: 7440
WY21W	WX3x16d	1	12V: 21W	Amber US designation: 7440NA
WP21W	WY2.5x16d	1	12V: 21W
WPY21W	WZ2.5x16d	1	12V: 21W	Amber
W21/5W	W3x16q	2	12V: 21/5W US designation: 7443
WR21/5W	WY3x16q	2	12V: 21/5W	Red

Group 3 (For replacement purposes only)

Category	Cap (Base)	Filaments	Nominal power	Comments	Image
C21W	SV8.5	1	12V: 21W	Old designation: C15, for reversing lamp only
S1	BA20d	2	6V & 12V: 25/25W	for motorcycles

High-intensity discharge lamps

UNECE has also standardized high-intensity discharge (HID) ("xenon") lamps.

Category	Cap (Base)	Nominal power	Comments & approvals	Image
D1R	PK32d-3	85V/35W	ECE, USA Integral ignitor, for reflector systems
D1S	PK32d-2	85V/35W	ECE, USA Integral ignitor, for projector systems
D2R	P32d-3	85V/35W	ECE, USA For reflector systems
D2S	P32d-2	85V/35W	ECE, USA For projector systems
D3R	PK32d-6	42V/35W	ECE, USA Mercury-free, integral ignitor, for reflector systems
D3S	PK32d-5	42V/35W	ECE, USA Mercury-free, integral ignitor, for projector systems
D4R	P32d-6	42V/35W	ECE, USA Mercury-free, for reflector systems
D4S	P32d-5	42V/35W	ECE, USA Mercury-free, for projector systems

The wattage rate of all standardized HID ballasts is 12V/35W.

Old types

This section lists lamp types withdrawn from ECE Regulation 37, so are no longer permitted in lamps or vehicles submitted for new type approvals, but which may still be produced for service replacement on older lamps.

Category	Filaments	Nominal power	Comments	Image
H2	1	12V/55W

Germany

Beside the ECE Regulations there are some national regulations in Germany for vehicle bulbs. This regulations are predecessor of the ECE Regulations, but are still in effect. Interchangeable light sources of facilities which have to meet design specifications are required to be conform to an official approved design. That is written in § 22a, Subsection 1, No. 18 of the "Straßenverkehrs-Zulassungs-Ordnung (StVZO)" road traffic admission regulation. As per the "Fahrzeugteileverordnung (FzTV)" vehicle parts regulation from August 12th, 1998, published in the "Bundesgesetzblatt (BGBl.)" federal law publication (BGBl. I S. 2142), lastly changed by Article 6 of the regulation from October 22nd, 2003 (BGBl. I S. 2085), such light bulbs have to have an approval mark, which starts with a sine wave and the letter 'K'. Complementary to the StVZO the "Technische Anforderungen (TA) an Fahrzeugteile as per § 22a StVZO" technological requirements for vehicle parts refers to DIN specifications.

German vehicle bulbs per DIN

Category	Nominal power	Filaments	Cap (Base)	Comments	Image
Form K (DIN 72601, Part 4)	6V, 10W	1	SV8,5-8	11x41mm
Form K (DIN 72601, Part 4)	12V, 10W	1	SV8,5-8	11x41mm
Form K (DIN 72601, Part 6)	6V, 18W	1	SV8,5-8	15x41mm
Form K (DIN 72601, Part 6)	12V, 18W	1	SV8,5-8	15x41mm
Form K (DIN 72601, Part 6)	24V, 18W	1	SV8,5-8	15x41mm
Form R (DIN 72601, Part 6)	6V, 18W	1	BA15s
Form R (DIN 72601, Part 6)	12V, 18W	1	BA15s
Form R (DIN 72601, Part 6)	24V, 18W	1	BA15s
Form S (DIN 72601, Part 7)	6V, 18/5W	2	BAY15s
Form S (DIN 72601, Part 7)	12V, 18/5W	2	BAY15s
Form S (DIN 72601, Part 7)	24V, 18/5W	2	BAY15s

United States

Internationally-approved bulb designs are not necessarily allowed in the United States, which does not recognize international ECE Regulations. Bulb types allowed for use in headlamps in the United States are individually approved by the National Highway Traffic Safety Administration

National Highway Traffic Safety Administration

The National Highway Traffic Safety Administration is an agency of the Executive Branch of the U.S. government, part of the Department of Transportation...

 (NHTSA) after a manufacturer submits all critical data on the bulb required by the provisions of 49CFR564

Code of Federal Regulations

The Code of Federal Regulations is the codification of the general and permanent rules and regulations published in the Federal Register by the executive departments and agencies of the Federal Government of the United States.The CFR is published by the Office of the Federal Register, an agency...

. The allowable types of bulbs (officially known as "replaceable light sources") are filed in a NHTSA Docket.

Headlights

Category	Cap (Base)	Filaments	Nominal power @ 12.8v (High/Low beam where applicable)	Comments	Image
HB1 (9004)	P29t	2	65/45W
HB2 (9003)	P43t-38	2	60/55W	European H4 w/strict geometric tolerance & lower max output
HB3 (9005)	P20d (90°)	1	65W
HB3A (9005XS)	P20d (straight)	1	65W	Same as HB3 exc. 180° straight base
HB4 (9006)	P22d (90°)	1	55W
HB4A (9006XS)	P22d (180° straight)	1	55W	Same as HB4 exc. 180° straight base
HB5 (9007)	PX29t	2	65/55W
H13 (unofficially "9008")	P26t	2	65/55W

Many types of lamps are used for turn signal, brake lamps, side and clearance marker lamps, and interior lamps. Type numbers standardized by ANSI

Ansi

Ansi is a village in Kaarma Parish, Saare County, on the island of Saaremaa, Estonia....

 are used by manufacturers to identify bulbs with the same specifications. Bases may be bayonet-type with one or two contacts, plastic or glass wedge, or other types such as wire-loop or metal caps used on tubular lamps. Screw-base lamps are never used in automobile applications due to their loosening under vibration. Signal lamps may have clear bulbs, or may be coated red or amber to provide extra contrast in brake-lamp and turn-signal applications.

Others

Category	Cap (Base)	Filaments	Nominal power	Comments	Image
PC194	?	1	14V?/3.78W, ?	Used on circuit boards for e.g. dash lights

Other countries

Others

Category	Cap (Base)	Filaments	Electrical Characteristics	Comments	Image
H3C	1	6V/55W, 12V/55W, 24V/70W	Japan (USA for unregulated auxiliary lamps only)

See also

• Automotive lighting
  Automotive lighting
  The lighting system of a motor vehicle consists of lighting and signalling devices mounted or integrated to the front, sides, rear, and in some cases the top of the motor vehicle...
  
  
• ECE Regulations
• Federal Motor Vehicle Safety Standard 108
  Federal Motor Vehicle Safety Standard 108
  Federal Motor Vehicle Safety Standard 108 regulates all automotive lighting, signalling and reflective devices in the United States. Like all other Federal Motor Vehicle Safety Standards, FMVSS 108 is administered by the United States Department of Transportation's National Highway Traffic Safety...
  
  
• Headlamp
  Headlamp
  A headlamp is a lamp, usually attached to the front of a vehicle such as a car or a motorcycle, with the purpose of illuminating the road ahead during periods of low visibility, such as darkness or precipitation. Headlamp performance has steadily improved throughout the automobile age, spurred by...
  
  
• Sealed beam
  Sealed beam
  A sealed beam is a type of lamp that includes a reflector and filament as a single assembly, over which a front cover of clear glass, is permanently attached. Previously, automotive headlamps used a separate small bulb and reflector covered with a ribbed lens to avoid glare from the filament. This...