World Forum for Harmonization of Vehicle Regulations

The World Forum for Harmonization of Vehicle Regulations is a working party (WP.29) of the United Nations Economic Commission for Europe (UNECE). It is tasked with creating a uniform set of regulations for vehicle design to facilitate international trade.

The forum works on regulations covering vehicle safety, environmental protection, energy efficiency and theft-resistance.

1958 Agreement
The core of the Forum's work is based around the 1958 Agreement, formally titled "Agreement concerning the adoption of uniform technical prescriptions for wheeled vehicles, equipment and parts which can be fitted and/or be used on wheeled vehicles and the conditions for reciprocal recognition of approvals granted on the basis of these prescriptions". This forms a legal framework whereby participating countries agree a common set of ECE Regulations for type approval of vehicles and components. When an item is type approved for a regulation by one participating country, then the approval is accepted by all other participating countries.

Originally, the 1958 Agreement allowed participation of ECE member countries only, but in 1995 the agreement was revised to allow non-ECE members to participate.

List of participating countries
, the participants to the 1958 Agreement, with their ECE country code, are:

Most countries, even if not formally participating in the 1958 agreement, recognise the ECE Regulations and either mirror the ECE Regulations' content in their own national requirements, or permit the use and importation of ECE-approved vehicles, or both. The USA and Canada are the two significant exceptions; there ECE regulations are generally not recognised and ECE-compliant vehicles and equipment are not authorised for import, sale, or use in the USA.

Type approval
The 1958 Agreement operates on the principles of type approval and reciprocal recognition. Any country that accedes to the 1958 Agreement has authority to test and approve any manufacturer's design of a regulated product, regardless of the country in which that component was produced. Each individual design from each individual manufacturer is counted as one individual type. Once any acceding country grants a type approval, every other acceding country is obliged to honor that type approval and regard that vehicle or item of motor vehicle equipment as legal for import, sale and use. Items approved as meeting an ECE Regulation are marked with an E and a number, within in a circle. The number indicates which country approved the item, and other surrounding letters and digits indicate the precise version of the regulation met and the type approval number, respectively.

Although all countries' type approvals are legally equivalent, there are real and perceived differences in the rigour with which the regulations and protocols are applied by different national type approval authorities. Some countries have their own national standards for granting type approvals, which may be more stringent than called for by the ECE regulations themselves. Within the auto parts industry, a German (E1) type approval, for example, is regarded as a measure of insurance against suspicion of poor quality or an undeserved type approval.

List of ECE Regulations
, there are 123 ECE Regulations. Most regulations cover a single vehicle component or technology. A partial list of current regulations applying to passenger cars follows (different regulations may apply to heavy vehicles, motorcycles etc).

General lighting

 * R3 — Retroreflecting devices
 * R4 — Illumination of rear registration plates
 * R6 — Direction indicators
 * R7 — Front and rear position lamps, stop lamps and end-outline marker lamps
 * R19 — Front fog lamps
 * R23 — Reversing lights
 * R37 — Filament lamps (bulbs) (See: Automotive lamp types)
 * R38 — Rear fog lamps
 * R48 — Installation of lighting and light-signalling devices
 * R77 — Parking lamps
 * R87 — Daytime running lamps
 * R91 — Sidemarker lamps
 * R119 — Cornering lamps
 * R123 — AFS lamps

Headlamps

 * R1 - Headlamps emitting an asymmetrical passing beam and/or a driving beam, equipped with R2 or HS1 bulbs (superseded by R112, but still valid for existing approvals)
 * R5 - Sealed Beam headlamps emitting an asymmetrical passing beam and/or a driving beam
 * R8 - Headlamps equipped with replaceable single-filament tungsten-halogen bulbs (superseded by R112, but still valid for existing approvals)
 * R20 - Headlamps emitting an asymmetrical passing beam and/or a driving beam and equipped with halogen double-filament H4 bulbs (superseded by R112, but still valid for existing approvals)
 * R31 — Halogen sealed beam headlamps emitting an asymmetrical passing beam and/or a driving beam
 * R45 — Headlamp cleaners
 * R98 — Headlamps equipped with gas-discharge light sources
 * R99 — Gas-discharge light sources for use in approved gas-discharge lamp units of power-driven vehicles (See: Automotive lamp types)
 * R112 — Headlamps emitting an asymmetrical passing beam and/or a driving beam and equipped with filament bulbs
 * R113 — Headlamps emitting a symmetrical passing beam and/or a driving beam and equipped with filament bulbs

Instrumentation/controls

 * R35 — arrangement of foot controls
 * R39 — speedometer equipment
 * R46 — rear-view mirrors
 * R79 — steering equipment

Safety

 * R11 — door latches and door retention components
 * R13-H — braking (passenger cars)
 * R14 — safety-belt anchorages
 * R16 — safety-belts and restraint systems
 * R27 — advance-warning triangles
 * R42 — front and rear protective devices (bumpers, etc.)
 * R43 — safety glazing materials and their installation on vehicles
 * R94 — protection of the occupants in the event of a frontal collision
 * R95 — protection of the occupants in the event of a lateral collision
 * R116 — protection of motor vehicles against unauthorized use

Environmental/performance

 * R10 — electromagnetic compatibility
 * R24 — Engine power measurement, smoke emissions, engine type approval
 * R51 — noise emissions
 * R68 — measurement of the maximum speed
 * R83 — emission of pollutants according to engine fuel requirements
 * R84 — measurement of fuel consumption
 * R85 — ilectric drive trains — measurement of the net power and the maximum 30 minutes power of electric drive trains
 * R100 — approval of battery electric vehicles with regard to specific requeriments for the construction, functional safety and hydrogen emission.
 * R101 — measurement of the emission of carbon dioxide and fuel consumption
 * R117 — rolling sound emissions of tyres

North America
The most notable non-signatory to the 1958 Agreement is the United States, which has its own Federal Motor Vehicle Safety Standards and does not recognise ECE approvals. ECE vehicles and components therefore cannot be imported or exported between the U.S. and most of the rest of the world without appropriate modifications (federalization). Canada has its own Canada Motor Vehicle Safety Standards, broadly similar to the FMVSS, but Canada does also accept ECE-compliant headlamps and bumpers.

Self-certification
Rather than an ECE-style system of type approvals, the US and Canadian auto safety regulations operate on the principle of self-certification (or autocertification), wherein the manufacturer or importer of a vehicle or item of motor vehicle equipment certifies — i.e., asserts and promises — that the vehicle or equipment complies with all applicable Federal or Canada Motor Vehicle Safety, bumper and antitheft standards. No prior verification is required by a governmental agency or authorised testing entity before the vehicle or equipment can be imported, sold, or used. If reason develops to believe the certification was false or improper — i.e., that the vehicle or equipment does not in fact comply — then authorities may conduct tests and, if a noncompliance is found, order a recall and/or other corrective and/or punitive measures. Vehicle and equipment makers are permitted to appeal such penalties by filing petitions for finding of noncompliance inconsequential to safety.

Regulatory differences
One of the most contentious differences between ECE and U.S. regulations is the design of headlamps; see that article for more information. The Citroën DS article offers a pictorial illustration of US-model vs. ECE-model headlamps during the 1940-1983 era when US regulations required sealed beam headlamps.

It is not currently possible to produce a single car design that meets both ECE and FMVSS approvals, but it is growing easier as both sets of regulations evolve. Given the size of the U.S. vehicle market, and differing marketing strategies in North America vs. the rest of the world, many manufacturers produce vehicles in three versions: North American, rest-of-world right-hand drive (RHD) and rest-of-world left-hand-drive (LHD).

OICA
Organisation Internationale des Constructeurs d'Automobiles (OICA) hosts on its web site the working documents from various United Nations expert groups including World Forum for Harmonization of Vehicle Regulations.