IG-L Speed Limits in Austria: What the Sign Means and Who It Applies To

If you drive on Austrian motorways, you will sooner or later see a speed-limit sign with “IG-L” underneath it. This is not an ordinary traffic restriction: it is based on the federal law protecting air quality. Here is what you need to know in 2026.

What is an IG-L speed limit?

IG-L is the abbreviation for Immissionsschutzgesetz-Luft, an Austrian federal law intended to reduce air pollution. Under Section 14 of the law, the provincial governor (Landeshauptmann) may impose speed limits in designated remediation areas (Sanierungsgebiet).

The reason for slowing down is therefore not necessarily accident risk or road conditions. The aim is to reduce the amount of pollutants emitted by traffic. The restriction is nevertheless just as mandatory as any other speed limit.

How to recognise an IG-L restriction

An IG-L speed-limit sign always has an additional sign (Zusatztafel) with one of the following inscriptions:

• “Immissionsschutzgesetz-Luft”, or
• “IG-L”.

When you see this additional sign, you know that the speed limit has been introduced for environmental reasons.

Permanent and variable IG-L limits

There are two types of IG-L speed restriction:

• Permanent: applies continuously in remediation areas.
• Variable: may apply on motorways and expressways (Schnellstraße) and is activated depending on air quality.

For a variable restriction, electronic signs display the current limit. The same section of road may therefore have an IG-L limit on one day but not on another. Always follow the speed shown on the current sign.

What about vehicles with green number plates?

The green number plate (E-Kennzeichen) is a special registration plate for purely electric or hydrogen fuel-cell vehicles. Vehicles in categories L, M1, M2, M3, N1, N2 and N3 can receive it.

• Green plates have been available in Austria since 1 April 2017, and they are voluntary.
• Owners of electric and fuel-cell vehicles registered earlier can also change to a green number plate.
• On motorway and expressway sections, the IG-L restriction does not apply to vehicles with green number plates, but only where a separate information sign (Hinweisschild) indicates this exemption.
• In that situation, the vehicle may travel at the speed otherwise permitted on that section.

Important: The exemption is linked to the registration plate. If the sign indicating the exemption is not displayed, the IG-L restriction also applies to vehicles with green number plates.

Tyrol: permanent 100 km/h limits on sections of the A12 and A13

Tyrol is the best-known example of IG-L restrictions. The province introduced increasingly strict measures:

• 2006: 100 km/h applied during the winter half-year on some sections of the A12.
• November 2007: a variable restriction depending on air quality was introduced on the A12 between Kufstein/Ebbs and Unterperfuss.
• 11 February 2009: the variable restriction also applied between Imst and Zams.
• 20 November 2014: a permanent 100 km/h limit came into force on some sections of the A12 and A13.

The permanent restriction was introduced because the annual nitrogen dioxide (NO2) limit value could not be met at several measuring stations beside the motorways, including Vomp and Kundl along the A12 and Mutters-Gärberbach along the A13. With the introduction of the permanent 100 km/h limit, the previous Tyrolean regulation dependent on air quality ceased to apply.

Which normal speed limits can IG-L replace?

IG-L restrictions override the usual Austrian speed limits. For cars and motorcycles with a permitted maximum gross weight of up to 3500 kg, the general limits are:

• Built-up area (Ortsgebiet): 50 km/h
• Outside built-up areas (Freiland): 100 km/h
• Expressway (Autostraße): 100 km/h
• Motorway (Autobahn): 130 km/h

Additional rules may also apply, such as night-time speed limits on certain motorways. If an IG-L sign displays a lower limit, that displayed limit must be followed.

Frequently asked questions

Who decides where an IG-L restriction applies?

The provincial governor (Landeshauptmann) decides this by regulation. As a result, the locations and form of the restrictions can differ between provinces.

Is an IG-L sign always active?

Not necessarily. The restriction may be permanent, but on motorways and expressways it may also be variable. In that case, the current value shown on the electronic sign is decisive.

Can hybrid vehicles use the exemption?

The green number plate is available only for purely electric or hydrogen fuel-cell vehicles. The exemption is linked to this registration plate.

Does the exemption apply to an electric vehicle with a black number plate?

The exemption applies to vehicles with green number plates. Since the green number plate is voluntary, the exemption cannot be claimed with a black number plate.

Practical steps when driving under an IG-L restriction

1. Check beneath every speed-limit sign for the words “Immissionsschutzgesetz-Luft” or “IG-L”.
2. On motorways and expressways, watch the electronic signs because the limit may be variable.
3. If you drive a purely electric or hydrogen fuel-cell vehicle, check whether it has a green E-Kennzeichen.
4. Look for a separate Hinweisschild confirming that green-number-plate vehicles are exempt.
5. If no exemption sign is displayed, follow the IG-L limit even if your vehicle has a green number plate.
6. When in doubt, follow the speed currently displayed on the sign rather than relying on the usual motorway limit of 130 km/h.