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Road rules abroad

What changes when you cross the border

United States → Ireland

Driving in Ireland when you know the United States

Differences first, worst-to-get-wrong first. Rules that match are folded away at the bottom.

What's different (1)

Whether you need an International Driving Permit

Critical
United States · homeDepends on where your licence is fromDepends on your licence country and on the state. Not every state requires an International Driving Permit, and the US does not issue them to visitors — get one at home before travelling. Check the destination state's motor vehicle department.Checked 3 Aug 2026
Ireland · destinationNot requiredA valid licence in English or Latin script is enough for visits. Licences in other scripts should be carried with an International Driving Permit.Checked 6 Aug 2026 · official source

Known on one side only (15)

Which side of the road you drive on

United States · homeNot yet verified
Ireland · destinationLeftChecked 6 Aug 2026 · official source

Speed limit on the motorway

Varies by region
United States · homeNo single national answer:
Texas75 mph — about 121 km/hThe commission may set 80 or 85 where the road is designed for it — the highest signed limits in the country.Checked 3 Aug 2026
California65 mph — about 105 km/hThe general maximum unless 70 is posted.Checked 3 Aug 2026
Ireland · destination120 km/hChecked 6 Aug 2026 · official source

Speed limit on country roads

Varies by region
United States · homeNo single national answer:
Texas70 mph — about 113 km/hThe statutory maximum unless the commission raises it for a numbered highway.Checked 3 Aug 2026
California55 mph — about 89 km/hOn a two-lane undivided highway, and for anything towing a trailer.Checked 3 Aug 2026
Ireland · destination80 km/hRegional (R-numbered) roads. National (N) roads are 100. Small local (L-numbered) roads dropped to 60 in February 2025 — older guidance still says 80.Checked 6 Aug 2026 · official source

Speed limit in towns and cities

Varies by region
United States · homeNo single national answer:
Texas30 mph — about 48 km/hThe default through an urban district unless zoned otherwise.Checked 3 Aug 2026
Ireland · destination50 km/hMore and more town cores and housing areas are signed 30.Checked 6 Aug 2026 · official source

How much alcohol you may have in your blood

Varies by region
United States · homeNo single national answer:
California0.08 % BAC — about 80 mg/100mlChecked 3 Aug 2026
Ireland · destination50 mg/100mlMuch stricter than Great Britain's 80 — a pint can put you over here.Checked 6 Aug 2026 · official source

Alcohol limit for drivers who passed their test recently

United States · homeNot yet verified
Ireland · destination20 mg/100mlLearners and drivers in their first two years — effectively zero.Checked 6 Aug 2026 · official source

Holding a phone while driving

Varies by region
United States · homeNo single national answer:
CaliforniaNot allowedChecked 3 Aug 2026
Ireland · destinationNot allowedCourt fines can reach 2,000 euros.Checked 6 Aug 2026 · official source

Turning at a red light

Varies by region
United States · homeNo single national answer:
CaliforniaAllowedAfter a complete stop at the limit line, yielding to pedestrians, unless a NO TURN ON RED sign is posted.Checked 3 Aug 2026
Ireland · destinationNot yet verified

Who must wear a seatbelt

United States · homeNot yet verified
Ireland · destinationEveryone, in every seatChecked 6 Aug 2026 · official source

Height below which a child needs a child seat

United States · homeNot yet verified
Ireland · destination150 cmOr under 36 kg. Licensed taxis are exempt.Checked 6 Aug 2026 · official source

How you pay for motorways

United States · homeNot yet verified
Ireland · destination
  • Toll booths
  • Electronic tolls with no barriers
Most tolls are barriers taking cards or cash. The big exception is Dublin's M50: no barriers, cameras only — pay online or at a Payzone shop by 8pm the NEXT day, or penalties go to the rental company. Rental cars often carry a tag; ask when you collect the car.Checked 6 Aug 2026 · official source

Alcohol limit for professional drivers

Varies by region
United States · homeNo single national answer:
California0.04 % BACCommercial vehicles, and passenger-for-hire driving.Checked 3 Aug 2026
Ireland · destinationNot yet verified

How long you may drive on your own licence

United States · homeNot yet verified
Ireland · destination12 monthsAs a visitor, on your own country's licence.Checked 6 Aug 2026 · official source

Hands-free phone calls

Varies by region
United States · homeNo single national answer:
CaliforniaAllowed, with restrictionsAdults may use hands-free mode. Drivers under 18 may not use a phone at all.Checked 3 Aug 2026
Ireland · destinationAllowedChecked 6 Aug 2026 · official source

Emergency number

United States · home911Checked 3 Aug 2026
Ireland · destinationNot yet verified