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Road rules abroad

What changes when you cross the border

Australia → United States

Driving in the United States when you know Australia

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

What's different (1)

Emergency number

Good to know
Australia · home000112 also works from mobile phones and reaches the same service.Checked 3 Aug 2026
United States · destination911Checked 3 Aug 2026 · official source

Known on one side only (13)

Which side of the road you drive on

Australia · homeLeftChecked 3 Aug 2026
United States · destinationNot yet verified

Speed limit on the motorway

Varies by region
Australia · homeNot yet verified
United States · destinationNo single national answer:
Texas75 mphThe commission may set 80 or 85 where the road is designed for it — the highest signed limits in the country.Checked 3 Aug 2026 · official source
California65 mphThe general maximum unless 70 is posted.Checked 3 Aug 2026 · official source

Speed limit on country roads

Varies by region
Australia · homeNo single national answer:
New South Wales100 km/hThe default outside built-up areas where no sign is posted. Motorways are signed up to 110.Checked 3 Aug 2026
United States · destinationNo single national answer:
Texas70 mphThe statutory maximum unless the commission raises it for a numbered highway.Checked 3 Aug 2026 · official source
California55 mphOn a two-lane undivided highway, and for anything towing a trailer.Checked 3 Aug 2026 · official source

Speed limit in towns and cities

Varies by region
Australia · homeNo single national answer:
New South Wales50 km/hThe default in built-up areas where no sign is posted. School zones are 40.Checked 3 Aug 2026
United States · destinationNo single national answer:
Texas30 mphThe default through an urban district unless zoned otherwise.Checked 3 Aug 2026 · official source

How much alcohol you may have in your blood

Varies by region
Australia · homeNot yet verified
United States · destinationNo single national answer:
California0.08 % BACChecked 3 Aug 2026 · official source

Whether you need an International Driving Permit

Varies by region
Australia · homeNo single national answer:
New South WalesDepends on where your licence is fromA current overseas licence in English is accepted on its own. A licence not in English needs an English translation or an International Driving Permit.Checked 3 Aug 2026
United States · destinationDepends 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 · official source

Which side you overtake on

Australia · homeRightWhere the limit is over 80 km/h or a sign says keep left, you must not drive in the right lane except to overtake.Checked 3 Aug 2026
United States · destinationNot yet verified

Holding a phone while driving

Varies by region
Australia · homeNo single national answer:
New South WalesNot allowedTouching the phone at all is illegal while driving, including at lights.Checked 3 Aug 2026
United States · destinationNo single national answer:
CaliforniaNot allowedChecked 3 Aug 2026 · official source

Turning at a red light

Varies by region
Australia · homeNo single national answer:
New South WalesOnly where a sign allows itOnly at intersections with a "left turn on red permitted after stopping" sign, after a complete stop, giving way to traffic from the right.Checked 3 Aug 2026
United States · destinationNo 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 · official source

Age below which a child needs a child seat

Varies by region
Australia · homeNo single national answer:
New South Wales7 yearsUnder 7 needs an approved restraint for their age and size; 4 to 7 a forward-facing seat or booster.Checked 3 Aug 2026
United States · destinationNot yet verified

Alcohol limit for professional drivers

Varies by region
Australia · homeNot yet verified
United States · destinationNo single national answer:
California0.04 % BACCommercial vehicles, and passenger-for-hire driving.Checked 3 Aug 2026 · official source

How long you may drive on your own licence

Varies by region
Australia · homeNo single national answer:
New South Wales6 monthsAs a temporary overseas visitor. After that, a NSW visitor licence is needed.Checked 3 Aug 2026
United States · destinationNot yet verified

Hands-free phone calls

Varies by region
Australia · homeNo single national answer:
New South WalesAllowed, with restrictionsFull licence holders may use a cradle or hands-free. Learner and provisional drivers may not use a phone at all.Checked 3 Aug 2026
United States · destinationNo 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 · official source