Limo in US crash that killed 20 had failed a road safety test

The first clues are emerging in what caused America's deadliest road crash in a decade.

The limousine that went out of control had failed its latest safety inspection, and its passengers had been texting concerns about the shoddy state of the vehicle.

Eighteen people travelling to a wedding reception in upstate New York died in the crash, as well as two pedestrians.

The crash took place in Schoharie, a town around 250km north of New York City, NBC reported.

This news also follows new information about the driver, who did not have the correct licence to be carrying passengers.

The Washington Post reports one of the 20 victims of the crash had sent a text to her cousin 20 minutes before she was killed, saying the limo was in a "terrible condition".

According to federal records, the company had also taken four vehicles off the road in the past two years.

An investigation is still underway as to what caused the limousine to crash, with several separate police units involved.

This is the deadliest land vehicle accident America has seen since 2005, when a bus full of rest home patients caught fire in Florida whilst escaping Hurricane Rita, killing 23 people.