A car crash in Florida Monday evening has left two Montrealers in critical condition, and two other people dead.

Dollard-des-Ormeaux’s Joshua Landau was driving northbound on US Highway 1 in the Florida Keys when he hit an oncoming pickup truck.

The passenger of the vehicle was Landau's girlfriend, 30-year-old Randi Deskin.

Highway 1 is known as a very narrow highway with only one lane in each direction.

For reasons that are still under investigation, 32-year-old Landau crossed into the southbound lane around 5:30 p.m. and collided head-on with the pickup.

A friend of the couple says the two went to Florida to celebrate Deskin's 30th birthday, which was earlier this month.

The couple was then airlifted to Ryder Trauma Centre in Miami where they are both in critical condition.

The passengers of the pickup truck were two women from the Keys. One was in her 60s and one was in her 80s. They were both pronounced dead on the scene.

The investigation is ongoing.

Florida highway patrol say 16 people have died on that highway since the beginning of the year.