Three members of the same family, along with a fourth person in another car, have died after a head-on crash on Highway 30 in Chateauguay.

Police say that around 12:15 a.m. Tuesday an 80-year-old man turned onto Highway 30 going in the wrong direction.

He slammed into a car heading west in a collision that killed four people and injured four others.

"They headed down about 300-400 metres before the collision occurred," said Sureté du Quebec officer Daniel Thibaudeau.

Police have identified the dead driver as 80-year-old Pierre-Julien Proulx. His wife, Raymonde Bouchard-Proulx, 82, also died in the crash as did a 14-year-old male relative.

One person in the car hit by Proulx, 56-year-old Carole Downer of Ontario, died in hospital. Earlier reports said she was driving the SUV, but it turns out she was in the front passenger seat.

The four other people in the car from Ontario, three women and a man, survived the crash with serious wounds including broken bones and internal injuries.

Thibaudeau said police are looking at multiple possibilities for the crash, including examining infrastructure in Chateauguay to determine whether the mistake had to do with poor visibility on the highway.

"The coroner who is also assigned to the case is following it and will make recommendations accordingly," he said. "If there is a signage issue that is brought to bear, of course there will be recommendations and corrections that could be brought forth."

Police do not believe that Proulx was intoxicated.

Similar crashes, poor lighting

A similar collision occurred in Chateauguay in September 2015, when an 89-year-old man driving the wrong way on the highway hit an oncoming vehicle, killing both drivers instantly.

Both of these crashes happened within three kilometres of each other.

People who frequently drive in the area said the stretch of highway was notoriously underlit and lacked proper signs.

"It's not lit up at all," said Brigitte Brisson. "It's the third or fourth time that it's happened. You would think by now someone would have figured it out and they would have done something about it. It's an accident that could have been prevented."

Randal Luke said in low light it can be hard to tell which side of Highway 30 to drive on.

"If you're not really paying attention, you'll go straight down the opposite side," he said. "Some people just don't pay attention, they can be distracted by the lights and darkness and just keep going."

Chateauguay's mayor, Nathalie Simon, said she has had close calls over the past four years.

"I personally have a face-to-face encounter with me getting out of the autoroute and a lady tried to get onto the autoroute in the wrong way," said Simon.

"The fact that we see so often people getting in the wrong way means there's a problem of signalization there."

The MNA for the region, Treasury Board president Pierre Moreau, said steps would be taken to improve the lighting and signage beyond the existing "do not enter" sign.

"We won't be waiting for the coroner report to improve whatever thing should be improved to make sure this intersection is safer than it is," said Moreau.