Alcohol, speed and not wearing a seatbelt are being considered as factors in at least three of the deaths on Sunday, January 15.

Mount Burnett teenager Lee Davy was a passenger in a silver ute travelling south on McGregor Road when it hit a power pole about 5.50am. He died at the scene.

The 18-year-old P-plate driver from Koo Wee Rup was taken to Dandenong Hospital with serious injuries and released from hospital late on January 16.

No charges have been laid.

Detective Senior Constable Kelly Carvill of the major collision investigation unit said police were still investigating the circumstances surrounding the crash.

"Without the great amount of information from the public through CrimeStoppers, this wouldn't be possible."

Superintendent Neville Taylor said the four deaths made for "a shocking start to 2012", especially with speed, alcohol and seatbelts potentially involved.

"These are the things that we know kill people on our roads. If that turns out to be the case, this is something that not one Victorian can accept."

He said police were dismayed some drivers were not heeding repeated warnings to drive safely.

"There's a small number of people to whom I have to say, 'What bit of this didn't you understand?'. Because we know drinking and driving kills, we know speeding kills, we know not wearing a seatbelt kills."

Superintendent Taylor said passengers also had to be responsible.

"The message for passengers is: have a think about the car you're getting into.

"If the driver is doing anything but driving responsibly, you've got to speak up, because you have to save your life."

The three other deaths were a male pedestrian hit while crossing crossing Malvern Road in Toorak, a female passenger after her car rolled on Daylesford-Malmsbury Road in Denver, and a male motorcyclist at the intersection of Romsey and Springfield roads in Springfield.

The road toll is 14, four more than the same time last year.

Information to Crime Stoppers, 1800333000 or visit their website here.