Police said the woman appeared to have entered the intersection against a red light before she was hit by a car about 6.15am on Friday.

The 36-year-old mother was not wearing a helmet. Headphones found at the scene led police to believe she might have been listening to music.

The crash happened at the intersection of Gourlay Road and the Melton Highway.

Police have interviewed the driver, a 23-year-old Hillside man.

Melton's Inspector Mario Fiorentino said the cyclist was not wearing reflective clothing and had no lights on her bike.

"There are a significant number of incidents with pedestrians and bicycles on our road [and] it is a recurring theme of people not wearing helmets or protective clothing," he said.

The cyclist was the fourth killed on Victorian roads this year.

Inspector Fiorentino said the practice of cyclists and pedestrians wearing headphones was a serious concern because they couldn't hear what was happening around them. It was becoming "endemic".

"It's fine if you're on a running track to listen to music, but if you're in peak-hour traffic with earphones how can you be aware in those circumstances?"

Inspector Fiorentino said every intersection was a potential hazard and people needed to be especially aware around such areas.

Bicycle Network Victoria spokesman Garry Brennan said the timing of the lights at Gourlay Road were not ideal.

"The timing of the traffic lights at that wide intersection can be particularly short, meaning that sometimes a rider cannot get across the entire 40 metres before they turn red."

But VicRoads regional director Nial Finegan said it investigated traffic signal timing at the intersection in June last year.

"On the western side of the intersection, the traffic signals currently have longer green time for pedestrians and bicycle riders than the standard time required. VicRoads considers the traffic signal timing at this location appropriate for the conditions."