Hi Viz is good, especially if you have it around your full torso front and back, with no backpack to cover it.
The idea is to get them to see you from farther away.
That does not mean they will treat you well as they roar by.
Bright lights are better for dusk or 'dark' weather, in busy urban conditions, you need all the help you can get; bright clothes, lights, luck.
You can make it better, but never guarantee complete safety.