In the early 1980's Australia was the first country to introduce laws requiring bike riders to wear helmets. {
source} Rosebank Products was the first company to produce helmets designed to government standards and mass-produced and marketed to the public. {
source}
The stackhat was that helmet.
It became an icon of the 80's.
Yellow was the most common colour, but it was also available in white, and in later years, pink.
Mine was white. My brother and sister had yellow. My dad told me the night he brought them home that I had to have white because my head was bigger. Way to go, dad!
I think I've shared before that I grew up in
Horsham, Victoria. We lived on the edge of town, and our school was visible from our front door (as was the local hospital - I had never experienced a power blackout until we left Horsham, because we were on the same power grid as the hospital), but we used to ride our bikes everywhere. I had a
Malvern Star bike, kind of like this one (but it was green)
In 1986 I started high school. School was a 15 minute ride from home, and while I'd struggle to do it these days, it was just part of life, rain, hail or shine, to ride to school every day. There weren't many kids who rode from my side of town, most caught the bus, so I often rode by myself. Kids are cruel, so the helmet was often hanging off the handle bars, instead of on my head.

One day I was riding home, and in the distance I could see a bike rider pulled over by a police car. The rider wasn't wearing his helmet (but I was) and I knew he was being pulled over for not wearing his helmet. I was brought up to respect the authority of the police, so when the car came towards me, then stopped beside me, I was terrified. The officer on the passenger side motioned me over to him, and by the time I hopped off the bike and walked over to him I had tears streaming down my face. I couldn't figure out what I was in trouble for, I was wearing my helmet for a change!
Turns out they wanted to give me a sticker for being a safe bike rider and wearing my helmet! They said, yes, they had given the other rider a warning for not wearing his helmet, but I was doing the right thing, so deserved the safe rider sticker! I was so proud of that sticker when I put it on my bike that night, and it was a long time before I rode without my helmet again!