It was a fear of being run over by a lorry while out cycling one evening that gave Emily Brooke the brainwave to create an innovative new bike light.
Then a design student in her final year at Brighton University, she was trying to develop a new bicycle safety product, but struggling to come up with a standout idea.
Inspiration came when cycling down a busy city centre street Ms Brooke, now 29, realised that the driver of the lorry in front of her couldn't see her, and that if he was to suddenly turn left she would be "squished".
Thinking about the problem, Ms Brooke came up with the idea of creating a front bike light which also projected a laser image of a bicycle 5m (16ft) ahead to warn motorists that there was a cyclist in their blind spot.
Developing the idea as her main university project, she built a working prototype and got a patent to prevent any copycat producers.
After graduating from Brighton in 2011, she officially launched her business - Blaze - a year later in London, and continued development work on the light.
The Blaze Laserlight hit the marketplace last year, and within months had sold more than 3,000 units.
Yet despite her continuing success, which includes attracting investment from the family of billionaire Sir Richard Branson, Ms Brooke says she doesn't consider herself to be an entrepreneur.
Instead she describes herself as "a crazy, optimistic and driven person, fortunate enough to be making her vision a reality".
For someone who runs a bike accessory business you might imagine that Ms Brooke is a lifelong cyclist.
Instead she only caught the cycling bug when she was 25, following the sudden death of a male friend.
In his memory, Ms Brooke and a friend decided to cycle the length of the UK from Lands End to John O'Groats to raise money for charity.
It was then that she fell in love with cycling. But more than that, she says experiencing such a profound loss made her want to live her life to the full.
She says it made her determined not follow the corporate rat race, and instead she resolved to start her own company.
With the inspiration for the light coming from cycling down a busy road at night, the idea for her product and business was born.
Before Sir Richard's family made an investment last year, Blaze was back in 2012 one of the first UK companies to raise funds by crowdfunding.
It secured £60 contributions from members of the public, in exchange for promising to post them the lights as soon as possible after they had gone into commercial production.
Thanks to excitement about the lights due solely to positive word of mouth, Blaze was able to raise £55,000 via crowdfunding website Kickstarter, almost three times its £20,000 target.
Ms Brooke says: "We ran the crowdfunding the month Kickstarter launched in the UK, and it was nerve wracking because the UK really didn't understand what Kickstarter was.
"But people started talking about us straight away and we were amazed and surprised as the pledges started rolling in.
"It was the best way I could prove the concept - prove people liked the idea, that they would pay for it, before I went and spoke to manufacturers, retailers, investors, etc."
Ms Brooke's target was £25,000. In less than five days she had raised £20,000 and eventually made £55,000 from the Kickstarter project.
It was enough money for a final design to be agreed upon, and for production to start in 2014 in China.
Sir Richard made his investment after he was told about the light by his children, and Emily was invited to meet him.
She so impressed the billionaire that he joined with global investment firm Index Ventures to put in a combined £300,000.
Stocked in the UK by nationwide chain Evans Cycles, Blaze has also sold its light to 47 other countries via its website. The light retails for £125.
This is expensive for a bike light, but Ms Brooke says it reflects the quality of its components.
As sales continue to grow, and with plans to launch a rear bike light later this year, it is a busy working life for Ms Brooke and her small team of staff based in their office in East London.
For other young people thinking of setting up their own company, she cautions that they have to give it all their time, and make a lot of personal sacrifices.
"I feel like I'm not the best or most present daughter, sister, friend. I'm often either late or not appearing at all to events which I wish I could do," she says.
"I often get to the weekend and realise I've made no plans. I travel so much that my friends just think I'm not around."
Still, Ms Brooke is adamant that despite the challenges of managing her work-life balance, she is passionate about what she does.
"I never get that Monday morning hump. This is my life and I'm lucky to be building something I believe in."