A man whose friend was sexually assaulted by an unlicensed minicab driver has developed a mobile phone app to track the route of taxis and minicabs.
Anthony Price, from Bedford, says his free Travel Safer app allows the user to record the registration number of the vehicle they are getting into.
Their journey is then traceable and can also be followed on social media.
Bedfordshire Police said they welcomed safety initiatives but warned people to be careful what they share online.
Mr Price said in 2005 a friend had unknowingly got into an unlicensed vehicle in Peterborough and was sexually assaulted.
She was not able to get the registration details after the attack and the offender was never traced.
"We thought there must be a way to prevent it happening again but at that time the technology didn't exist," he said.
"As soon as technology allowed, we went to the drawing board; now phones have got GPS it's a lot easier to track [people]."
The app captures the user's time and location of check-in and posts the vehicle details to the user's Facebook timeline.
"They can opt out of it being posted on social media, but the journey is still traceable," he said.
"Not only does it give friends and family reassurance their loved one is traceable, it provides accountability to both passengers and drivers of taxi or private-hire vehicles," he said.
Mr Price said any profits made from a "pro" version of the app, which allows passengers to check out of a vehicle and add an image, would go to rape victim charities.