The prototype, based on vehicle technology, uses a camera and radar to detect obstacles.
Ford said it could prevent kids from causing chaos in supermarkets by crashing trolleys.
Parenting expert Tanith Carey said: "Parents often dread supermarket shopping because they are trying to get a job done and kids just want to play."
Ms Carey, author of What's My Child Thinking? Practical Child Psychology For Modern Parents, said: "Children love to copy adults and experiment with feeling more in control.
"When they push a trolley, to their minds, it's like they are behind the wheels of a car - with long, wide supermarket aisles as their racetrack."
The car maker said it was has no plans to make the self-braking trolley experiment available to the public.
It said the invention was "just a prototype for the time" to highlight the benefits of such technology in cars.
The device, pre-collision assist technology, uses a forward-facing camera and radar to detect vehicles, pedestrians and cyclists in the road, and automatically applies the brakes if the driver does not respond to warnings.
Spokesman Anthony Ireson said: "The technology can help our customers avoid accidents or mitigate the effects of being involved in a collision.
"We thought that showing how similar thinking could be applied to a shopping trolley would be a great way to highlight what can be a really useful technology for drivers."