Sensors on some cars treated the rural road feature as an obstruction and slammed on the automatic brakes to avoid a collision.
The local council said the grid had been "causing a very real danger to road users" on Hill Road in Minehead.
A spokesman for the council said the grid had to be replaced following a "number of incidents of cars leaving the road" but "thankfully there have been no serious collisions".
He explained that highway teams spent a month raising 90ft of road and redesigning carriageway approaches to create a “virtually smooth ride across the grid.”
Dave Peake, the council's highways service manager, said the modern problem was something that would "never ever have been considered" when the grid was installed "many years ago".
"It's quite a steep hill and the cattle grid's got to be reasonably level," he said.
"But the problem was this sudden change in gradient. Some of the car's sensors were detecting this as a wall so automatically applied the brakes.”
Prof Andrew Graves, automotive analyst at the University of Bath, said features like brake assist have been around since the 1980s but "a lot of this technology is not clever enough at the moment".
"Modern cars are pretty good at doing this but they're still not perfect and sometimes they send out a very confused message."
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In another story from 2019, an automated car failed to brake in time when it didn’t identify 49-year-old Elaine Herzberg as a pedestrian. Sadly, the crash proved fatal.
Although the backup driver was watching a TV programme at the time, software flaws were cited in the US National Transport Safety Board’s (NTSB) final report.
However, in most cases automatic braking is a crucial safety system. Just last year, automated safety technology saved the lives of two families when a tree suddely crashed down on a road in stormy conditions.
Staggering photos showed how the two Tesla vehicles avoided a fatal collision when their automatic brakes were applied at the same time on the A31 in Dorset.
Kitty McConnell, passenger in one of the electric cars, later tweeted: “Hey @elonmusk Your car saved my life.. and by boyfriends.. and my mothers.. [sic] and a family of five.”
