Council bosses have defended signage on Cambridgeshire's guided busway after a lorry accidentally drove along it.
The 44-tonne Metcalfe's truck from Hawes in North Yorkshire was spotted by a dog walker as it drove about 300m (985ft) along the concrete track.
Company owner Peter Metcalfe said his driver had "relied too heavily on his sat-nav" and had been reprimanded.
A council spokesman said there were "extensive warning signs" but would look in to comments about the sat-nav.
Graham Hughes, director of strategy and development at the council, said: "There are clear and prominent signs on all the entry points.
"To be honest, we do struggle to understand how this driver, in broad daylight, managed to get on to the busway."
Mr Metcalfe apologised to the council but said the driver told him his navigation system did not give any warning about the concrete tracks, which guide buses along parts of Cambridgeshire.
"We don't usually deliver around the Longstanton area, or Cambridgeshire, so it wasn't something the driver had ever come across before," he said.
"However, I do think some people rely too heavily on sat-navs instead of reading the road signs."
Mr Hughes added: "Luckily nothing happened, no one was injured and the tracks weren't damaged, but it's a dangerous place to be unless you're a bus.
"We work closely with sat-nav companies but we will certainly be following up on that," he said.
"Drivers of all vehicles need to have a bit of common sense. Clearly this lorry driver didn't.
"He actually must have tried very hard to manoeuvre on to the busway. It's obviously not a regular road and we're quite puzzled how he managed it."
The council warned Mr Metcalfe that the company could be fined up to £1,000 if it happened again.