Nicholas Latifi says a lack of confidence at the wheel is why he's been left without a place in Formula 1.
The Canadian became known as the driver who normally brought up the rear during his three seasons with Williams.
"I just couldn't find the confidence that was really needed," Latifi, 27, told Motorlat.
"And the car was the slowest on the grid, so that's one thing. But I never really felt comfortable pushing the car to its limits, which was also the case in previous years.
"So that's also a bit of a Williams trait for how the car has been."
Latifi, whose billionaire father Michael sponsored Williams via the Sofina brand, says the situation was worsened because his teammates coped better with the car.
"I think guys like George (Russell) and Alex (Albon) struggled less with that and were able to adapt to it better," he said.
"I think whether it's karts, entry-level formula cars or sedans, a driver always wants to have confidence in their car but it becomes much more important the closer you get to Formula 1.
"Obviously with the amount of horsepower we have and the amount of downforce these cars generate, if you don't trust what the car beneath you is doing, you can't predict what it's going to do."
Latifi insists, however, that one of his strengths was tyre management.
"The feeling of handling tyres is one of my strengths," he said. "I generally feel like I can be consistent, go to the limit of the tyre but not too much.
"This year it was a bit different because sometimes I was quite behind in race pace, but that's a different story."
