With running in the morning session hampered by heavy rain AT&T Williams driver Kazuki Nakajima would return to the cockpit today to take over the FW30 from Nico Rosberg. This was the last day in the teams four day test, with the team would continuing their development of the FW30 in preparation for the Spanish Grand Prix.

Kazuki would make up for the lack of running in the morning by covering sixty two laps of the Circuit de Catalunya. He would set the sixth fastest time of the day with a 1m:24.927.

Kazuki would be the cause of the only red flag of the day when his Toyota engine let go late in the date at the first corner.

Dickie Stanford, Test Team Manager: "Kazuki took over from Nico today for the last day of the test and concentrated on set-up for the Barcelona race. Unfortunately, we lost a lot of track time this morning due to torrential rain which prevented any of the teams covering any mileage until after lunch. We were able to get some running in this afternoon using the intermediates and then we covered a few laps on the dry tyres to complete our prep work for the race."

Kazuki Nakajima: "For me, day one of the test this week was spent testing the slick tyres for next year and was quite interesting. Nico then covered days two and three and I came back today to work on set-ups for the race. Unfortunately, we had a lot of rain in the morning so couldn't get out of the garage, but managed some runs this afternoon. It wasn't as much time as I would have liked, and the conditions were constantly changing, but we've done some good work and I'm looking forward to coming back for the race next weekend."