Marco Andretti topped the timesheets on Friday with the best lap in the first practice session on the streets of Long Beach on Friday morning.

His time of 1:17.2298s (91.737mph) on the 1.968-mile, 11-turn temporary street circuit was some six seconds off what teams will be expecting to achieve here based on last year's lap times, as conditions were cold and breezy with the track itself still wet at key points and corners at the start of the practice session from earlier rain.

While a dry line emerged by the end of the hour it was nonetheless still treacherous enough to catch out both Takuma Sato (a spin at turn 10) and Simona de Silvestro (a heavier impact into the tyre wall at turn 8) in separate incidents and bring out a red flag six minutes from the end of the planned running time.

Rubens Barrichello put in the most laps in the session (19 in total) as he tried to get to grips with the tricky, technical street course, but several cars opted not to run at all in the morning. Both Dale Coyne Racing cars stayed in the garage having work carried out on them, and all the Ganassi drivers except for Scott Dixon also sat out the session in expectation of warmer, drier conditions on Saturday and Sunday.

Dario Franchitti did venture out in the second hour-long afternoon practice session, but as rain had arrived during the intervening Firestone Indy Lights practice session there was little hope of setting any competitive time.

With the rain increasing during the afternoon, conditions worsened and when Scott Dixon decided to come out for a lap late in the session he promptly aquaplaned into a heavy right side hit into the wall at turn 1. Unsurprisingly no one else came out of pit road after that, leaving the two Ganassi drivers the only ones to brave the afternoon conditions.

"I just aquaplaned out there," he admitted. "I saw a puddle and thought it was really no big deal ... I hit the puddle and couldn't turn."

Meanwhile Lotus Dragon Racing's Katherine Legge and Dreyer & Reinbold Racing's Oriol Servia were both added to the growing list of cars that will be hit by ten-place grid penalties for unscheduled engine changes, after both cars needed to swap in new Lotus power plants.

With the already announced engine change for Legge's team mate S?bastien Bourdais and the entire 11-car Chevrolet line-up, that brings the total to 14 of the 26 cars now subject to a penalty on Sunday.

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