Round five of the 2015 FIA World Endurance Championship has reached the three-hour, halfway mark. Here's how the opening three hours of the Six Hours of Circuit of The Americas panned out.
First Hour
The No. 18 Porsche 919 Hybrid got by the polesitting sister car, the No. 17 at the hands of Neel Jani, in the opening corner after the race went green and the clock began counting down from six hours.
Emmanuel Collard of the No. 83 AF Corse Ferrari of the GTE-Am category was issued a drive through penalty after jumping the start.
Within the opening five minutes, the battle for fourth overall between Sébastien Buemi of the No. 1 Toyota Racing entry and André Lotterer in the Audi Sport Team Joest heated up with Lotterer in the Audi eventually getting by.
In LMP2, Ryan Dalziel, at the wheel of the No. 30 Extreme Speed Motorsports Honda-powered Ligier JS P2 moved into second ahead of Gustavo Yacaman in the No. 28 G-Drive Racing Nissan-powered Ligier JS P2, with Nicolas Lapierre of the No. 47 Oreca 05 Nissan of KCMG moving past Ryan Dalziel later in the hour for second position.
Just before the end of the hour the GTE-Pro and GTE-Am cars began their pit cycles under green.
The first hour of the race closed with no full course yellows.
Second Hour
The beginning of the second hour started with the GTE-Pro and GTE-Am cars completing their pit stops and driver changes.
The GTE-Am polesitting No. 77 Dempsey-Proton Racing Porsche 911 RSR was brought in by Patrick Long for service and a driver change, with Long handing it over to Patrick Dempsey who got back on track still as the leader of the GTE-Am category.
Dalziel led in LMP2 at the beginning of the hour, however shortly after the start of the hour Richard Bradley in the No. 47 KCMG Oreca 05 Nissan passed him for the class lead.
Early in the second of six hours, there was contact between the No. 50 Larbre Competition Corvette and the No. 7 Audi that saw the Corvette spin, followed by a spin by Gustavo Yacaman in the No. 28 G-Drive Ligier.
About 20 minutes into the second hour of the race, a few of the LMP2 cars came into the pits, including the No. 30 ESM Ligier in which Dalziel completed his stint and handed it over to Scott Sharp. The No. 28 G-Drive entry was brought in by Yacaman and the No. 47 of KCMG built a decent lead of about 20 seconds as the second hour reached its halfway mark.
The leading No. 17 Porsche at the hands of Brendon Hartley earned almost a near 20-second lead over the sister car driven then by Marc Lieb. The No. 8 Audi ran in third, over 33 seconds behind the leader with the No. 7 another 40 seconds back. At the halfway mark of this second hour, the Toyotas were struggling to remain on the lead lap.
With about 20 minutes left in the second hour, the cars began their pit stop cycles again. The Audis changed tires, but no driver changes.
The No. 18 Porsche came in for full service, including driver change from Lieb to Romain Dumas. The No. 17 leading Porsche also did a full stop with Mark Webber climbing back into the car, as planned, meaning Timo Bernhard was yet to pilot the car yet.
The No. 13 of Rebellion Racing also did a full service stop with driver change from Daniel Abt to Alexandre Imperatori after the car spent some time in the garage.
With about 10 minutes remaining in the second hour, the No. 2 Toyota did its full service pit stop with driver change; Mike Conway taking over for Stéphane Sarrazin. Anthony Davidson brought the No. 1 Toyota in as well - but missed the pit entrance and had to go around another lap before coming in for full service and handing it over to Kazuki Nakajima.
A full-course caution was issued right before the end of the second hour for Ed Brown of the No. 31 Tequila Patron ESM Ligier flying off the circuit and into the wall at Turn 20.
Near the end of the second hour, the LMP1 positions were the same as they were when the opening hour came to a close.
In LMP2, Richard Bradley still had a lead over Julien Canal and the No. 36 Signatech Alpine Alpine A450B with Nelson Panciatici at the wheel was in third.
The pair of Porsches of Team Manthey remained in the lead of the GTE-Pro class with the No. 51 AF Corse Ferrari in third.
Third Hour
The final hour of the opening half of the race saw the yellow from Brown's high-speed incident at Turn 20 carry over. Later on in the hour, Ed Brown was taken to the infield medical center to be checked out; he was cleared and is okay.
Meanwhile, several cars came in to do their pit stops under yellow.
Green flag racing returned about 15 minutes into the third hour, with a great battle for fourth in the GTE-Am class taking place between Rui Aguas of the No. 83 AF Corse Ferrari F458 Italia and Earl Bamber of the No. 88 Abu Dhabi-Proton Racing Porsche 911 RSR. Patrick Dempsey kept the GTE-Am lead in the No. 77 Dempsey - Proton Porsche with the No. 96 Aston Martin in second and the No. 83 AF Corse Ferrari in third. There was no change in the LMP2 positions immediately after the race went back to green.
The sun went down as the third hour came to a close bringing cooler temps to the track near Austin, Texas. The first two hours saw immense tire degradation due to the heat; teams may be able to stretch their tires our a little longer into the later hours.
About halfway through the third hour, there was not much action in regards to lead changes; Porsche's Mark Webber remained at the front with a lead of over 40 seconds.
Near the end of the hour the No. 2 Toyota Racing LMP2 and the No. 88 Abu-Dhabi Proton Racing cars came together, causing Mike Conway at the controls of the Toyota to lose control and make heavy contact with the inside wall, bringing out a full-course caution.
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Moni Elysium is a writer for the VAVEL USA Racing section. Follow her on Twitter at @Monielysium.