A massive hit by Tristan Vautier only 16 minutes into the 11th hour brought out the 10th full-course caution of the race while jumbling the strategy of the leaders.
Pitting out of sequence, Spencer Pigot was leading in the No. 55 Team Joest Mazda when Vautier impacted the tire barrier in Turn 17 in the fifth-place No. 90 Spirit of Daytona Cadillac. Vautier got briefly airborne, did a half turn and came to a stop while scattering tires onto the track. Tom Dyer in the No. 69 HART Acura NSX GT3 slammed into the debris, with Markus Palttala in the No. 96 Turner Motorsport BMW M6 GT3 also sustaining damage after hitting debris.
Pigot squeezed between Vautier and the wall to avoid the incident, but ran over debris in the process. All four leaders then pitted under caution. Fillipe Nasr took over the lead in the No. 31 Whelen Engineering Cadillac, followed by Pipo Derani in the No. 22 Tequila Patron ESM Nissan, Renger van der Zande in the No. 10 Konica Minolta Cadillac and Harry Tincknell, who took over for Pigot in the No. 55 Mazda.
Conway had pitted only six minutes into the hour, turning the second-place No. 31 Cadillac over to Felipe Nasr. Lapierre came in while leading on the following lap, installing Pipo Derani in the No. 22 Nissan while returning Pigot to the lead. After the stops, Pigot led Derani by 23 seconds, Nasr 34 seconds behind in third and Jordan Taylor 46 seconds in arrears in fourth. Moments later, Vautier’s incident again jumbled the leaders.
Also prior to the yellow, Patrick Pilet passed Toni Vilander for the GTLM lead, putting the No. 911 Porsche 911 RSR back in front after hounding the No. 62 Ferrari for many circuits. Nick Tandy returned to the No. 911 Porsche under the caution, followed by Pier Guidi in the No. 62 Ferrari, Laurens Vanthoor in the No. 912 Porsche, Alexander Sims in the No. 26 BMW and Oliver Gavin in the No. 4 Corvette.
In GTD, both Michael Shank Racing Acuras pitted, with Luca Stolz sliding into the No. 33 Mercedes and Gunnar Jeannette in the No. 63 Ferrari behind class leader Madison Snow in the No. 48 Lamborghini prior to the caution. Sellers took over in the No. 48 Lamborghini during the caution, followed by Christopher Mies ion the No. 29 Audi and Stolz in the No. 33 Mercedes-AMG.
Green-flag racing resumed at the 10-hour, 35-minute mark, with Derani quickly passing Nasr to regain the lead.
The 11th caution waved only three laps later for the stopped No. 66 Ford GT of Dirk Mueller.
Racing resumed at the 10-hour, 46-minute mark. Derani pulled away in the lead while Tincknell passed van der Zande for third while getting side-by-side with Nasr in an unsuccessful bid for second.
Hard racing for every position! pic.twitter.com/lienHkpXtG
— IMSA (@IMSA) March 18, 2018
As the event entered the final hour, Derani led Nasr by 3.392s, followed by Tincknell, 3.964s and van der Zande, 4.473s behind.
GTLM saw Tandy ahead of Sims by .491s, with Pier Guidi third, 8.159s back.
In GTD, Sellers led Stolz by .493s and Mies by 1.124s.