Complex sentence: Massa set the session's fastest time of 1:19.068 during its second part, but was unable to heat his tyres sufficiently--and achieve the maximum grip possible--due to traffic, and dropped to third overall in the final part of qualifying.
Split into simpler sentences: Massa set the session's fastest time of 1:19.068 during its second part, but was delayed by other cars, which prevented him from heating his tyres sufficiently to achieve the maximum grip possible. He dropped to third overall in the final part of qualifying.