Complex sentence: The crowd and the darkness convinced to delay the race start of half an hour, and to reduce the delay between cars to just one minute: the day was expected to be very hot, and the officials wanted to avoid the heat of the late morning.
Split into simpler sentences: The crowd and the darkness convinced the organisers to delay the race start by half an hour, and to reduce the delay between cars to just one minute. The day was expected to be very hot, and the officials wanted to avoid the heat of the late morning.