Short breaks, heartbreak

Round island#7, 123 km. The roadies are out in full force at Changi. Some of them draft behind a motorised bicycle. The two roadies I draft behind have really long limbs. The lead cyclist seems to be languidly moving his legs, while the second rider seems to be working his legs and his cranky clanking crank overtime. They u-turn and I'm alone again. While this is my seventh round island, there are several firsts. It's my first in daylight and with contact lenses (using rewetting eyedrops at the start helps). It's my first in 2004, with ant-infested snacks ... and with 1.25" slicks. But I'm still taking almost six hours to complete the ride, with four breaks (actual cycling time: 5 hr 4 min). My breaks are barely 30 minutes in total, so the rest of the time must have been waiting at traffic lights. Why am I so slow? Average speed is 24.2 km/h, max 41.9 km/h. Should I blame the traffic, the heat, or simply old age? I'm so tired, my mind drifts and I almost run a red light. Looks like the guy floating beyond the barbed wire at Kranji, collecting stuff in a box, had more fun.