Here’s the summer road-trip scenario cooling mats exist for: it’s 95°F, the AC died somewhere outside Barstow, and your 80-lb Lab is panting like a freight train in the back seat. A cooling mat buys you real relief. No cooling mat — or the wrong one, sized for a Chihuahua — buys you a miserable dog and a stressful drive. The honest note most roundups skip: cooling mats are not air conditioners. Gel mats absorb body heat and need recharge breaks; water-filled beds are heavy; and “self-cooling” still depends on airflow and ambient temperature. A mat that feels icy in…