What are the rules for bringing pets on TriMet?

Pets are welcome on TriMet under certain guidelines. Small pets, such as cats and dogs, are allowed to travel on TriMet buses and trains as long as they are in enclosed carriers with ventilation. The carrier must be small enough to fit on the owner's lap or be placed under the seat. Service animals, defined as dogs or miniature horses trained to assist individuals with disabilities, are also permitted. These animals do not need to be confined but should remain well-behaved and in control. Pets are not allowed on seats or in the aisle, and owners are responsible for any damages caused by their pets. TriMet reserves the right to refuse service to any pet that poses a threat or disturbance to other passengers.