Whenever I am in a new city, I try to learn about their transport system. This includes finding out if they have some conveniences with respect to public transport like a transit card that you can use for various modes of public transport. Examples of these are cards in Singapore, Hong Kong and Japan that you can just reload (top up) and swipe or tap at terminals found in most if not all public transport. In Japan, you can even use their cards to purchase items at convenience stores or vending machines.
San Diego has what it calls the Compass Card, which you can use for the trolley and bus services. You can purchase a card from the Transit Store or at any of the machines located at the trolley stations. The Compass Card can be used to load day passes (instead of purchasing paper passes).
Compass card vending and reloading machine – you can also purchase special tickets here like the 1-day Pass that basically allows you to have unlimited use of the trolley and buses within the day of purchase.
Compass card front shows also the private sponsor/partner of the MTS – Albertsons
At the back of the card are information on the use, care and expiration of the card.
Timetable and route information for the San Diego trolley