Trips on these non-narrated buses are informal.
Narrated tour buses are tan-colored and will not stop to pick up hikers. Transit buses are painted green, to help you identify them from far away.
Re-boarding is on a seat-available basis, so you may wait anywhere from five minutes to an hour or more for a bus with ample seating. If you get off your initial bus, you can flag down any other non-narrated bus going in your desired direction-i.e., farther into the park, or back towards the entrance. Thus, this is the type of bus you want to take if you're interested in a day hike, or just want to experience the park on your own terms rather than as part of a tour group. Unlike tour buses, however, you're not limited to staying on the bus in which you originally started. They make regular restroom stops and wildlife-viewing stops, just like the narrated tour buses. All non-narrated buses, called transit buses, are designed to move people around within the park.