AC Transit took over the Key System in October 1960 and is the current provider of bus service in the East Bay. To view maps and schedules of their routes, visit actransit.org. Many of AC Transit's lines date back to the Key System days. These lines include the B, C, E, F, G, H, L, N, O, V, 7, 11, 12, 14, 18, 50, 51, 57, 72, and more.
A good story of AC Transit here
The AC Transit History website contains the full electronic collection of the Transit Times, AC Transit's monthly newsletter published form 1958 until 1989. It also has Then-and-Now images, scans of tokens and annual reports. Below is the cover of an annual report that AC Transit put out for fiscal year 1960/61. You can find the full annual report and other ones at AC Transit's history site.
The Fifty Four from Richard Koci Hernandez on Vimeo.