SAN FRANCISCO (CBS SF) — Muni’s new pilot program charging Google and other tech corporate shuttles to share a network of designated bus stops in San Francisco prompted protesters to block buses leaving from the Mission District Friday morning.

Two tech buses were stopped by a crowd of protesters who flooded 24th and Valencia streets.

The program launched Friday as part of an 18-month transportation experiment that has Silicon Valley corporations paying for the privilege to use Muni stops.

The pilot has been six years in the making. Eleven permitted shuttles can now pick up commuters at 99 designated Muni stops in San Francisco.

Corporations pay the city $3.55 per stop, but many protesters have held several other demonstrations against the shuttles over the past year. They say the shuttles are a symbol of the city’s rising cost of living and changing demographics.

“To calculate the real number has to be what effect does this have on the community around these stops and how do we pay for that,” said Sarah Sherbum-Zimmer, a Google bus protest organizer.

City leaders call these buses an extension of mass transit and estimate there are 35,000 shuttle bus boardings per day.

“Thousands of San Franciscans rely on these shuttles to get to work and to earn a livelihood everyday, and we need stop politicizing their ability to do that,” San Francisco Supervisor Scott Wiener said.

The course of the pilot program is expected to raise $3.5 million and all of that money has to go back into the shuttle bus program. Anything else would illegal because if they pass a tax for profit, voters would need approve it first.

The city has been training parking officers in preparation for Friday’s launch. There are also 10 specialized officers all over the city to monitor the morning and evening commutes.