Besides Santa Margarita, San Luis Obispo is one of my favorite towns on the Central Coast. It is interesting that SLO has Southern Pacific Railroad and a major U.S. Highway (101) running through it with every possible type of commodity, truck and passenger vehicle. In addition, two other highways merge in SLO (Highway 226 and Highway 1). With all this, most students at Cal Poly as well as a large majority of residents ride bicycles everywhere without incident.
Santa Margarita has Southern Pacific Railroad running through it with myriad commodities, as well as some traffic that includes some trucks hauling quarry material.
I do not see any reason why the county supervisors would not vote in favor of Las Pilitas quarry as it has little effect on Santa Margarita. I would be more concerned about the Southern Pacific Railroad that runs through town. I just wanted to put the traffic issue into perspective.