APM: 0 Location: SR 188 and Thing Rd, Tecate, San Diego Cty SR 188 begins as we enter America. APM: 0 Location: SR 188 and Thing Rd, San Diego Cty Welcome to California! APM: 0 Location: SR 188 and Humphries Rd, San Diego Cty Trucks are prohibited on SR 188, which probably would have been a good thing … Continue reading California State Route 188, MX-3/BC Int’l Boundary to SR 94