Roberto Villanueva glances in the rearview mirror of his taxi as he turns onto a side street heading toward Macuiltépetl, an ecological reserve on a mountain in the center of Xalapa. He’s been driving a cab here in the state capital of Veracruz, Mexico, for 35 years, and has most routes through the city committed to memory. “Almost muscle memory,” he says. That’s no small feat in Xalapa, a sprawling, hilly city of 750,000. Xalapa’s streets evolved centuries before automobiles and are full of abrupt turns, unpredictable name changes, and…