If you’ve decided to drive to Oaxaca, you have your choice of four general routes. At safe highway speeds, from the Mexican border these routes require as many as five days or as few as two days, depending on your route.
The longest but most scenic route is the Pacific route, which starts out as Mexican National Highway 15 from the border at Nogales, Sonora, an hour’s drive south of Tucson, Arizona. Soon you join Highway 15D cuota autopista (toll expressway)—or continue along old libre (free) Highway 15—proceeding southward smoothly, over cactus-studded plains mountains that give way to irrigated farms and groves and palmy tropical coastal plain by the time you arrive in Mazatlán. Follow the periféricos (peripheral bypasses) that conduct traffic past the congested downtowns of Hermosillo, Guaymas, Culiacán, and Mazatlán. Between these centers, you can speed along via the cuota Highway 15D expressway virtually the entire way. If you prefer not to pay the high tolls (around $60 total for a passenger car, much more for multiple-wheeled RVs) you should stick to the old libre Highway 15. Hazards, bumps, and slow going might force you to reconsider, however.
At Tepic, the Pacific route leaves Highway 15–15D and continues south via Highway 200, winding past tobacco farms and mango orchards, through lush forest, climbing vine–hung canyons, crossing a score of rivers, past a host of palm-tufted beaches, and passing the renowned vacation lands of Puerto Vallarta, Manzanillo, Ixtapa-Zihuatanejo, and Acapulco. Finally, several days after you crossed the border, you arrive at the heart of the tropical Oaxaca coast at Puerto Escondido  or Puerto Ángel .
A speedier variation on the Pacific route is the Pacific–Mexico City route, which starts out as the Pacific route but departs from the Pacific coast, eastward, at Tepic, continuing along Highway 15 or 15D past Guadalajara, via Toluca to Mexico City.
Across town, at the Los Reyes southeast-side suburb, pick up the Puebla–Veracruz expressway Highway 150D, where you continue about an hour past Puebla to a fork. Follow the south fork expressway, via Tehuacán and Nochixtlán, to Oaxaca City . This nearly all-expressway route minimizes the road time from the western U.S. border to three very long, or, to be safe, four days to Oaxaca. Note: Be sure to arrive in Mexico City on a day of the week when driving restrictions (determined by the last digit of your license plate; see the sidebar Mexico City Driving Restrictions) do not apply to your car.
If, however, you’re driving to Oaxaca from the central United States, go via the central route, crossing the border at El Paso to Ciudad Juárez, Chihuahua. There, National Highway 45, preferably via the cuota multilane expressway (or, if not, the old libre two-lane highway), leads you southward past high, dry plains and the cities of Chihuahua and Jiménez (use periféricos to bypass downtowns). Continue via Highway 49 southwest, through Gómez Palacio and the silver colonial cities of Zacatecas to San Luis Potosí, where you connect with Highway 57 expressway, via Querétaro, to the northern outskirts of Mexico City.
At that point, best use the east-bound periférico expressway via Carpio and Tezcoco instead of trying to fight your way through downtown Mexico City. At Los Reyes on the southeast side of town, pick up Highway 150D, the expressway east to Puebla, where you continue southeast via the toll expressway to Oaxaca (as described two paragraphs above). To be safe, allow three daytime-only driving days for this route.
Folks heading to Oaxaca from the eastern and southeastern United States probably save the most time by crossing the border from McAllen, Texas, to Reynosa and taking the eastern route to Oaxaca. Continue south, via Highway 97 then Highway 101, to Ciudad Victoria, bypassing the downtown by the perférico. Then connect with Highway 80 to Tampico. There, again bypass the downtown and pick up Highway 105 south headed for Tempoal de Sánchez. After a long, winding, mountain climb via Huejutla de Reyes, you reach Pachuca and continue southward via expressway Highway 85 to Mexico City. At Carpio in the northern suburb, take the east bypass expressway, via Tepexpan and Tezcoco, continuing to east-bound expressway 150D for Puebla. There, you continue southeast to Oaxaca City  (as described three paragraphs above). If you start off at dawn each morning, you could probably get to Oaxaca safely in two driving days, under optimal conditions. Best do it in three leisurely days, including two overnights.