Guanajuato → San Luis Potosí · Autopista 45D Salamanca-Querétaro
What does it actually cost to drive from Salamanca, Guanajuato, to San Luis Potosí, San Luis Potosí? The hard numbers: 222 km (138 miles) of pavement primarily along Autopista 45D Salamanca-Querétaro, 2h 28m behind the wheel, and roughly MXN 447.70 in fuel alone — that is 18.5 liters (4.9 gallons) of gasolina Magna at a 24.20 MXN/liter benchmark. Anyone leaving Salamanca, the sede de la refinería Ing. Antonio M. Amor de Pemex, typically carries samples, signed proposals, or service equipment to deliver in San Luis Potosí, the capital potosina y nodo logístico que conecta el Bajío con el norte del país, and aims to be home the same evening. It is worth confirming whether the haul fits inside your daily hours-of-service window or whether an overnight at a midpoint hotel makes more sense. Applying the tarifa promedio de mercado mileage rate of MXN 6.50/km (MXN 10.46/mile), the gross outbound reimbursement settles at MXN 1443.00. Attach the visit purpose, client name, and plate number to the Clara receipt so the journal entry lands directly in the business-travel expense account. For the US professional driving the 222 km (138 mi) between Salamanca and San Luis Potosí, reimbursement of MXN 1443.00 stays non-taxable to the employee when the employer follows an accountable plan under Treas. Reg. §1.62-2 and reimburses at or below the IRS standard mileage rate. US employers generally reimburse at the IRS standard mileage rate so the payment stays non-taxable to the employee under Pub. 463. Keep the IRS-compliant expense report (Form 1040 Schedule C, line 9) alongside the fuel receipt from any EIA-tracked retail station network pump used along the leg; Internal Revenue Service (IRS) examiners pull contemporaneous mileage logs first when auditing Schedule C unreimbursed business expenses, and the Salamanca→San Luis Potosí corridor must show date, business purpose, and odometer readings.