San Luis Potosí → Guanajuato · Autopista 57D México-San Luis Potosí
Returning from San Luis Potosí, San Luis Potosí, back to León, Guanajuato, the itinerary retraces the same 168 km (104 miles) of the outbound segment, predominantly via Autopista 57D México-San Luis Potosí, adding another 1h 52m to the corporate odometer. Unlike the outbound leg, the homeward journey is usually executed at the close of the business day, when heavy truck traffic, accumulated fatigue, and dropping daylight all demand sharper focus. Anyone hoping to ease the arrival back into León, the capital del calzado y mayor ciudad de Guanajuato, may consider an overnight stop in a midpoint town and splitting the haul into two shorter stints. Fuel expense holds steady near MXN 338.80, totalling roughly 28.0 liters for the entire trip when added to the outbound segment. The return reimbursement reaches MXN 1092.00, doubling the aggregate payout for the full journey. Log each leg separately in the Clara receipt, with distinct timestamps, so the paperwork accurately mirrors the vehicle's actual movement. For the US professional driving the 168 km (104 mi) between San Luis Potosí and León, reimbursement of MXN 1092.00 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 San Luis Potosí→León corridor must show date, business purpose, and odometer readings.