Task: Question Answering
Input (English): Passage: After the Southwest became part of the U.S., explorers continued to look for good east–west routes along the 35th parallel. In 1853, a crew led by U.S. Army Lieutenant Amiel Whipple surveyed along a sandy wash in the northern part of the Petrified Forest. So impressed was Whipple by the petrified wood along the banks of the arroyo that he named it Lithodendron Creek (Stone Tree Creek). Geologist Jules Marcou, a member of the Whipple expedition, observed that the petrified trees were from the Triassic.A slightly later route along the parallel was a wagon road, built between 1857 and 1860, that involved experimental use of camels as transport. In the late 19th century, settlers and private stagecoach companies followed similar east–west routes. Homesteaders who stayed in the area developed cattle ranches on the grasslands, and cattle grazed in the Petrified Forest until the mid-20th century.Also close to the 35th parallel was the Atlantic and Pacific Railroad. Its opening in the early 1880s led to the founding of towns like Holbrook and Adamana. Visitors could stop at the Adamana train station, book a hotel room, and take a tour of what was then called the Chalcedony Forest. Over the years, the line changed hands, becoming the Atchison, Topeka and Santa Fe Railway, and then the BNSF. More than 60 BNSF trains, mostly carrying freight, pass through the park every day. U.S. Route 66, a former transcontinental auto highway developed in 1926 from part of the National Old Trails Road, ran parallel to the railroad tracks until it was decommissioned in 1985. The park has preserved within its boundaries a small grassy section of the road. Interstate 40, which crosses the park, replaced the older highway. 
Question: What road did Interstate 40 replace?
Output (English): U.S. Route 66.