Glacier National Park's historic bright red touring buses, refurbished vintage White Motor Company vehicles, have carried passengers along Going-to-the-Sun Road for nearly 70 years, offering visitors a way to experience the park's scenery and wildlife without the distraction of driving. They hold the record for the longest continuous service of any fleet in the United States, and perhaps the world, but by 1999 they were still running on mostly 1930's technology, and safety concerns forced them out of service. Their absence was deeply felt because the buses had become closely linked to Glacier's history and spirit. Ford Motor Company then helped rehabilitate the fleet with modern engineering, preserving a cultural treasure while making the buses safer, cleaner, more fuel efficient, and more comfortable, and in June 2002 they returned to service for a new generation of travelers. The restoration included stretched Ford E-450 chassis built to the original wheel base, 5.4L V8 bi-fuel engines using LPG, aluminum honeycomb floors for greater strength, emissions 93% cleaner, lighter rear doors and body reinforcement, upgraded glass and lighting, upgraded instrument panels, and environmentally friendly paint. The buses grew out of Glacier's evolving transportation history, from Great Northern Railway hotels and chalets linked by horseback and stage coach travel to full-time motorized transportation beginning in the 1914 season, and their rehabilitation required a team of more than 200 experts working for nearly three years.