While the Dumb & Dumber film was not actually filmed in Aspen, Colorado the directors do shoot for some accuracy. The hotel labeled "The Danbery" used in the movie was actually the Stanley Hotel located in Estes Park Colorado which is 200 miles away and 4 hours and 30 minutes by car if driving down to Aspen. The police cars used in Aspen, Colorado at the time were Saabs like the one pictured below:
After the villains Nicholas Andre and JP Shay get arrested at the end of Dumb & Dumber they are hauled away in a Saab Police car even though Estes Park, Colorado did not use Saab Police cars while Vail & Aspen Colorado did as you can verify for yourself in the clip below.