Printable View
There's nothing wrong with the I-80 option, but it doesn't get a lot of talk because its basically the same route as going via I-70, except instead of traveling through one of the most scenic stretches of freeway in the world in UT and CO, you add 100 miles to your trip and travel through areas with more muted views.
There are two 'main' routes between Los Angeles and Chicago. They are a grand total of 1 mile different in length. The one we have been talking about is I-15 to I-40 at Barstow, then across through Flagstaff, Albuquerque and Amarillo to Oklahoma City. From there, you take I-44 up to St. Louis and finally I-55 into Chicago. The alternate route stays on I-15 up into Utah (but not nearly as far as Salt Lake City) switching to I-70 near the small town of Sulphurdale, UT and crossing the Rockies to Denver where you use I-76 to head northeast up to I-80 in western Nebraska. You would then take I-80 the rest of the way through Nebraska (Lincoln and Omaha), Iowa (Des Moines) to Chicago. As I say, those routes are really the same in distance. Which one any given computer based algorithm will recommend depends on the particular 'logic' that the program uses to determine the best route. All other things being equal, I would take the I-40 route if I would concerned about my car since the I-70/I-80 route requires that you gain almost an additional mile in elevation. But you are free to choose either route depending on your particular desires.
AZBuck
Google actually has the I-40 route being about 120 miles longer. In fact, they show going through SLC via I-80 is actually about 50 miles shorter than staying on I-40, but still 70 miles longer than I-70/I-76 through Denver.
But Buck's larger point is very much true. You're talking about 100 miles difference on a 2000 miles trip. Your actual travel time is going to be virtually the same no matter which way you go. Pick the route that looks most appealing to you - not a mindless computer program or triptik printout.