For the previous reviewer: fastest means the quickest amount of time based on current trafffic conditions. Shortest is the shortest mileage, which is helpful if you’re renting a vehicle and are getting charged by the mile.
INRIXTraffic’s routes are reliable, and the time estimates are based on current traffic flow according to past and current drivers on the same route. In two years of use, there have been some times that it hasn’t shown a new accident or construction (which depend on user input) and the time estimates are generally quicker than I drive since many people go 15-20 mph over the speed limit in my area, so don’t count on catching a few green lights and arriving earlier than predicted.
I do wish that it had a view that lists the turns, instead of only the map mode, but the graphica are clean and overall I’m happy with INRIXTraffic.