Being an international company just only having travel calculations done only on roads isn't sufficient enough. There are situations that even in countries based on locations of engineers / customers travel can happen on very long distances. So it would be great to be able in scale the AVG travel time based on the distance assuming that on longer distances either train or plane will be used.
For sure it will never fit completely but at least it will become more realistic and usable when you use Recommend Resources and Propose schedule.
0 - 50 km AVG travel speed will be 30 km (most likely traveling in the city)
50 - 300 km AVG travel speed will be 60 km (travelling using highways)
300 - 600 km AVG travel speed will be 150 km (using fast train)
600 - 2500 km ACG travel speed will be 300 km (using plane)
These AVG needs to be scalable at least per country, and flexible due to the country needs
What is the underlying problem do you intend to solve with this idea?
Having engineers more realistic reserved being on travel and therefor not available
How is the problem being addressed today, if at all?
Not sufficient enough and therefor with a lot of manual work