While HDM-4 is powerful, it is not a "black box" to be trusted blindly.
Comparison with alternatives (high-level) hdm-4 software
Applying HDM-4 to model axle-load control on the Douala-N’Djamena corridor generated over €500 million in savings in road maintenance and user costs between 2000 and 2015. While HDM-4 is powerful, it is not a