Why was the Silk Road treacherous?
4000 miles between two continents and numerous different cultures, deep deserts and high, snow peaked mountain ridges - if that is not enough add bands of robbers along the way, tribute hungry local rulers looking for treasure ladden caravanes - you need more?
Add political unstable regions, nomadic fighters and military expansions all along the way between Changan and Byzanz (Constantinople). Can't be more treacherous!