Yes there are substantial similarities between the origins and development of the silk road and the trans-saharan trade. Both the routes originated for the purpose of trading. Climatewise both the roputes had to pass through the harsh desert conditions. The silk route passed through the tarim basin and it was similar to a desert. The trans-saharan trade route passed through the harsh Sahara desert. Timbaktu was a famous outpost in the tras-saharan trade route while the silk route had the famous Samarkand as the outpost.