In smm2, slopes were introduced. There are steep and gentle ones, and the twitter user @relaxmas1 did some research on them to figure out the quickest way to bypass them. Down below I linked the tweet of his results. https://twitter.com/relaxmas1/status/1145417713575059456?s=21

Edit: recently, he added some information on jumping on slopes as well: https://twitter.com/relaxmas1/status/1145530671282049026?s=21