Complex sentence: Newer innovations emerged in the early 20th century with side friction and underfriction technologies to allow for greater speeds and sharper turns, and by the mid-to-late 20th century, these elements intensified with the introduction of steel roller coaster designs and the ability to invert riders.
Split into simpler sentences: Newer innovations emerged in the early 20th century with side friction and underfriction technologies to allow for greater speeds and sharper turns. By the mid-to-late 20th century, these elements intensified with the introduction of steel roller coaster designs and the ability for them to invert riders.