Complex sentence: Kristian and Julia run into a massive traffic jam clogging the upward road; realizing they are nowhere near high enough, Kristian gets out of his car with Julia and begins running up the road on foot, yelling for everyone else to do likewise.
Split into simpler sentences: Kristian and Julia run into a massive traffic jam clogging the upward road. Realizing they are nowhere near enough height, Kristian gets out of his car with Julia and begins running up the road on foot, yelling for everyone else to do likewise.