321.321  Entering through highways.
  The driver of a vehicle shall stop or yield as required by this chapter at the entrance to a through highway and shall yield the right-of-way to other vehicles which have entered the intersection from said through highway or which are approaching so closely on said through highway as to constitute a hazard, but said driver having so yielded may proceed cautiously and with due care enter said through highway.
[C27, §5079-b2, -b3; C31, 35, §5079-b2, -b3, -d2, -d3; C39, §5026.03; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §321.321]
For applicable scheduled fine, see §805.8A, subsection 7 
Additional penalties for violations causing serious injury or death, see §321.482A