DES MOINES, Iowa (AP) — State transportation officials are warning motorists that as Iowa’s corn crop grows taller, they need to be extra cautious at intersections and railroad crossings. The Iowa Department of Transportation says the state had 33 crashes in 2012 that were blamed on obstructed views due to trees or crops. Those crashes left one person dead and at least 40 people injured.

Although most people who have lived for any stretch in Iowa are accustomed to crops occasionally hindering views, state safety engineer Jeremey Vortherms says people still underestimate the danger. At uncontrolled intersections, Vortherms says drivers should act as if a stop or yield sign were posted.