(WCMH) – The Iowa Department of Transportation took to social media this week to clarify the meaning of deer crossing signs on the highway.

Iowa DOT says they regularly have people asking why they don’t place deer crossing signs where it is safer for deer to cross the road.

Iowa DOT’s response:

Deer can’t read signs. Drivers can. This sign isn’t intended to tell deer where to cross, it’s for drivers to be alert that deer have been in this area in the past.

Iowa DOT has reported more than 3,300 crashes involving animals so far this year. One person has been killed and 156 people injured as a result of the crashes.

A clip of a woman calling into a radio show to ask as similar question went viral on YouTube in 2012.