I am not familar with the laws in Iowa but does DOT stand for Department of Transportation have a legal authority to pull anyone over? Maybe they are the state police in Iowa.
UPDATE:
The officer in question is now the subject, along with IDOT, of a civil suit brought by a seventy one year old semi driver whose story is that four years ago this officer repeatedly pistol whipped him. David Howard of SD spent that night in jail but the next morning in court a Henry County ( IA) judge took one look at him and dismissed the charge of insutling a law enforcement officer....
Subsequent discussions between Mr Howard and IDOT went nowhere and four years agao the Henry County Attorney refused to take the officer and IDOT to court.
Now ---four years later--- Mr. Howard has again filed suit against Officer Wiegand and IDOT....
The Assistant Iowa Attorney General immediately came forward with a motion to dismiss, which appears to be still under review by a Henry County judge.
Even letters of support would be helful for Mr. Howard. It is important that this go to court so that ALL SIDES are considered and the truth will be heard, and Mr. Howard is to be commended for his tenacity.
I always refuse LEOs when they ask to search my car. And some of them just about have a heart attack. And they threaten a lot of things, but they do back off. And it always seems they say the samething, "If you have nothing to hide you would let me search." I always tell them the samething, "I have nothng to hide and no you still can not search."