Do I need an attorney for my auto accident?

It is probably better to have an attorney. An attorney can often help bargain to a reduction in what you are charged with; to a reduction in any criminal fines or penalties; and also reduce the points that might accrue to your license. You should get an attorney before your arraignment, so he/she can go to court with you.

Although I do not practice law in the State of Minnesota, here are my initial impressions.  I generally agree with my colleague's advice.  However, another aspect that you will need to address is whether or not you have car insurance, because there is very likely going to be a civil suit arising out of this incident.  If you have insurance, your carrier should pay for an attorney to represent you in any civil suit that arises.  Even though you state that there were "no injuries", do not be surprised if the other party suddenly develops some.  Moreover, if you are found guilty of the traffic violation, that can be used against you in the civil context.  Thus, if you have insurance, you need to notify them immediately.  Good luck.