Driver of MH indicted in death of Police Officer

This is driver error or neglect. It is generally a criminal case. I worked in the court system a long time and saw many vehicle death cases. There is not really a defense here, as I see it, since it is the driver's obligation to maintain a safe distance and have control of the vehicle.
His driving record will likely determine the sentence. Also, if there are some witnesses who can describe his earlier driving prior to the crash, that will have an effect. Lots of at fault accidents and/or tickets will equal a harsher sentence. No priors will likely yield no jail sentence.