Driving to Endanger is one of the most general traffic violations. Maine law describes a driving to endanger, also known as reckless driving charge as the following:
A person commits a Class E crime if, with criminal negligence as defined in Title 17-A, that person drives a motor vehicle in any place in a manner that endangers the property of another or a person, including the operator or passenger in the motor vehicle being driven.
This definition can be applied to many different situations. Just looking at the Portland Press Herald's weekly state and local dispatch report shows the unpredictability of this charge.
For example, a man in Windham lead police on a high speed chase after the car he was driving was reported stolen by its onboard security system. The chase finally ended in police deploying a spike mat to stop him. The man was charged with multiple offenses driving under the influence, theft, driving without a license, eluding police, criminal speed and driving to endanger. This charge makes sense because he was driving at 70 to 80 mph.
Now, consider another case in York County where a motorcyclist also led police on a high speed chase. Police tried to stop the motorcyclist for speeding over 30 mph over the limit. Instead of stopping, the driver accelerated. He was driving so dangerously that police finally gave up the high speed chase and issued a warrant for his arrest (based on his license plate info). He later turned himself in and was charged with charged with eluding an officer and passing a police roadblock, but not driving to endanger.
Looking at these two cases, there appears to be no clear reason why one offender was charged with reckless driving and the other was not. Both eluded police and both drove at speeds of 70 to 80 mph. It seems that driving to endanger charge is one of those charges that can be used if prosecution feels the penalties for the other charges might not be enough punishment for your crimes.