Harley Wagner, Dugger's attorney, said Humphrey's decision was based on evidence that showed Dugger did not cause Bish's death.
"I think it's clear from the finding of no probable cause by the court that there exists significant doubt as to whether Ms. Dugger caused this accident," said Wagner, adding Bish should not have lingered in the middle of the road.
Dugger's blood alcohol content at the time of the wreck was .192 - more than twice the legal limit of .08. Dugger told police she had a glass of wine, according to records.
According to court records, when West Virginia State Police Trooper C.A. Ellwanger arrived at the scene, he smelled the odor of alcohol emitting from her.
A man riding in the car with Dugger at the time of the accident said he did not see anyone in the road before the accident, according to records. The man, identified as Jeremy Kelly, 24, had also acknowledged he had been drinking, records state.
Bish, who was wearing a black jacket and blue jeans, was dragged or carried more than 120 feet before the car stopped, according to records.
Berkeley County Assistant Prosecutor Josh Henline said he was disappointed by the decision.
"No probable cause is the lowest burden that the state must meet," said Henline, adding Humphreys' decision served to "invalidate" Bish's life.
"It's astounding to me that his life was invalidated in such a way," Henline said.
Henline said Bish had no legal duty to move out of the road.
"The duty is for drivers to use due care," Henline said.
A conviction on the charge carries a sentence of one to 10 years in prison.