Two pregnant women were among six passengers on a Greyhound bus who suffered minor injuries when the driver lost control and slammed into a parked truck about a block from his destination. One of the pregnant passengers suffered labor pains and was admitted to Mission Hospital Regional Medical Center. The pains subsided, but she remained in the hospital for observation. The other five injured passengers, including the second pregnant woman, were treated for bumps and bruises. While the accident remains under investigation, police said the driver, Benjamin Franklin Singleton, 46, of National City was not under the influence of alcohol or drugs. He was neither cited nor arrested.