A distinguished task force of judges, lawyers, and family court professionals did a great job of defining shared parenting to include parallel parenting.
“even in circumstances where shared parenting may appear difficult, depending on the child’s age, maturity, and other circumstances, parents still could have minimal communication and coordination and yet share the raising of their children in what is called “parallel parenting” (an arrangement in which parents agree to exchange important information about the child’s welfare, but otherwise permit each other to parent the child autonomously).”
Source: “CLOSING THE GAP: RESEARCH, POLICY, PRACTICE, AND SHARED PARENTING” by Marsha Kline Pruett and J. Herbie DiFonzo. (Family Court Review, Vol. 52, No 2, April 2014).