The "sap" may be from insects, excreted by aphids or, in some cases, scale insects. You may be able to dislodge and reduce offending aphids in the tree by blasting overhanging branches with a forceful stream of water from a hose. If the source of honeydew is scale insects this won't help much, however. Spraying with insecticide is rarely needed to protect health of the tree.
The best solution is don't park under the tree again. To remove pine pitch, tree sap or honeydew from a car, wash and dry the car, apply a wax and grease-removing product, and rewax. Or, you can try dissolving sap with alcohol.
The best solution is don't park under the tree again. To remove pine pitch, tree sap or honeydew from a car, wash and dry the car, apply a wax and grease-removing product, and rewax. Or, you can try dissolving sap with alcohol.