If you want to show that a feature (in this case a park) abutts a highway, then please map the highway area and have the feature and area share common nodes. That makes it easier for others to edit highways because the highways aren't hidden by other features, and it doesn't result in the oversizing of features. In this case the park is oversized because its boundary envelopes half the width of the highway. 

Generally areas don't need to share common nodes with highways, the exceptions are for barriers.