Use dim values in VB.NET

The indentation of the new declaration compared with the old, and the word "usin" implies it might be within a method rather than outside. If so, then the variable is only available within the method - it goes out of scope at the end of the method and cannot be accessed in any other method.

Dim parallelLines3 As New List(Of PointLatLng)
Public Sub MyMethod()
    Dim parallelLines4 As New List(Of PointLatLng)
    ... parallelLines3 and parallelLines4 available here
End Sub
Public Sub MyOther Method()
    ... parallelLines3 available here
    ... parallelLines4 not available here
End Sub

In addition, if you are declaring it as part of a Using block, then it is only available within the block - once it ends, it can't be accessed again.

Public Sub MyOther Method()
    Using parallelLines4 As New List(Of PointLatLng)
        ... parallelLines4 available here
    End Using
    ... parallelLines4 not available here
End Sub