When we dynamically draw the linework for any string/road, we employ a 'quick draw' technique so that we can update the linework as you make changes. The objects, when you select them, are blocks and not lines/polylines.

One drawback of this is the representation of the linework at the time of plotting - the objects won't respond the same as others to the colour table.

Before you send to printer, you should use the command Cad Output in the Plan Production panel - this will output 2D and/or 3D polylines for the linework and this will represent exactly as expected when sent to the plotter.