I started a new game in 2.1.8 and used this mod to benchmark possible intersections for my new save.
Turned out, your Simple design can be easily adjusted for U-Turns :)

Unfortunately the mod crashed just after displaying the results, the following notice popped up every time the results were shown:
"The scenario level caused a non-recoverable error.
Please report this error to the scenario author.

Error while running event level::on_nth_tick(60)
Testbenchcontrols/gui.lua:2365: attempt to concatenate local 'display_name'
(a table value)
stack traceback:
Testbenchcontrols/gui.lua:2365: in function 'build_table_tab'
Testbenchcontrols/gui.lua:2457: in function 'Create_ Result_ Window'
Testbenchcontrols/scenario_control.lua:2578: in function 'calculate_test_score'
Testbenchcontrols/scenario_control.lua:2477: in function 'handleTestCompletion'
Testbenchcontrols/scenario_control.lua:2423: in function 'handle_testbench'
Testbenchcontrols/scenario_control.lua:586: in function
<Testbenchcontrols/scenario_control.lua:571>

Thanks, I can't do anything with it in two weeks. If you take a blueprint of the intersection and place it back down with the BP button should workaround that for now.