By default, junctions are created with as standard "T-Junction", as per this example:
You can easily add a lane or taper to the entry and exit sides of the junction.
To alter the style of a junction to a lane or taper, use the Edit Junction Dimensions tool on the junction tools toolbar.
Once in this tool, right click over the left or right side of the junction to see the following menu:
Select either Change to Taper or Change to Lane to change the junction style.
NOTE: It is always possible to change a taper to a lane, lane to taper or revert a lane or taper back to a normal fillet by right clicking over the appropriate side of the junction whilst in the Edit Junction Dimensions tool.
To specify or alter the lane/taper length, width or fillet radius, select the Edit Junction Dimension tool, and select the relevant dimension item on the plan-view with the mouse (left click). You will then see the design stretching as you move the mouse. Left-click the mouse again to confirm the new length, width or radius.
You can specify exact lane/taper length, width, radius or crossfall values by right-clicking the mouse whilst in the Edit Junction Dimensions tool: From the menu, select either the Enter Lane/Taper Length, Enter Lane/Taper Width, Enter Radius or Edit Crossfall option. This will ask you to enter a value, then update the junction instantly.
The example below shows a taper on the left and a lane on the right with their appropriate dimension annotations which can all be edited the the ways described above.