Widening a Road Surface

Add a Traveled Way/Shoulder Lane

You can widen traffic lanes on straight sections of multi-lane roads to reduce sideswipe crashes, or on bends for larger vehicles by giving drivers more room to get around the bend without crossing into the opposing lane. You can add a traffic lane, a median or an island area on straight sections of multi-lane roads to reduce sideswipe crashes.

You can add a new lane locally by modifying road specifications on a specific point. You can manage the specification of lanes, medians and shoulders along the horizontal alignment. Lanes and medians can be distributed on each side of a planar or crowned surface. Traveled way right and left widths can be driven by dedicated length laws.

From the Road and Railway section of the action bar, click Horizontal Alignment .
Choose the Road or Highway configuration.
Each configuration corresponds to a road/highway profile that can be defined with Data Setup. See Alignment Design Customization.

After selecting an existing profile (road or highway), you can modify attributes:
- Profile Specifications:
  To create a customized road, you can directly edit some attributes, and click OK to validate. The customization is only local to the edited 3D Shape, it does not impact Data Setup.
  Road specifications can also be modified from a given station using Alignment point dialog box.
- Traveled way lane distribution: when no there is no lane definition, only this button is available. To define it, select an existing lane type or create a new one by clicking .
- Shoulder lane distribution: To define it, select an existing lane type or create a new one by clicking .
- Rules: correspond to the selected profiles, managed in Data Setup. You cannot edit them.
Road specifications and traveled way lane/shoulder lane distribution can also be modified from a given station using the Alignment point dialog box. In the Horizontal Alignment Initialization and the Alignment Point dialog boxes, customization is only local to the edited 3D Shape, it does not impact the Data Setup.
To edit profiles specifications, click to switch to edition mode. Then modify attributes, for example speed, and click OK to validate.
To add a new lane, click in the Traveled way lane distribution section. In the Lane Chooser dialog box, you can do the following:
- Select a lane type: an existing lane or create a new one.
- Change Lane specifications: when the selected lane has a traveling direction set to One way, a right/left arrow is displayed next to the Remove button . To inverse the traveling direction, click the arrow.
- Edit Vehicle parameters: the selection of a vehicle type automatically increases the lane width if the vehicle does not fit the lane.
Click OK to validate the profile specifications.

Widen Shoulder Lanes and bends

You can add the additional width of the traveled way that is required on a curved section. The administrator can edit an xml file, shared by the project team in the Data Setup to manage traveled way widening by laws (automatically computed).

Lanes, medians and shoulders, along the horizontal alignment, can be distributed on each side of a planar or crowned surface. As the swept path width (the amount of roadway width a truck covers in negotiating a turn and is equal to the amount of offtracking plus the width of the tractor unit), the front overhang width (the circular arc formed by the turning path of the front side of a vehicle) and the lateral clearance (it provides clearance between edge of the traveled way and nearest wheel path and for the body clearance between vehicles passing or meeting) are considered, curves can be widened automatically in the Horizontal Curve dialog box. For more information, see Alignment Design Customization.

Planar shoulders can be created on each side of the traveled way. Their slopes are managed by dedicated angular laws (automatically computed). In tangents, a fixed angle is applied. When the traveled way is superelevated, the angle is rectified so that the roll-over does not exceed a targeted value as the slope between the traveled way and the shoulder must not be too important. Their widths is either fixed, with possibly a different value for each side of the traveled way, or managed by dedicated length laws.

From the Road and Railway section of the action bar, click Horizontal Alignment and choose an existing configuration (road or highway) in the Horizontal Alignment Initialization dialog box.

Each configuration corresponds to a road/highway profile that can be defined with Data Setup. See Alignment Design Customization.
To custom the road, modify the following attributes if necessary: Profile Specifications, Traveled way lane distribution, Shoulder lane distribution, Rules.

The customization is only local to the edited 3D Shape, it does not impact the Data Setup.

You can design the shoulders or turnouts of the road (not only the crown part of the road) for emergency use in the Horizontal Alignment command and, manage superelevation in slopes between the traffic lane and the shoulder in the Road Surface dialog box. After shoulder design, you can manage shoulder superelevation in bends to avoid high slope between the traveled way and the shoulder.
To manage superelevation on shoulders in bends, do one of the following:
- Fix their width with possibly a different value for each side of the traveled way
- Manage their width by dedicated length laws that can be automatically computed as it is done for the traveled way.
Shoulders can be created on each side of the traveled way. Their slopes are managed by dedicated angular laws that can be automatically computed: In tangents a fixed angle is applied. When the traveled way is superelevated, the angle is rectified to ensure the Roll-Over (not to have a large slope between the traveled way and the shoulder) does not exceed a targeted value.

Shoulders (sharp grade break between the traveled way and the shoulder) can be planar. Roll-over is also considered as a cross section element (algebraic difference between the traveled way and the shoulder; maximum value: from 6 to 7%).
To widen a curve automatically, set the Curve Widening Auto parameter as true in the Horizontal Curve dialog box.
To widen a curve manually, set the Curve Widening Auto parameter as false and edit the Curve Widening value.
When the Ratio on Inner Edge Auto is set as true, the laws in RoadAlignmentDesign.xml are automatically computed to consider the curve widening which depends on the swept path of a design vehicles and possibly lanes distribution. With these laws, the Ratio on Inner Edge value is equal to 50% for example, it means that the width on each side of the curve is the same.
To manage widening independently on each side of the bends (or crowned surfaces), set Ratio on Inner Edge Auto as false and enter 100% for the Ratio on Inner Edge.
In this example, widening only occurs on the inner side of the bend.