Urban design - small intersections

urbn-dsn-sml-int-01.mp4 6:52

This video is review of the ETW setup corridor workflow covered in other training modules.

• We recommend creating this corridor in the alignment/profile drawing. This keeps the data flowing in a single direction and helps avoid circular references. The surface from this setup corridor can be data referenced in any corridor drawing where it is needed.
• Split the corridor into regions that only cover the intersection areas to save on drawing performance and processing time.
• Get one region setup up and then use the match parameters command from the corridor contextual menu to copy the targets and frequency settings to the remaining regions.
• Be sure to add a special frequency where the side road centerline alignment crosses the main road edge of travel way alignment.
• Once the intersection geometry is established later on, be sure to add a special frequency at the ends of the curb return radii. The regions can also be shortened at that time.

urbn-dsn-sml-int-02.mp4 6:34

This video is review of the side road profile workflow covered in other training modules but contains some slight adaptations to this scenario.

1. Open the proposed roadway corridor file
2. Data Shortcuts > Surfaces > Right-click on the ETW setup corridor surface > Create Reference
3. Create a profile view for the side road alignment
   1. Create an existing surface profile for the side road alignment
   2. Create an arbitrary proposed profile for the side road alignment.
      1. Snap two PVIs on the profile view that are outside each end of the alignment limits.
4. Add an intersection object where the side road centerline meets the main road centerline.
   1. Lock the side road proposed profile (priority 2) to the main road proposed profile (priority 1).
   2. Remember to uncheck the Create or specify offset alignments box before creating the intersection.
5. Create a surface profile for the main road edge of travel way alignment on the ETW setup corridor surface.
6. Repeat step 5 at the intersection of the main road edge of travel way and the side road centerline. The main road edge of travel way is priority 1.
7. Use the profile layout tools to delete the tangent adjacent the main road centerline location.

Tip: Locate the station in plan view where the side road profile should match into existing (construction limits). Use an AutoCAD point to mark this location. You may need to use the DDPTYPE or PDMODE command to change the point style and size so it is visible. The project the point to the side road profile view using the existing surface profile as elevation. The proposed profile can then snap to that location.

urbn-dsn-sml-int-03.mp4 6:34

For small intersections that match in quickly, there is no need for additional offset alignment based on the side road alignment. Instead, just create the curb return alignment and extend the tangents down the side road to the construction limits station. We recommend making the curb return alignments ‘Centerline" type because superelevation may be desired for these alignments during the curb ramp workflow. Miscellaneous type alignment cannot contain superelevation data.

One method for creating curb return alignments using alignment layout tools:

1. Use the AutoCAD offset command to offset the side road centerline alignment to the curb flange location (left and right).
2. Alignment > Alignment Creation Tools > Tan-Tan (No Curves)*
   1.   Digitize the three PI locations that define the curb return alignment.
      1. A point on the main road curb and gutter flange alignment beyond the expected curb return location.
      2. The intersection of the main road curb gutter flange alignment and the polyline representing the side road curb and gutter flange (created in step 1)
      3. A point on the side road curb and gutter flange polyline (created in step 1) beyond the expected curb return location.
3. Add a free curve using the alignment layout tools to complete the curb radius.

* Make your curb return alignments clockwise in direction.

Tip: Instead of Tan-Tan (No Curves), Tan-Tan (with curves) can be used with the curb radius predefined.

urbn-dsn-sml-int-04.mp4 3:04

Once the intersection geometry is created, a frequency needs to be added to the ETW setup corridor in the alignment/profile drawing. To transfer these locations back the alignment/profile drawing, several methods could be used.

• Alt 1: Create AutoCAD points at the ends of the curb radii in the corridor dwg then copy and paste them into the alignment/profile dwg.
• Alt 2: Temporarily xreference the corridor dwg into the alignment/profile dwg. Be sure to detach the xreference when finished to avoid a circular reference.
• Alt 3: Temporarily data reference the curb return alignments into the alignment profile dwg. Be sure to remove the data reference when finished to avoid a circular reference.

urbn-dsn-sml-int-05.mp4 6:40

This video is review of the curb return profile workflow covered in other training modules, but contains some slight adaptations to this scenario. It also focuses on the use of the corridor contextual ribbon.

1. Create an existing surface profile for the curb return alignments.
2. Create the setup corridor. Example name: Setup-96-CGProfiles
   • Alignment = curb return
   • Profile = Curb return existing surface profile
   • Assembly = Setup-Curb-Prof
   • Target Surface = None
3. The region limits should be where the curb radius meets the main road curb and gutter and where the curb return alignment ends along the side road (construction limits).
4. Set frequency to 2.5 and add a special frequency station where the main road edge of travel way crosses the side road centerline.
5. Target the main road edge of travel way alignment/surface profile and the side road centerline alignment/proposed profile.
6. Target the curb return alignment only.

Tip: For the adjacent curb return region, use the match parameters command to copy the frequency and target parameters from the neighboring region. Then, switch the target for the curb return alignment.

7. Create the corridor sufaces for min, max, and norm cross slopes using the corresponding links. No boundaries required.

urbn-dsn-sml-int-06.mp4 5:23

This video is review of the side road profile workflow covered in other training modules but contains some slight adaptations to this scenario.

1. We recommend turning the curb profile setup corridor feature lines to a no display style. Also set the corridor code set style to no display.
2. Create a profile view for each curb return alignment.
3. Create surface profile for each of the setup corridor surfaces (min, max, norm).
4. Create the proposed curb return profile. Using the profile layout tools, pick two arbitrary PVIs (one on each end of the alignment limits).
5. If not done already, create an surface profile on the ETW setup surface for the main road curb and gutter alignment.
6. Create an intersection object at the intersection of the curb return alignment and the main road curb and gutter alignment. Lock the curb return proposed profile (priority 2) to the main road curb and gutter profile (priority 1). Remember to uncheck the "Create or specify offset alignments" box before creating the intersection.
7. Use the profile layout tools to delete the profile tangent on the main road side.
8. At the opposite end of the proposed curb return profile, snap the PVI to the construction limits. This will be the end of the existing surface profile.
9. Add additional geometry as needed to the proposed profile using the setup corridor surface profiles as a guide. Remember profile requirements for curb ramps.