Intersection Design

[civil3d.wishlist1941]

Summary: I wish Civil 3d had it's own intersection/Cul-de-sac,knuckle design tool built into the interface.

Description: I wish Civil 3d had it's own intersection builder built into the interface. There is a toolbar that you can purchase from a company that builds the curb returns with the alignment and profile based on the information you put into the spread sheet. I wish Civil 3D would make it's own intersection builder that could be put in under the corridor menu.

How Used: I would be able to create the curb returns quickly based off of the finished profile of two intersecting roads. It would automatically create the alignment and profile making the design of an intersection faster and easier.

Feature Affinity: Corridor Modeling

Submitted By: Justin Schnadelbach on August 23, 2007

[jpaulsen]

I would like to see the corridor models support intersections, and cul-de-sac (turnarounds).

I would use the wish to simplify subdivision roadway grading and layout. I would also use it to ease the tie in of side streets.

(Submitted by: Stan Adkerson)

[jpaulsen]

Civil 3D needs an intersection design module that is not station based but rule based. What typically happens in intersection design is that a person uses AASHTO or other ruling agency and selects the appropriate curb return style, right and/or left turn bay lengths, transition tapers, pork chop islands, walks and ped ramps etc. and then hand drafts these elements. Once it is drafted 2D they then pick off the stations (station based), for the critical points pull the elevations from the profile and hand calc the elevations at the edge of pavement and then starts figuring out how the curb return profile will look. Then you need to figure out how the minor road cross-slope transitions to meet the profile grade of the mainline roadway. All of these aspects of intersection design from the horizontal to the cross-slope transitions are rule based. One uses the rules to arrive at the stations. One does not use the stations to arrive at the rules!

In order to use the rules to design an intersection there are only three pieces of data necessary to begin the design. These are: 1) The two or more alignments intersection point, 2) The two or more alignments corresponding profiles, and 3) The two or more alignments typical cross-sections. From these three elements rests the whole intersection design. Civil 3D already knows these three elements. Civil 3D just needs a design module that allows one to input all the intersection design rules into a dialog box and then Civil 3D could generate the intersection based on these rules! Then if the mainline or side street alignment is moved Civil 3D could then automatically figure the new alignment intersection and regenerate the intersection based off of the design rules established for that intersection. This module also should generate the curb return profiles and allow minor tweaks to be made to the profiles that would update the intersection to accommodate for all the little drainage issues that come up in an intersection design. This is a huge request but needed. Most roadway design time is spent in the intersections. After this is done we need to look at a roundabout design module….

(Submitted by: Arthur Miller)