CadCraft™ v0.9.0
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Intersections and traffic

Junctions, striping, signs, signal timing.

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Screenshot from the lab build. Intersections and traffic in CivilCraft: a four-leg junction with three-centre curb returns and crosswalks, and center and edge lines painted along the alignment, on the
Screenshot from the lab build. Intersections and traffic in CivilCraft: a four-leg junction with three-centre curb returns and crosswalks, and center and edge lines painted along the alignment, on the
The striping result: painted lengths and area, and the signs placed along the alignment with their codes, stations and sides
The striping result: painted lengths and area, and the signs placed along the alignment with their codes, stations and sides

Overview

Intersections and traffic lays out a road junction with curb returns, works out its intersection sight distance and sight triangles, and draws pavement markings and signs along an alignment, with the painted lengths and areas. It is a design aid for road layout. It does not time signals.

Who it’s for

  • Road and civil designers who lay out junctions, curb returns, and the lines and signs on a road.
  • Traffic engineers who want the sight distance and the sight triangles for a junction.
  • Quantity surveyors who need the painted lengths and areas.

What you can do

  • Lay out a junction of two or more legs with curb returns of a set radius (Surface, More, Junctions and striping). The result gives the tangent length, arc length and pavement area of each corner, and the curb return length.
  • Work out the intersection sight distance for a design speed and a gap time, for a left turn from the minor road, and the sight triangles of the minor legs checked against obstacles that you draw.
  • Paint lines along an alignment: double centre lines, lane lines and edge lines, with dashed lines and gaps at the junctions, and crosswalks.
  • Place signs along the line and get a sign schedule with positions and counts.
  • Export the roads as a DXF drawing.

Methods and standards

Curb return as a simple radius between the two edge lines: the tangent length is r over tan(psi/2) and the arc angle is pi minus psi. Intersection sight distance ISD = 0.278 times V times t, with V in km/h on the major road and t the gap time in seconds (7.5 s for a passenger car, plus 0.5 s for each extra lane crossed), from AASHTO Green Book, 7th edition, chapter 9, case B1. The sight triangle is bounded by the two legs and the line between their ends.

Data and sources

Design speeds, gap times, lane widths, paint widths, dash lengths and sign sizes are settings with placeholder defaults. The authority's standard (MUTCD, TSM or the national manual) fixes each limit, so you set these numbers for your project.

Verification

Tested by bin/test-civilcraft-intersection.mjs with known answers worked by hand: a 90 degree corner (tangent length, arc length and cut-off area), a 60 degree corner, a four-leg crossing of two 12 m roads with 9 m returns, the sight distance at 60 km/h with a 7.5 s gap (125.1 m), a dashed line of 3 m dashes and 9 m gaps over 120 m, and a double centre line. Not yet checked against a reference junction from a road design package.

Limits

A calculation aid, not a design. The standard in force fixes the limits. There is no signal timing, capacity analysis or traffic simulation. The sight distance covers the case stated above; other cases are not in it. The add-on does not choose the sign sizes or the markings for you.

Files and formats

Reads the alignment or polyline that you draw or choose in CivilCraft. Junction and striping items are saved with the project. Exports the road drawing as DXF.

Get started

  1. Open CivilCraft, then Surface, More, Junctions and striping.
  2. Add the legs of the junction with their widths and the design speed. The curb returns and the sight distance update.
  3. Add a striping item along an alignment, then export the roads as DXF.

Languages

No languages are listed for this add-on yet. Its maker may add some.

Works in

EditionWorksNote
Browser (/use) (yours) Added on demand Fetched the first time you use it, then kept for offline use.
Studio from getcadcraft.com Added on demand Fetched the first time you use it, then kept for offline use.
Microsoft Store Added on demand Fetched the first time you use it, then kept for offline use.
Google Play Added on demand Fetched the first time you use it, then kept for offline use.
iPad and iPhone (App Store) Included; switch it on Part of the reviewed app; your list switches it on.
Custom build Added on demand Fetched the first time you use it, then kept for offline use.

Comes with

Nothing else.

Needed by: Civil and site engineering, Transportation and traffic engineering.

Versions

VersionChannelDateWhat changed
1.0.0stableOctober 28, 2026First version in the Library.

Licence and maker

CadCraft (CadCraft, first-party). Licence: Apache-2.0. Dependencies carry their own licences, listed on their pages.