Two classical open source options are Inkscape and Scribus. I've used both to make pamphlets etc., and both run on Windows, Linux, and macOS.
Inkscape is a versatile vector graphics editor. It is fairly easy to get started with, but has a lot of advanced features. You have all basic shapes, polygons, line and fill styles, basic text, layers, effects like ...
Honestly, your example illustrations were all top-down vector graphics, such as can be done in Adobe Illustrator, Affinity Designer, or InkScape or Xara.
I don't think you need full-on 3D modeling, though if you do, Blender is a really great tool as mentioned before by @Steve Barnes. I fully second his recommendation.
Adobe Illustrator is an industry ...
I would suggest that if you are prepared for a somewhat steep learning curve you consider looking at Blender 3D modelling tool. While it might be a little overkill for what you are currently doing, (i.e. Plan View only), you can model your roads, intersections, etc., on a single plane initially and consider adding a 3rd dimension later.
Free, Gratis & ...
After some thought, I ended up creating a full complex pattern using an Excel spreadsheet.
I feel tremendously badass for having accomplished a task I thought I'd have depend on some CAD software and personnel who can work with it.
For anybody else that ever comes across this need and is looking for a solution, here is the spreadsheet: http://files....
Perhaps you should consider GraphViz?
You write simple text files, then run therm though the tool to draw diagrams of various sorts. Here's their example of a (very large) network (there are many more examples in their gallery).
Note that the input text file was generated by a network scanner tool. I have often coded similar programs to generate the ...
Provides rich functionality around a drawing <canvas>.
Objects (shapes) can be moved, scaled and rotated. Text fields and images are such objects, for instance.
Drag and Drop with canvas-external objects can be easily implemented. I've once done it with images which can be moved onto the canvas via the mouse.
Loading the state from JSON and ...
WordPress is a great framework to start with and is likely a perfect fit for your situation.
The following link is an article describing six great online coursework plugins for WP, most of them free. The free ones are available directly from wordpress.org, which means they have been vetted and tested by the WP community.
Online Course Plugins
The next ...
You could almost certainly produce your display with python, ipython notebooks, (Jupyter), and bokeh, your notebook can poll the data from any suitable locations and could be viewed either via nbviewer as a static page or as a dynamic page.
A nice example of the sort of thing that you can do is the Periodic Table example.
I'm a developer of windows alternative for xScope. You can try it http://rulerforwindows.com for free.
Create, layout and adjust custom marker boxes that float on top of all other on-screen elements.
Quickly and easily find the spacing between any point visible on the screen.
Magnify the area under your mouse preview color and the cross ...
I've used LibreOffice Impress as well as regular Powerpoint, where we've made stick templates of the appropriate size and orientation for students to put content into. This then gets output as PDF for the printers. Preparing the generic PPT is an effort but the consistency of output is well worth it.