README

# README file for How_Traffic_Control_Signals_Work
last updated December 1, 2024

I have always been fascinated by traffic control signals.  They seem to be
very clever at keeping traffic moving safely through an intersection,
even though they have very limited information about the traffic.

Modern traffic signals, at least, must be controlled by a computer,
so it should be possible for me to write the computer program for
a traffic control signal.  I've been looking at them all my life,
so I have a general idea about how they work, but for more detailed
information I consulted the Manual on Uniform Traffic Control Devices
for Streets and Highways, a publication of the US Department of
Transportation referred to as MUTCD.

I wrote up my description of how the traffic control computer should work,
based on what I knew about what it did.  In order to be sure my description
was accurate I also wrote the program and used its output in the document.

My description, and hence my program, probably does not correspond to the
way any traffic control signal computer works, but it is useful for
explanatory purposes, and perhaps some manufacturer will decide that
what I have described would provide a better product than what he has,
and decide to use it.

To build the PDF file from the tarball, do the usual:
./configure
make

If you wish you can install the PDF on your computer for other users to see
by typing

sudo make install

The writing is licensed under a Creative Commons license, as described
in the document.  The software is licensed under version 3 of the
General Public License from the Free Software Foundation.