Design

Notes

Davius places high value on SE, however the balance of the subject will be covered here (under Design) and on the next page (development).
Further discussion is offered in the discussion of CAV Systems per se.

Design may be thought of as more art than science, but several principles apply which are useful in the case at hand.

• Identify subsystems and interfaces,
• Write subsystem requirements, including functions, qualities, and constraints,
• Design subsystems, and
  
• Observe standards.
  

The discussion of freeway design at right is intended to indicate the importance of standards for highway and freeway design and the engineering skills required to perform the designs. It is included to indicate the depth of transportation-system design.

Specify details
Designs typically include such details as

• materials for roadway surfaces, drainage culverts and pipes, bridges and tunnels, and all relevant structures, and for network cables and transceivers,
• programming languages and documentation (for node and network software), etc.
• protocols for the various layers of the network
• and much more.

For CAV Systems on this site, details such as the above are held to the minimum necessary to clarify concepts.

As we lay out the high-level design, we will clarify where we need stability (at interfaces) and where we need flexibility (within layers). We can use experience - for transportation that means knowledge of existing roadways, railways, and airways - and intuition, including incorporating other disciplines, such as digital communications networking, navigation, and protocol development.

A few words about freeway design
Back in the 20th century, when they were still being built in California, freeways went through several steps from conception to realization.

1. Once the demand for a freeway was perceived, the state department of transportation (Caltrans, or predecessors in California) would draw the line, connecting the two extreme points of the freeway.
2. An Advanced Planning team would then make on-the-ground observations of topology and existing construction (schools, businesses,  residences, etc.) to refine the line.
3. CalTrans would assure that needed right-of-way was made available.
   
4. Then, freeway designers would draw the freeway specifications including lanes, shoulders, bridges, tunnels, ramps, drain pipes, etc, using
   1. area contour maps showing topology and right-of-way,
   2. requirements for roadway geometries, nodes, bridges, and tunnels, and
   3. standards for materials, grading, drainage, banking, curve radii, etc.