The jargon often used by engineers can seem like a secret language.  The CAG was given a crash course in transportation engineering at the first meeting to try and bridge the jargon barrier.  One example from the meeting:

Number of Lanes  The number of lanes for a roadway are generally determined by the number of vehicles traveling the roadway during its peak hour—the single hour of the day that typically experiences the most traffic volume. The peak hour volume or design hour volume (DHV) can be estimated to be approximately 10% of the Average Daily Traffic (ADT), or the average number of vehicles a roadway section experiences throughout the 24-hour day.

In a general sense, we use the following criteria to estimate the number of lanes a

roadway requires based on the DHV (see figure above).

There are deviations from this based upon type of facility and other roadway characteristics, but the numbers above are a rule of thumb to start out with.

Other engineering considerations discussed at the meeting includes typical section, access control, capacity, horizontal alignment, vertical alignment, sight distance, and drainage.

Engineering Considerations