Iowa DOT's
policy is to be
sensitive to the environment
and foster and enhance
environmental stewardship.
IOWA DEPARTMENT OF TRANSPORTATION
Presents
ROCKS AND ROADS
Unit 4: How are highways designed?
A. Blueprints
101 -- Understand the term and how blueprints are
used.
B. Drawing
Viewpoints -- Learn about the various viewpoints and
how they are used in road construction.
C. Scale-down -- Review the definition
and reason for this in
drawing.
D. Curves -- Read about the various
types of curves and how they
affect road design.
E. Access -- Understand the different
access designs used in road
design.
F. Earthwork and Drainage -- Learn
why earthwork and drainage are
important.
G. Summary
H. Unit 4 Glossary
-- Practice using the terms and definitions
included in this unit.
I. Unit 4 Activities
-- Activities will allow students to reinforce the
informational materials covered in this
unit.
Now that we have taken a look at how engineers and planners decide where the highway should go, let's take a look at how they are actually designed. We will also review some of the issues that designers need to consider.
Highway designers create plans that are used by contractors to build the roadway. The plans must be very detailed and easy to read so the contractor builds what the designer intended.
A. Blueprints 101
Construction plans used to be, and sometimes still are, called blueprints because of the way plans used to be copied. Originals were hand drawn on sheets of special paper called vellum or special plastic called Mylar. These sheets were transparent, or see-through, and would be laid on top of another special type of paper called blue line paper. The blue line paper, which was often yellow in color, was light-sensitive and when a bright light was passed over the vellum or Mylar the areas that were clear turned white and those with writing or drawing turned blue. That is why they are called blueprints. Today plans are drawn on computer and then printed or plotted.
TO: Unit 4 B. Drawing Viewpoints
