Traffic Impact Studies
by Greg Dale
A quick overview of transportation plans, from Level 1 long-range plans for Level 4 traffic impact studies
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Read first few paragraphs of article:
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In my previous article, I gave you some background about
transportation planning and the "big picture." A specific site
analysis can only be successfully accomplished when there is a
good understanding of how that site relates to your community's
overall transportation plan.
The purpose of the traffic impact study ("TIS") itself is to
help solve a localized problem and deal with project-related
traffic within a limited area. Usually, this is the street
system immediately adjacent to the site. As the size of the
development grows, so should the area of analysis.
The TIS must answer the question: "Does the traffic generated by
the proposed development cause a decrease in service or safety?"
If the answer is "yes," then the TIS should go on to assess how
improvements can be made to mitigate the impact of the new
traffic.
Site Design
Good traffic analysis depends upon good site design. The two are
inseparable. The site planning and design process usually begins
with decisions relative to the building size and shape, and its
placement on the site. The parking and on-site circulation are
then designed around the building. Finally, the intersections of
the access drives with the adjacent street are established,
sometimes with little or no consideration being given to the
impact on the street.
When inadequate attention is given to the location and design of
access, and feedback does not occur between site design and
traffic engineering, the following problems may result: