All state roads are designated with a functional classification that identifies how they are seen to fit into the overall road network. Functional classifications are developed for an entire statewide
system at once. There is some legitimacy to traffic planners’ resistance to changing the functional
classification during the development of a particular project. It is usually considered a planning, not a project, function and oftentimes is revisited no more than once a decade. Additionally, de- sign manuals at all levels of government, as well as the authoritative American Association of State
and Highway Transportation Officials’ (AASHTO) “A Policy on Geometric Design of Highways and Streets,” otherwise known as the “Green Book,” are based on functional classification. The AASHTO Green Book states, “The first step in the design process is to define the function that the
facility is to serve.” As a practical matter, however, for work on existing roads, the classification has already been predefined at the statewide level, perhaps as much as a decade earlier.
You may need to push your DOT to think about the road in its fuller context, as opposed to what they see in their functional classification maps and tables. This is because assigning functional clas-
sification is not an exact science—it requires a lot of subjective judgment, even if it is based on fact. There is also a lot of overlap in the different classes of roads, and there is a tendency among trans- portation officials to designate an entire length of roadway as one functional classification, even if it clearly serves different functions as it passes from town to town.
For example, Route 1 is classified throughout New Jersey as a principal arterial. Yet, on its path from
Trenton near the Pennsylvania border to the George Washington Bridge into New York City, Route
1 functions very differently depending on what communities it is passing through. Between Wood-
bridge and Trenton, for example, Route 1 serves as a critical regional facility, providing a much- needed connection for moving goods and people between Trenton, Princeton and New Brunswick. Farther east, where Route 1 is essentially paralleled by the New Jersey Turnpike and the Garden
State Parkway, Route 1 is relegated to a more local function as it passes through a number of North Jersey communities.
Why should you care about this? First and foremost, most roadway design manuals are based on
functional classification. The classification directly affects the flexibility in the range of design op-
tions for a particular roadway section. The higher the classification, the more rigid guidelines in the
design manuals become. For instance, the specifications of lane and shoulder widths are stricter for major arterials than for collectors and local streets.
The functional classification system shapes how DOTs think about and design roadways. Advocates for change need to get DOTs to think outside the narrow box that functional classification cre-
ates. What they sometimes seem to forget is that functional classification is often quite different
on paper than the actual function of a road in the real world. Designing roads based on functional classification favors high-speed designs even when conditions on the road itself might not warrant
it. More simply stated, your DOTs will be far less likely to design a roadway to minimize its negative
impacts on local communities for highways classified as having regional or statewide significance. You should be able to find functional classification maps, or at least information about how to find
them, on your DOT’s website.
Some states are beginning to explore classification systems based solely on the role of the highway
segment in question. Massachusetts Department of Highways is a leader in this philosophy, having
introduced area types as a factor in their design process, to be considered along with the road-
way type. Their revolutionary Project Development Manual can be seen at: http://www.mhd.state. ma.us/default.asp?pgid=content/designGuide&sid=about.
Pennsylvania DOT and New Jersey DOT, in partnership with the Delaware Valley Regional Planning
Commission—the Philadelphia MPO—are also in the process of institutionalizing this thinking in
a landmark document called the “Smart Transportation Guidebook for Pennsylvania and New Jer- sey,” which can be downloaded at http://www.dvrpc.org/asp/pubs/reports/08030A.pdf.
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