| Contextual Infrastructure Planning and Design |
| History Meets Highway: Making U.S. Route 1
Safe Again |
| By Jim Maloney, Philadelphia, Pennsylvania 1-215-790-2331,
maloneyj@pbworld.com, Jennifer
Diec, 1-215-790-2312, diec@pbworld.com
and Carol Martsolf, 1-215-790-2319, martsolf@pbworld.com
|
| In the southeastern portion
of Pennsylvania, U.S. Route 1 traverses historically significant battlefields
that date from the American Revolution. Recently, that stretch of
highway had become unsafe, and so PB and the Pennsylvania Department
of Transportation implemented various improvements that satisfied
safety, aesthetic and historic concerns. |
|
U.S. Route 1 is a multi-lane major arterial that extends from Florida
to Maine, traversing Pennsylvania along the way. It was the major
north-south highway route in the eastern U.S. prior to construction
of I-95 approximately 40 years ago. Currently, U.S. Route 1 carries
approximately 24,000 vehicles each day in the project area, a 22.5-km
(14-mile) section in Chester and Delaware Counties, Pennsylvania,
approximately 32 km (20 miles) south of Philadelphia. It bisects the
five historic districts present in its corridor, including Brandywine
Battlefield, a revolutionary war site that is now a National Historic
Landmark, and it bisects a land conservancy.
In recent times this stretch of highway has surfaced as a battlefield
of a different nature, a place where a staggering number of vehicle
accidents occurred. The Pennsylvania Department of Transportation
(PennDOT) retained PB to study the roadway and accidents and recommend
safety improvements.
Straightforward
Solutions
While doing the safety study, we found that many of the accidents
could be attributed to vehicles either making left turns at unprotected
intersections or crossing over the existing mountable concrete curb
median, particularly in areas where the region's rolling terrain limits
sight distance. One solution in settings such as this one would call
for widening the median. In this area, however, such a solution was
difficult because a widened pavement surface would greatly impact
the battlefield, historic structures and natural resources of the
land conservancy, as well as numerous local residences and businesses.
We suggested in our final recommendations that the best ways to reduce
the high accident rate included installing a concrete median barrier,
closing numerous median openings and constructing intersection upgrades.
As a follow-up, we were retained to provide final design services
for those recommendations.
Satisfying
Community's Aesthetic Concerns
In coordination with PennDOT, we met regularly with local residents,
businesses and community representatives to discuss the projects and
their impacts on this historically sensitive area. While generally
giving support to the project, the public was concerned about how
it would affect the aesthetics of the community. Specific concerns
were voiced regarding the placement of the concrete barrier and disturbance
to landscaping that surrounded area residences, many of which date
from the mid-1700s.
In order to eliminate unnecessary, and in many cases, unsafe crossings
of the highway into properties, driveways and local streets, our design
utilized jug-handle style adaptations at two existing intersections.
These adaptations allowed drivers to safely access these points through
u-turns at signalized intersections rather than through the numerous
openings in the median, which were locations with high accident rates.
Even though these locations are within the National Historic Landmark,
the coordination efforts we made with the Department and various other
regulatory agencies to obtain environmental clearance were successful
in ultimately obtaining a categorical exclusion to perform the construction.
For areas that warranted protected left-turn lanes, we developed plans
in association with individual owners to creatively replace landscaping
that was affected and, in several cases, add new landscaping. During
this phase, our design team met with the property owners on site to
discuss the proposed construction and mitigation measures.
A much more challenging aspect of the project was adding the concrete
median barrier while enhancing the visual aesthetics of the roadway.
The barrier, which was required to reduce crossover accidents (in
lieu of extensive widening) would be considered unsightly in an area
dotted by historic structures, so we focused on methods to make the
barrier more attractive.
Our recommendation was a modified concrete median barrier that featured
an exposed aggregate construction, similar to that used commonly on
sound barrier walls. The bottom half, where the wheels of the impacting
vehicles typically make contact, would have a typical concrete finish
for two reasons:
- If the bottom half also featured exposed
aggregate, an accident could cause the stones to break loose and
create an additional hazard.
- Any damage to the exposed aggregate would require replacement
of the ten-foot lengths of barriers more frequently, thus increasing
the maintenance costs.
Both PennDOT and the public found this solution acceptable.
A Unique Solution for a Unique Situation
Another challenging area of this project was near the entrance to
the Brandywine Battlefield State Park. This park, part of the National
Historic Landmark, commemorates the largest land battle of the American
Revolution-a battle that was fought by prominent generals (Washington
and Howe) and that featured the introduction of the Ferguson breech-loading
musket.
The entrance to the park was located very close to another intersecting
road, creating an awkward offset intersection that featured two median
openings with no protected left-turn lanes. After extensive coordination
with the park's administrators and the Pennsylvania Historical and
Museum Commission, PB and PennDOT recommended relocating the park's
entrance to align with the neighboring intersection, and providing
a protected left-turn lane from Route 1.
Extensive grading and landscaping were required not only to maintain
the park entrance's aesthetics, but to improve them while maintaining
the entrance's accessibility to the many tourists, school children
and visitors who the park welcomes. We designed new, colorful entrance
and advance signs to enhance the visibility of the entrance and make
it more noticeable to passing vehicles (Figure 1). As part of our
interdisciplinary involvement on this project, we were also involved
in evaluating landscape architectural issues as well as the design
conditions.
Figure 1: Example of new advance signs |
We faced another challenge on the opposite side of the highway, where
an open space preserve owned and maintained by the Brandywine Conservancy
is located and where roadway widening was required in order to install
left-turn lanes. Harvey Run, a tributary to the nearby Brandywine
River, crosses Route 1 within the Chadds Ford Historic District and
within the National Historic Landmark. Over time, as Route 1 grew
from a narrow horse and buggy path to a major vehicular arterial,
the tributary was displaced, eventually shifting to its current location
immediately parallel to the toe of the roadways embankment. This shift
resulted in an unnatural situation that allowed pollutants from the
roadway to overtake the tributary and peak flows to undermine the
Route 1 roadway embankment.
In such a situation, the stream would typically be shifted parallel
to its current alignment to accommodate for the widening and minimize
right-of-way acquisition. The need to minimize impacts to this sensitive
area prompted PennDOT, the local soil conservation district, PB and
our subconsultants, to work closely with the Brandywine Conservancy,
Pennsylvania Department of Environmental Protection and the U.S. Army
Corps of Engineers to create a new, more natural alignment for the
stream through the Conservancy's property.
Diverting the alignment into the conservancy was not only a way to
restore aquatic and vegetative life; it also provided a perfect location
for creative landscaping of new wetlands. These wetlands, which were
required to mitigate wetland losses elsewhere along the highway, allowed
the Conservancy to use the relocated stream as a focal point for a
proposed hiking path that will soon become a reality.
Successful
Results
Innovative design such as the special median barrier, distinctive
signs and creative landscaping, enabled PennDOT and PB to improve
safety on this busy stretch of roadway while mitigating the effects
to, and in some cases improving, the existing resources that it traverses.
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Jim Maloney, a Civil Engineer, worked as a design
engineer for the final phase of the Route 1 corridor. He is also currently
chair of PB's Professional Growth Network.
Jennifer Diec, a Senior Civil Engineer, served as a project engineer
on the Route 1 project and is currently a project engineer on several
PennDOT projects.
Carol Martsolf, a Design Engineer for transportation projects, she
is currently the President of the Younger Member Forum of the American
Society of Civil Engineers, Philadelphia Section. |
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