Earlier study results confirmed in re-test
To Commission Additional Traffic Study
August 6, 2002--
University of Virginia has accepted the city of Charlottesvilleıs
recent recommendation in a letter to the Department of Environmental
Quality that U.Va. pay for a new traffic study before the Emmet
Street parking garage opens. A mutually agreed-upon firm will conduct
the study using traffic data collected this fall.
hope the next study will resolve any remaining doubts about the
data and assumptions used in the first one," said Colette Sheehy,
U.Va.'s vice president for management and budget.
"We expect it to be more detailed than the planning
study, and will help us develop and refine operating strategies
for the garage and to determine the best timing, phasing, and synchronizing
of the traffic signals at the entrances and nearby intersections."
In addition, Sheehy said, the University has contracted
with Parsons Brinkerhoff, one of the worldıs largest engineering firms
that specialize in transportation and planning, to advise on operational
matters, such as lane configurations and the placement and use of
proposed traffic signals. New
traffic counts at the Emmet-Ivy intersection will be taken this fall
as part of their work.
Sheehy also announced that the traffic
consultants who conducted the Universityıs first full traffic study
-- the North Grounds Transportation Synthesis Study done in June
-- have completed a re-testing of their earlier
to questions raised by traffic experts hired by the city and a group
of local residents to review U.Va.'s initial traffic study, the
Glatting Jackson firm re-ran many of the analyses, revising the
methodology as the other experts had suggested. Using the recommended
factors, however, did not change the original conclusions, said
Walter M. Kulash, a senior partner at the Orlando, Fla.-based firm.
example, we recomputed the traffic performance of the Emmet Street-Ivy
Road intersection following all of the recommendations of the reviewers,"
Kulash said. "While
the average delay increased slightly, from 41.5 to 49.1 seconds
in 2003 and from 38.0 to 44.1 seconds in 2006, the overall level
of service at that intersection did not change. It is still at a
level considered reasonable for an urban area."
the request of U.Va. planners and local residents, Glatting Jackson
also produced a computer simulation of current traffic-flow conditions
at that intersection. This
new simulation, when compared with a model of future conditions displayed
at a public meeting in May, shows the positive effect of synchronizing
traffic signals and other proposed improvements in the area, Kulash
model shows that existing conditions are, in fact, worse than those
shown in the 2006 model after the three projects [the garage, a
new arena and a future garage in the arts complex] and the North
Grounds Connector are complete," he said.
information was collected for the original study, the city changed
the timing and the phasing of the Emmet Street-Ivy Road traffic light
-- increasing the average wait time to its present 52.4 seconds --
to allow pedestrians more time to cross. The
average delay previously had been calculated at
26.4 seconds. (The revised study allows for this increase.)
Glatting Jackson also addressed the reviewersı concern
that a proposed traffic signal at the garageıs Emmet Street entrance
would be too close to the light at Ivy Road, possibly violating
Virginia Department of Transportation standards.
"We contacted an engineer in VDOTıs traffic operations
division for the departmentıs signal spacing criteria," Kulash
said. "She said
that while there are criteria for signals on rural roads, VDOT has
no formal policies or guidelines for urban areas.
They evaluate proposed signals in such locations on a case-by-case
basis, using principles established by a national manual on traffic
noted that signals in built-up urban areas are commonly less than
1/4 mile apart, reflecting the small size of downtown blocks or
parking garage entrances at mid-block.
A local example is the 2nd Street signal for the Water Street
garage, which is less than 150 feet from the light at the Water
Most of the comments made by reviewing engineers,
he said, asked for a level of detailed analysis normally found in
an operational study, not at the planning level. Nevertheless, when they applied the suggested operational-level
detail to a sample of their analyses as a test, it did not change
Carol Wood, (434) 924-6189