One goal of traffic management
is to add no more than 15 minutes’
delay over normal operating
conditions, said John Davis, a
professional traffic operations
engineer and Ayres Associates’
manager of traffic engineering
services. Ayres’ specialists use traffic
microsimulation software, such
as Paramics, VISSIM, or Synchro/
SIMTraffic, to analyze how various
alternatives might affect motorists,
businesses, residences, and
construction workers. The analysis
calls for extensive information to be
entered into the software program:
the number of vehicles using the
corridor, the percentage of truck
traffic, peak traffic times, and anything
that might affect traffic flow.
“With all that information in
hand, we simulate – for example –
closing one lane of traffic to allow
construction,” Davis said. “What
happens?”
The construction staging concept,
included in the plan let to the
contractor for construction, must also
consider special events that might
affect traffic, such as a local parade or
sporting event. The plan notifies the
contractor that work schedules may
have to be adjusted to accommodate
such events.
“The contractor is focused on
getting the work done, which includes
planning the work and scheduling the
equipment and crews,” Roth said. “It
can cost them – and sometimes our
client who pays them – a lot of money
and time if they have to unexpectedly
stop work because of unforeseen
conditions. You coordinate early in
the design to address as much of that
as possible, and in the end you won’t
have as many surprises that will affect
the project.”
REGIONAL DIFFERENCES NOTED
Not all disruptions follow a
predetermined schedule. Florida
and other states affected by severe
storms have hurricane evacuation
routes designed to move the
maximum number of people to safer
regions as quickly as possible. Brian
McKee, manager of Ayres Associates’
transportation services in Florida,
notes that contractors have to ensure
that if a storm approaches, evacuation
routes under construction are quickly
open and usable, usually within 12
hours of an evacuation notice. How
to open the route becomes part of
the plan, called maintenance of traffic
(MOT) in Florida.
The people responsible for
creating TMPs have a variety of
devices and techniques at hand, with
more being added. While most
construction zone plans have common
elements to consider, the methods
used to keep construction workers
and motorists safe are tailored for
each project.
Sometimes detours become the
main focus of a TMP because the
construction zone is too cramped for
other alternatives. That was the case
in Cheyenne, Wyoming, during the
2013 construction of a roundabout on
TRENDS
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