Traffic Network Study Tool
Lane-By-Lane Analysis, Actuated
Control Analysis
Highly
unequal
lane utilizations are modeled more accurately when a link is defined to
represent each individual lane. For special
network locations in which traffic utilization of a given lane is
significantly
different from other lanes in the same lane group, "lane-by-lane"
modeling becomes necessary for achieving realistic results. The
Lane Configuration screen allows easy specification of lane-by-lane
analysis, and the Traffic screen allows specification of
volumes and saturation flow rates for each individual lane.
TRANSYT
contains two models for analysis of traffic-actuated control. The first model (target degree of saturation
model) is a
design model,
intended to locate the actuated phase times that would optimize the
traffic
network. The second model (actuated
estimation
model) is an evaluation model, intended to evaluate existing
conditions. The
target degree of saturation model allows actuated phases to operate in
the efficient 80%-90% degree of saturation range, while allocating
left-over green time to the major street. The actuated
estimation
model is typically used to compute phase times that are likely to
materialize in the field, based on user-specified maximum green and
force-off settings.