**Problem 4: Analysis**

In Problem 4, we
explored the effects of traffic-actuated control on the performance of the
U.S. 95/Styner-Lauder Intersection. Traffic-actuated control is a function of
the detection system and the signal timing active within the signal
controller at the intersection. In detailed operations analysis, the use of
detector timing presents an additional level of complexity for our analyses
and thus, may more closely reflect field conditions.

In sub-problem 4a,
we considered the effect of actuated control that revisits our assumption
regarding cycle length and phase time. This analysis assumes fully-actuated
control typical of an isolated operations.

In sub-problem 4b,
we examined the effect of unit extension on phase length and its
corresponding effect on cycle length at a fully-actuated intersection. We
learned that as the unit extension (commonly referred to as passage gap in
signal controller manuals) increases, the phase length and cycle length
increase.

In sub-problem 4c,
we revealed the implications of a coordinated operations on an actuated
signal. Specifically, the introduction of a fixed cycle length may result in
increased delay to the side street but improved operations and progression
along the arterial.

Finally, in sub-problem 4d,
the effect of left-turn protection is considered. In this analysis, we learn
how to estimate the percentage of cycles that will result in left-turn
actuation.