HomeMy WebLinkAboutNB 2 LEFT-TURN SIGNAL 08-21-89NEW BUSINESS
NO. 2
TO: WILLIAM HUSTON, CITY MANAGER
FROM: PUBLIC WORKS DEPARTMENT/ENGINEERING DIVISION
SUBJ£OT: LEFT-TURN SIGNAL PHASING AT WALNUT AND FRANKLIN
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RECOMMENDATION:
That the Tustin City Council at their meeting of August 21, 1989
authorize the modification of the traffic signal at Walnut and Franklin
Avenues to provide for left-turn phasing from Walnut Avenue to Franklin
and approve a supplemental 1989-90 budget appropriation in the amount of
$22,000.
BACKGROUND:
At the July 17, 1989 meeting, representatives from the Far West Bank
requested the installation of a separate left-turn phase from Walnut
Avenue to Franklin Avenue. As a result of this request, staff was
directed to study this intersection and perform an evaluation as to the
proper warranting of special left-turn phasing.
DISCUSSION:
The primary criteria for the satisfaction of left-turn phasing warrants
concerns the volume of left turns and the volume of "opposing" through
movements. If the arithmetic product of those volumes during a peak
travel period exceeds 100,000, then special protected phasing should be
considered.
To evaluate existing conditions, traffic counts were taken during the
morning and afternoon peak periods. The results show that several
hundred drivers turn left from Walnut to Franklin during the morning
peak hour in particular. During the heaviest peak, the arithmetic
product of these volumes with the opposing through movement is well over
the minimum of 100,000 value. This value, in combination with accident
reviews of the intersection, indicates that the installation of
left-turn phasing is appropriate. The estimated cost for this
improvement is $22,000.
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