HomeMy WebLinkAbout03/06/1990, C-12 - TRAFFIC MONITORING STATUS REPORT MEETING DATE:
city of San Luis OBISPO - March 6 1990
'wdftQ COUNCIL AGENDA REPORT
FROM: ��
David F. Romero 5%rzvaxy 'J�°n Prepared by: Barbara Lynch'
Public Works Director City Eagineett� Engineering Assistant/Traffic`"
SUBJECT:
Traffic Monitoring Status Report
CAO RECOMMENDATION:
By Motion, Receive and File. Direct Staff to Continue to Provide Yearly
Updates and Keep Council Informed of Deteriorating Levels of Service.
BACKGROUND:
With the 1982 Circulation Element, the Council adopted a work program
priority list. One item on that list was to establish a procedure for
monitoring traffic. The intent of the traffic monitoring program is to keep
Council informed of traffic conditions on the city's major streets, using
level of service (LOS) as a guide. Level of service is the relationship
between the existing volume of traffic and the maximum amount the street can
carry (refer to Attachment 1 ). The maximum amount is determined using the
number of lanes and adjusting to account for restrictions such as on-street
parking or nearby controlled intersections.
The monitoring program ties directly into the criteria for determining the
need for major street improvements. This strategy is set out in Appendix B
of the 1982 Circulation Element and summarized below.
Step 1 is to make minor changes, such as restriping to add more lanes, to
improve flow, and make better use of the existing street, thereby
delaying the need for major improvements.
Step 2 is to notify the City Council when the level of service reaches
LOS C during the peak hour.
Step 3 is to notify the City Council when the level of service is
expected to reach LOS D in the next 4 to 6 years for all of the eight
busiest hours of the day.
In this way the Council is aware of growing traffic demand as it occurs,
prior to major congestion problems. Council can take whatever steps it deems
most appropriate to handle the problems as they become apparent.
The engineering division performs traffic vehicle counts on a regular basis.
Using past counts and those done recently to determine the rate of increase,
we have estimated the time frame in which traffic volumes will reach levels
where road changes will need to be considered to accommodate growing traffic
demands.
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COUNCIL AGENDA REPORT
Traffic Monitoring Status Report
Page Two.
Projections reflect only the average growth rate over the past several yars.
Sudden jumps in traffic, or deterioration in the LOS, may occur with
development.
RFMTS OF STUDY:
The table (Attachment 2) identifies ten major streets and the current status
of traffic volumes on these streets. Both the peak hour volumes and the
volume for the eighth highest hour are shown to indicate peak and off-peak
traffic characteristics. The eighth highest hour was decided on during the
development of the circulation element as a level which would insure the
street was being fully utilised before widening was considered. It is not a
state or federal standard.
The peak hour volume represents the highest hourly volume that occurs during
the day. The- rate at which the vehicles pass a given point may vary within
that hour. For example, morning peak may be between 7:30 and 8:30 AM but the
largest percentage of those vehicles may arrive between 7:45 and 8:00 AM.
This means that while a street may be able to carry the necessary number of
vehicles per hour there will' be times within that hour when the street will
seem overly congested. These volumes also do not reflect the extremes in
traffic such as holiday or Poly Royal traffic.
The far right column indicates the year when the eighth highest hourly volume
is projected to reach LOS D. At that time, LOS D will be reached during all
of the eight busiest hours of the day. This is used for Step 3 of the
strategy for determining the need for major changes to the streets.
Of the ten streets being monitored, Broad north of Orcutt, Chorro south of
Lincoln, California South of Foothill, and Monterey west of California appear
to have reached LOS C during the peak hour.
Projections indicate traffic volumes on the major streets are increasing at
the average compound rate of 3.23 percent per year. This will result in
these streets reaching capacity, during the eight peak hours, in the next 8
to 40 years.
CONSECIIBNCES OF NOT TAKING THE RECOMMENDED ACTION•
Staff will no longer prepare yearly updates on traffic volumes.
RECOMMENDED ACTION:
Receive and file. Direct staff to continue to provide yearly updates and
keep Council informed of deteriorating levels of Service.
b13/monitoring
by -
da . s;
res:k - STREEr 9ER7 M LEV&LS
Off'
OF VOLUME TO
CAPACITY
SERVICE DESCRIPTION RATIO
A Free flow (relatively). If signalized, conditions are 0.00 to
such that no approach phase is fully utilized by traffic 0.60
and no vehicle waits through more than one red indication.
Very slight or no delay.
E Stable flow. If signalized, an occasional approach phase 0.61 to
is fully utilized; vehicle platoons are formed. This 0.70
level is suitable operation for rural design purposes.
Slight delay.
C Stable flow or operation. If signalized, drivers 0.71 to
occasionally may have to wait through more than one red 0.80
indication. This level is suitable operation for urban
design purposes. Acceptable delay.
D Approaching unstable flow or operation; queues develop, 0.81 to
but are quickly cleared. Tolorable delay. 0,90
E Unstable flow or operation; the intersection has reached 0.91 to
ultimate capacity; this condition is not uncommon in peak 1.00
hours. Congestion and intolerable delay.
F Forced flow or operation. Intersection operates below over
capacity. Jammed. 1.00
Source: Highway Capacity Manual, REB Special Report 87
62
won" - .
Attachment 1
CAFACIiv PROJECTIONS E30U�'—"40
TRAFFIC MONITORINGPROGRAM
---------------------------
1
--
TRAFFIC DATE LEVEL PROJECTED 1
STREET NAME 1 SECTION : VOLUME COUNT : OF 1YEAR'TO REACH;
(VPH) TAKEN 1 SERVICE LOS D
1 1 PEAK 8TH 1 PEAK/9TH ; STH HIGHEST
1 1 HISHEST HIGHEST'
FOOTHILL W/O SANTA ROSA 1 1520 1245 ;10 / 1?69 ; B / A ; 2011 1
1 BROAD f N/O ORCUTT 1 2147 1804 1 7 /1989 C / B 1 1948
1 BROAD 1 N/0 PISMO ; 405 772 111 / 1989 1 A / A 2016 1
I MADONNA W/O 101 1 2785 2011 1 6 / 1989 1 A I A 1 2014 1
CHORRO 1 S/0 LINCOLN. 1312 842 ; 1 / 1990 C / A ; 2020 1
CALIFORNIA ; S/0 FOOTHILL 1401 1077 110 / 1989 1 C I A 1 .2001 1
1 CALIFORNIA 1 N/O MONTEREY 496 763 110 / 1989 1 B / A 1 2000
MONTEREY 1 W/O CALIFORNIA ; 1250 9BO 1 7 / 1989 1 C / A 1 t* 1
SANTA BARBARA 1 S/O OSOS f 1169 844 1 2 1 1989 1 A / A 1 2011
1 JOHNSON 1 N/O LIZZIE 1 1802 1455 1 9 1 1984 ; B / A 1 2023 1
1 LOS OSOS VALLEY 1 W/O HISUERA ; 1134 836 1 .2 / 1990 1 A / A 1 2007 1
1 HIGUERA 1 S/O MADONNA 1 1527 1115 1 1 / 1990 1 B / A 1 2011 1
1 1 1 1 1 1 1
1 1 l 1 I 1 1
----------------- ------------------
t+ No change in volume. Street is not projected to reach
capacity ander the current growth rate.
,1
Attachment 2