HomeMy WebLinkAboutG- 5 Staff Report Traffic study for 9th and Dalton and Cerritos and 6thCONSENT CALENDAR
TO: HONORABLE MAYOR AND CITY COUNCIL MEMBERS
FROM: NASSER ABBASZADEH, CITY ENGINEER
VIA: RICK COLE, CITY MANAGER
DATE: JUNE 16, 2003
SUBJECT: TRAFFIC STUDY REPORT FOR THE INTERSECTIONS OF NINTH/DALTON, CERRITOS/SIXTH,
AND MAUNALOA/FACTOR
RECOMMENDATION
It is recommended that the City Council receive and file this traffic study report for the intersections of
Ninth and Dalton, Cerritos and Sixth, and Mauna Loa and Factor.
BACKGROUND
Staff received requests to study the intersections of Ninth/Dalton, Cerritos/Sixth, and Mauna Loa/Factor
for potential traffic controls.
Existing Controls
1. The intersection of Ninth and Dalton is controlled by two-way stops in the north/south directions.
2. The intersection of Cerritos and Sixth is a T intersection and there is a stop sign on Sixth Street.
3. The intersection of Mauna Loa and Factor is controlled by two-way stops in the north/south
directions (this is a shared intersection with LA County).
Since the general vicinity of the studied intersections 1 and 3 are controlled by stop signs (please see the
attached vicinity map), staff conducted multi-way stop sign studies at both intersections. However, since
the intersection of Cerritos and Sixth is adjacent to traffic signal controlled intersections (Cerritos/Foothill
and Cerritos/Fifth), this intersection was studied for both stop signs and traffic signals.
Multi-way Stop Signs
Multi-way stop signs are posted when there is a right of way conflict. The conflict manifests itself in form
of accidents and if the accidents are susceptible to correction by installing stop signs. This type of right of
way conflict is characterized by “broad side” type collisions.
The two main warrants applicable to multi-way stop signs are:
1. An accident problem, where five or more accidents within the past 12 months have occurred and
stop signs may prevent such accidents in the future.
2. Traffic volumes, where the numbers of vehicles on all the approaches are nearly equal.
Findings
Accidents
There were no reported accidents at any of the studied intersections in calendar year 2002, nor up to
May2003. Two accidents have been reported, one a year, in calendar years 2000 and 2001 at Mauna Loa
and Factor. While, one accident was reported at Cerritos and Sixth in calendar year 2001.
Traffic Volumes
Twenty-four hour counts were taken on studied streets and the results are summarized below in the
table (count sheets are also attached).
Speed Studies
Staff conducted speed studies in May 2003 and the results are shown below.
TRAFFIC DATA SUMMARY
STREET TRAFFIC COUNTS
REPORTED
ACCIDENT
Past 12 Months SPEED SURVEY RESULTS
24 HOUR PEAK B R H POSTED AVE. 85%
4:30PM
NINTH 3,092 287 0 0 0 25 32 37
DALTON 1,656 74
6:15AM
CERRITOS 6,050 573 0 0 0 30 31 34
SIXTH 1,122 148
4:15PM
MAUNA LOA 2,541 258 0 0 0 25 27 31
FACTOR 1,726 153
Table Footnotes:
• Accidents in past 12 months: Applicable warrant study accidents.
• Speed Survey: 85% speed is by definition the legal speed to be posted on a street. Average speed indicates the
speed of 50% of motorists in the study segment.
Conclusions
A. Stop Signs
Neither the accident history nor traffic volumes support multi-way stop signs at any of the three
intersections.
B. Traffic Signal at Cerritos and Sixth
Since Cerritos at Foothill and Fifth is controlled by traffic signals, staff investigated applicability of a
traffic signal at this location as well. The State of California Traffic Manual cites 11 different conditions for
installing traffic signals. The conditions or warrants, once reduced to their basic elements, revolve around
the following main factors:
1. Excessive traffic delays
2. Relative traffic counts on the minor leg of the intersection, daily and peak hour counts
3. Interruption of continuous traffic
4. Accident experience/history
The Sixth Street traffic volume is very low compared to Cerritos: 18.5% of daily traffic and 25.8% during the
PM peak hour. Plus, there are adequate traffic gaps on Cerritos to allow Sixth Street traffic to go through
the intersection. No significant delays are experienced by the motorists on Sixth Street. The speed study
also suggests that Cerritos Avenue traffic observes the posted speed limit. Installation of a traffic signal is
not recommended at the intersection of Cerritos and Sixth.
C. Speed Limits Signs on Ninth Street
The 85th percentile speed is high on Ninth Street. A combination of new 25MPH speed limit signs and
enforcement will help reduce speeds on Ninth.
No controls are recommended at any of the three intersections.
FISCAL IMPACT
The cost to add four 25MPH signs on Ninth Street will be about $300. Public Works Department will
handle the installation of the signs.
Attachments