HomeMy WebLinkAboutNB 4 TRAFFIC CONTROL 06-02-80OATE;
TO:
FROM:
SUBJECT:
MAY 20, 1980
NEW BUSINESS
No. 4
6-2-80
Inter-Corn
DAN BLANKENSHIP, CITY ADMINISTRATOR
NORMAN HOWER, TRAFFIC ENGINEER
TRAFFIC CONTROL - SILVERBROOK DRIVE AND COPPERFIELD DRIVE AREA
An investigation of the area of Copperfield Drive, Sandbrook Drive, Birchfield
Drive and Silverbrook Drive has been done as requested in the attached letter.
As shown on the attached drawing, there is a through connection between Walnut
Avenue and Red Hill Avenue by using these streets. All of the streets are fully
paved with 36' of pavement, parkway, and sidewalks. There are two uncontrolled
"T" intersections in this area. The development is residential in nature.
The primary complaint of the residents is the amount of through traffic, speed,
and accidents. This area has been observed for a total of 7 hours over a period
of several days and at various times of the day.
This route appears to be taken by a n~nberof high school students on their way
to and from school. They walk, ride bikes and mopeds, and drive through the
area. There is some noise and speed associated with this movement. Observa-
tion did not indicate any great amount of other through movement, though there
is undoubtedly some, especially at peak periods when Walnut Avenue at Red Hill
Avenue is congested and backed up. Traffic counts, which were low, did not
show volumes that would be above normal for this type of development.
Stop control investigations at the two "T" intersections of Sandbrook-Birchfield
and Silverbrook-Birchfield showed that these intersections did not meet the war-
rants for 3-way stop control at any hour of the day. Observation indicated that
it is very seldom that two vehicles were in the intersections at the same time.
There has been a total of five reported accidents in the area since January l,
1977, as shown on the collision diagram. None of the accidents were intersec-
tion accidents and most appeared to be due to loss of control or inattention.
Radar was used to determine existing speeds, but some difficulty was experienced
in obtaining a fair sampling due to the very low traffic volumes and only a very
minimal amount of vehicles were sampled. Due to the very short distances in-
volved, the speeds on Silverbrook, Birchfield, and Sandbrook were within reason.
Speeds on Copperfield appeared to be high and observation seemed to indicate
that a considerable amount of this was being done by the residents themselves
or vehicles oriented to these residences rather than through traffic.
There is a certain amount of on street parking throughout the area and drivers
have a tendency to drive down the center of the street except when meeting another
vehicle. The children in the area cross the street wherever they please, usually
without looking. Children also have a tendency to play in the street.
DAN BLANKENSHIP
May 20, 1980
Page 2
It cannot be recommended that stops be installed at the two intersections since
they did not meet the warrants. Installation of stops at these intersections
would do nothing to control the speed on Copperfield and would in all probabili-
ty, be mostly ignored due to very low volumes and good visibility. If the con-
gestion on Walnut at Red Hill was relieved and free movement obtained there, that
might discourage some of the movement through these streets.
NORMAN HOWER
Traffic Engineer
NH:rrm
Attachments
STANDARD WARRANTS FOR 4-WAY STOP CONTROL
IN USE BY:
U.S. Department of Transportation
State of California
Any of the following conditions ma~ warrant a four-way stop sign
installation:
Where traffic signals are warranted and the need is
urgent, the four-way stop can be used as an interim
measure until a traffic signal can be installed.
An accident problem, as indicated by five or more reported
accidents of a type susceptible of correction by a four-way
stop installation in a 12-month period. Types of accidents
susceptible of correction include right angle and left
turn collisions.
3. Minimum volume warrant:
The total vehicular volume entering the intersection
from all approaches must average at least 500 vehicles
per hour for any eight hours of an average day, and
The combined vehicular and pedestrian volume from
the minor street or highway must average at least
200 units per hour for the same eight hours with an
average delay to minor street vehicular traffic of
at least 30 seconds per vehicle during the maximum
hour.
c. When the 85-percentile approach speed of the major
street traffic exceeds 40 miles per hour, the
minimum vehicular volume warrant is 70 percent of
the above requirements.
At a "T" intersection (3-way) a minimum vehicular volume of 75 percent
may be used. (Total vehicular volume of 375, minor street volume of
]50.)
TRAFFI~
INTESECTION OF BIRCHFIELD DRIVE AND SANDBROOK DRIVE
E.B. W.B. BIRCHFIELD S.B.
IME BIRCHFIELD BIRCHFIELD TOTAL SANDBR00K
2'.-~0 1:00 A.M. 0 5 5 0
~:u0 - 2:00 0 0 0 0
2:--'0 - 3:00 0 0 0 0
S:00 - 4:00 0 0 0 0
'~: 0 - 5:00 0 0 0 5
5'-~0 - 6:00 5 0 5 0
$:U0 - 7:00 0 10 10 5
7 ~0 - 8:00 10 40 50 25
3:00 - 9:00 5 15 20 15
9 )0 - 10:00 5 5 10 5
~:00- 12:00 5 10 15 10
2--)C-'~ i:00 P.M. 5 10 15 10
L:00 - 2:00 5 10 15 10
2 30 - 3:00 20 20 40 25
~'--00 - 4:00 15 35 50 35
2:00 - 5:00 5 25 30 35
5 ~0 - 6:00 30 50 80 35
~:00 - 7:00 5 15 20 15
~ 00 - 8:00 25 20 45 10
.3=-00 - 9:00 5 15 20 15
~;00 - 10:00 0 5 5 10
~( 00 - 11:00 0 0 0 10
~1:00 - 12:00 0 0 0 5
TOTAL 145 300 445 290
INTERSECTION
TOTAL
5
0
0
0
5
5
15
75
35
15
20
25
25
25
65
85
65
115
35
55
35
15
10
5
735
THIS INTERSECTION DOES NOT MEET THE WARRANTS FOR STOP CONTROL DURING ANY HOUR
OF THE DAY.
?IME
12-90 1:00 A.M.
1:00 - 2:00
2 )0 - 3:00
3:00 - 4:00
4 ~0 - 5:00
5'-90 - 6:00
6:00 - 7:00
7 )0 - 8:00
8:00 - 9:00
9 )0 - 10:00
9--90 - 11:00
i:00 - 12:00
? )~ 1:00 P.M.
1:00 - 2:00
2 )0 - 3:00
3--90 - 4:00
4:00 - 5:00
5 )0- 6:00
6:00 - 7:00
7 ]0- 8:00
8--90 - 9:00
9:00 - 10:00
~C ]0 - 11:00
TOTAL
TRAFFIC VOLUMES
INTERSECTION OF SILVERBROOK DRIVE AND BIRCHFIELD DRIVE
moSo
SILVERBROOK
0
0
5
0
0
0
5
5
15
5
5
5
5
10
10
15
~5
25
5
5
0
155
S.B. SILVERBROOK E.B. INTERSECTION
SILVERBROOK TOTAL BIRCHFIELD TOTAL
5 5 0 5
0 0 0 0
0 5 0 5
0 0 0 0
0 0 0 0
5 5 5 10
15 20 10 30
15 20 30 50
10 25 20 45
5 10 5 15
10 15 15 30
10 15 5 20
5 10 10 20
5 15 20 35
10 20 15 35
10 20 15 35
10 20 15 35
10 25 5 30
15 40 10 50
15 20 5 25
20 25 5 3O
0 5 10 ~15
0 5 5 10
0 0 5 5
175 330 220 550
THIS INTERSECTION DOES NOT MEET THE WARRANTS FOR STOP CONTROL DURING ANY
HOUR OF THE DAY.
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0
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RECEIVED