SR-506-003-04 (4)
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5?J6- 003- 0 tf/ MAY 1 3 1980
Santa Monica, California, May 5, 1980
TO: Mayor and City Council
FROM: City Staff
SUBJECT: Main Street and Colorado Avenue Intersection Modification
Introduction
Th1S report presents a proposal to modify the intersection of Main Street
and Colorado Avenue in conjunction with the roadway and traff1c slgnal
improvements adjacent to Santa Monica Place.
Background
Prior to the October, 1980, openlng of the Santa Monlca Place, all the
traffic signals and roadway geometries are being modified, curbs and gut-
ters will be replaced, and the streets resurfaced adjacent to the shopping
center.
The existing roadway geometrics of the ~1ain Street "ylI to Colorado Avenue
is a safety problem (attachment 1). At the base of the "VII (where Mai n
Street splits north of the bridge) there have been 18 reported accidents
since 1975. Contr1buting factors to these accidents are the reduced sight
distance due to the Main Street bridge and the severe angle of the "yll
section of roadway. Si x of the acci dents were II ran-off-roadway" type of
acc1dents. These northbound vehicles failed to negotiate the lIyll and went
straight Onto the planted center med1an. There were also seven "head-on,
head-on-sidesw1pe and/or sideswlpe" accidents. These were southbound ve-
h1cles that had difficulties in negotiating the southbound turn Onto the
Main Street bridge.
The intersections of Ma1n Street, Colorado Avenue and 2nd Street, and
Ma1n Street~ Colorado and 3rd Street, have experienced 16 and 13 accidents,
respectively, since 1975. The most frequent type of accidents were slde- faN
MAY 1 3 f980
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TO: Mayor and City Council -2- May 5~ 1980
swipe and broadsides. These may be attributed to the awkward angle that
Ma1n Street intersects with Colorado Avenue. An additional problem with
this intersection is that pedestrlans on the south side of the street have
an extreme distance to cross Main Street. Presently~ pedestrian crossing
1S prohibited, but it is rarely enforced. There was a total of 22 1njuries
related to accidents on the Main Street "Y".
The projected PM peak hour trafflc volumes (attachment 2) after Santa Monica
Place opening will further compound the accident problems at the existing
intersection. Staff has provided two alternatives to improve traffic safety
and vehicular flow adjacent to Santa Monica Place.
Plan A
Plan A (attachment 3) proposes to modify Main Street to intersect Colorado
Avenue at rlght angles. This may reduce the accident potent1al by 80 per-
cent. In other words, if the proposed modificatlon had been completed prior
to 1975, 38 out of a total 47 accidents may not have occurred. The proposed
modificat1on would allow for greater safety to pedestrians crossing on the
south side of Main Street. However, the existence of three signals within
approximately 700 feet may present additional delays to motorists durlng the
necessary traffic signal clearance phases. These clearance phases provide
for a vehicle to safely clear the intersection once the traffic signal turns
to the amber phase. The estimated cost of the proposed modificatlon is
$300,000 and would be funded by the Redevelopment Agency.
The adjacent area~ which lS now part of the llyn sectlOn, may be turned into a
green area, a mini-park, and/or a transit turnout area. This wou1d further
.
TO: Mayor and C1 ty C.ci 1 -3- e May 5, 1980
augment the downtown redevelopment project..
Plan B
Plan B (attachment 4) proposes to essentlally eliminate the east leg of the
Main Street uyll connection at Colorado Avenue, with only two signals which
are 700 feet apart. ThlS will reduce the accident potential by 50 percent.
Pedestrian crosslngs would be prohibited on the south side of Main Street
between 2nd Street and the proposed Maln Street northbound right-turn-only
lane. This plan provldes for smoother flow of Main Street - 2nd Street than
the offset intersectlons of Plan A.
As traffic increases on 2nd Street, lt will become increaslngly difficult
for vehicles eXlting the parking garage at 2nd Street to make a left turn.
Plan B provides an alternative through suffic1ent storage between slgnals
to allow vehicles with southernly destinations to exit at Colorado Avenue
and enter the westbound left turn lane at the Colorado Avenue/2nd Street
intersection.
The est1mated cost for Plan B is less than $100,000 and would be funded by
the Redevelopment Agency. Any vacated street rlght-of-way may be used as
prev10usly mentloned.
Recommendation:
It is recommended C1ty Council endorse the proposed modlfication Plan B of
the Main Street and Colorado Avenue intersection and to instruct Staff to
prepare the plans.
Prepared by: Stan Scholl
Ray Davi s
Attachments: 1) Accident Diagram
2) PM Peak Hour Volumes
3) Plan A
4) Plan B
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