Proposed Traffic mit 001heffran
MEMORANDUM
Date: April 16, 2004
To: Erling Birkland, Yelm Schools
CC: John Erickson, Erickson McGovern Architects
From: Marni C. Heffron, P.E., P.T.O.E;~
Subject: Yelm High School and Junior High School
City-Proposed Transportation Mitigation
The City ofYelm presented its "pmliminary traffic mitigation measures" iu en a-mail dated April 12, 2004. [
have listed [hose measures below along with my evaluation oC them.
High School
1. Half street improvements to the urban arterial s[audard along [he High School's SR 507
(correct location is SR SIOJ frontage.
This measure was expected and is reasonable.
2. A dedicated left turn lane on westbound SR 507 at 93r0 Street (correct location is SR 510
at 93r° StreetJ.
The W SDOT has already proposed to improve [his intersection [o add the westbound-to-
northbound lefr-tour lane. The City oCYelm should allow the school district [he flexibility to
partner with WSDOT to have this improvement installed.
3. A two way left taro from the end of the dedicated left turn at 93'tl Street to 250 feet east
of the eastern access to the High School.
Our analysis did recommend that the left-tam lane be installed on SR 507 for a length of 250
feet east of the eas[em High School access. This length was determined based on the volume
of traffic projected to use [hat driveway.
We also recommended extending the two-way-lefr-tam lane on SR 510 west of [be northwest
driveway; however, only about 100-fee[ of storage space would be needed [o provide the
operational benefits Cor vehicles taming left from the site. Our analysis stated that
"Alternatively, the Yelm Community Schools could pay a proportional share towards
WSDO"f's project to improve the SR 510/93rd Avenue iutersectiou ifthat pmjec['s left mm
Zane can be extended east [o serve the uorthwestem school driveway." The Ciry's suggestion
that the School Disnict fund/build [he entire left-mrn lane exceeds your fair-share of the
burden The City should provide you with the flexibility [o par[uer with the state to have the
6544 NE 61st Street, Seattle, WA 98115 Phone: (206) 523-3939 Fax (206) 523-4949
City-Proposed Mitigation Measures t C'l~ }}
April 14, 2004 J. } t__~ ~ ~ C~l~
Page 2 oI2
full improvement constructed; however, if that parmers}tip cannot be formed, the minim[rm
required should he a short extension of the two-way-left-taro lane.
New Junior High School
4. The connection of 1070i anU Carter Strcet as a public street.
I believe that the right-of-way requirement and additonal dminege requirements for such a
public street may render this already-too-smell site unusable Cor a school. In addition, it may
aeate an additional safety and security hazard for school-age children who may have to cross
this pubhc street m acces's' the sports fields.
5. A 250 fwl dedicated left [urn lane on southbound SR 507 at Carter Street (the
developer of Hawks Landing is required [o construct a 100 fool dedicated left turn lane
at this location, the district would extend it 150 additional feet).
W SDO'C's standards fox [he volume oC left-taming end opposing traffic on SR 507 (including
school related vehicles) would require a tam lane with 100-feet of storage. Thus the mm lane
proposed by Hawks Landing would be adequate for both projects.
6. Half street improvements to the neighborhood collector standard along Mill Road.
The proposed site has no frontage along Mill Roed. To my knowledge, there are no
development regulations that would reyuire half-snee[ improvements along this roadway.
In addition, the school is being designed so that almost all access would occur directly [o SR
507. The exception may be buses that would use Mill Road as part of a loop. The smal]
number of buses [he school would add to this street would not warrant half-street
improvements.
7. Review of the traffic at Mill Road with and without the connection of Carter/107`" to
determine if the realignment oC the intersection is warranted.
The analysis oCMill Road/SR 507 was performed aswming NO connection from Carter to
107th (see response to N4 above). Ho realignment would be needed without this connechon
since very little school traffic, if any, would use Mill Road.
Off-site Improvements -
8. Res[ripe SR 507 west of the intersection of SR 507 and SR 510 (Yelm Avenue and First
Street) to extend the center turn lane to Edwards Street with a dedicated left turn t0 at least
Railroad Avenue.
The proposed school projects would add one (1) trip to this left-Nm movement during the AM
and PM commuter peak hours. During the period inmrediate after school (the school PM peak
hour), the projects would reduce the volume making this left-mm movement. For all lime
periods, the projects would also reduce the haffic opposing this left-mm movement (the
westbound through movement on Yelm Avenue). TmCfic operations analysis performed for this
intersection de[emtined that the school projects would not adversely affect the level ofservice; in
fact during [he AM and school PM peak hours, the projects would reduce vehicular delay.
Rased on the haffic operations analysis and [he fact [hat the school would add little to no haff~c
to the left-tam lane, the School District should not be required to implement this improvement.
MCH/mch