HomeMy WebLinkAboutCorrespondence ENG 3/11/2011 Branch Engineering , Inc .
Corporate Headquarters Salem Engineering Office Principals
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Springfield,OR 97477 Salem,OR 97301 Renee D.Clough,PE,PLS
• Rene'Fabricant,PE, SE
www.BranchEngineering.com Ronald J. Derrick,PE,GE
TECHNICAL MEMORANDUM
Date: March 31,2011 cLe%.0 PROFFS/
To: Ann M. Batten, P.E.,Region 2 Traffic Analyst; \-\C' I N fe G
David Knitowski,P.E.,Region 2 Access Management Engineer
ct, #62780?E/iiP 9
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From: Damien Gilbert, P.E. /
ORECfON
•Re: Proposed Main Street Mixed-Use Site: �9 ✓D Y 17 I— 2p°y ��
Boyles Property, Champs # 10859; Branch Project No. 09-159 /FN G\\--�
EXPIRES: JUNE 30. 2011
This memorandum is provided as a response to review comments dated December 8,2010 that were
generated by CH2M Hill on behalf of ODOT. The comments were generated in response to a
Transportation Impact Study(TIS), dated October 13,2010,for the subject development and approach
permit application. . ,
It should be noted that there was no requirement for a TIS for this project if no direct access to the state
highway were proposed,but the developer elected to pursue a direct access to Highway 126 in addition to
access to both South 51st Place and South 52nd Street based on the intensity and potential traffic •
generation of the development site. The analysis looked primarily for queuing, level of service and
capacity related impacts to analyze the reasonableness of side street only access to the site in contrast to
State Highway and side street access.
As requested,the primary focus of this response is the primary comment related to simulated
vehicle queuing.
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I. CH2M Hill Primary Review Comment: Validation of the queuing analysis does not appear to
support the need fora Main Street access.
CH2M Hill used the applicant's SYNCHRO and SimTraffic Files to attempt to replicate the
results of the traffic impact study's queuing analysis.Without making any modifications to the
applicant's_files, no substantial queuing issues were observed. After 5 runs of the 2011 and 2016
Build networks without a Main Street driveway,no significant queue buildups were observed on
51st Place or 52nd Street at Main Street. The 95th Percentile queue lengths presented in the
Date Received: 3-11-it
Planner: I Di-co
CIVIL • STRUCTURES TRANSPORTATION GEOTECHNICAL• SURVEYING
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Response to Main Street Mixed Use Site Traffic Study Comments
March 31, 2011
traffic impact study(TIS)at these locations could not be replicated for any of the five runs.
CH2M Hill recognizes that SimTraffic will not produce the same results for each run, but the
large differences between CH2M Hill and the TIS analyses in queue lengths seem to be
unreasonable.
A separate queuing analysis was conducted by CH2M Hill using ODOT recommended
parameters.This analysis concluded that the queues would not be as severe as the TIS queuing
analysis. Adequate storage is available for vehicles leaving the site at the intersections of Main
Street/51 st Place and Main Street/52nd Street without a Main Street driveway access if the
approaches to Main Street are modified from a shared left/right-turn lane to separate left-and
right-turn lanes. This assumes queue storage is provided back to the site access points.
Response: In the ITS on page 27, it reads: "It should be noted that the random number seeding
may not produce identical results each time five runs are averaged. Calculated queue lengths vary
on separate five run averages and depend on the seeding."The ODOT APM requires a minimum
of five runs. The first time the build conditions were simulated in SimTraffic the random seeding
produced a scenario with queue lengths that spilled south from the northbound Main Street/South
51st Place approach past the site driveway, creating a blocking hazard and ultimately stopping
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southbound traffic on South 51st Place, which resulted in queue spill backs toward the highway
when a vehicle needs to enter the site driveway. It was noted that this condition was not replicated
with every five run sequence of simulations,thus the quote above and on page 27 of the TIS. Due
to the nature of the analysis software, the queuing results cannot and will not be replicated.
Therefore alternative analysis methods were explored that can be replicated.
The April 2006 Analysis Procedures Manual(ODOT), Updated 1/2011, provides an alternative
methodology for estimating vehicle queue lengths at unsignalized intersections in Chapter 7,
Intersection Analysis. The passage below is an excerpt from Chapter 7:
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7.12 Methodologies for Unsignalized Movements...
Two-Minute Rule
The Two-Minute Rule is a rule of thumb methodology that estimates queue lengths for major
street left turns and minor street movements by using the queue that would result from a two
minute stoppage of the turning demand volume. This method does not consider the magnitudes
and impacts of the conflicting flows on the size of the queue. The calculation of the 95th percentile
queue using the two-minute rule methodology shall use the following equation:
S= (v) (t) (L) where:
S=the 95th percentile queue storage length (feet)
v =the average left-turn volume arriving in a 2-minute interval
1 =a variable representing the ability to store all vehicles; usually 1.75 to 2.0
(See Exhibit 7-28)
.:;.r.t:,=-. Branch Engineering, Inc.
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` Response to Main Street Mixed Use Site Traffic Study Comments
March 31, 2011
L =average length of the vehicles being stored and the gap between vehicles; 25
ft.for cars. This value can be increased where a significant number of trucks are
present in the turning volume using the same relationship between average
vehicle storage length and percent trucks in turning volumes shown for the
• signalized movement rule of thumb method discussed earlier in this chapter.
Exhibit 7-28 Selection of"t" Values:
Minimum "t":Value Per`eentile-
2.0 98%
1.85 95%
1.75 90%
1.0 50%
Also, a paper"Storage Estimates for Unsignalized Intersections", prepared by TPAU states that:
"The minor right-turn has the same conflict points like the major left turn, so the Two-Minute
•
Rule is(the)most effective methodology to estimate the minor right-turn queue."
(htto://www.oregon.gov/ODOT/TD/TP/docs/TAPM/storageEst.pdf)(the excerpt is above Table 2
. in the paper) .
Using this methodology with the forecasted year 2016 traffic volumes and build conditions with
and without an approach to the state highway, the queues for the forecasted conditions at the
South 51"Place approach to Main Street were recalculated and are provided in the table below
for the northbound left and northbound right approach lanes.
._ _ Intersection Queues S. 51st Place: Two-Minute Rule
Peak Hour Average-- - Average Required
-
Scenario Lane Turn 2-MM Turn Length of Queue Storage
Demand Demand (t)* \'chicle (v*01)
(v) (L) (nearest 25 ft)
951h Percentile Queues
Build Without Left Turn Lane 37 1.233 1.85 25 75
HWY Access Right Turn Lane _ 97 3.233 1.85 25 150**
Build With Left Turn Lane 24 0.80 1.85 25 50
HWY Access Ri•ht Turn Lane 41 1.367 1.85 25 75
. 501h Percentile Queues -.
Build Without Left Turn Lane 37 1.233 1.0 25 50
HWY Access Right Turn Lane 97 3.233 1.0 25 100
Build With Left Turn Lane 24 0.80 1.0 25 25
HWY Access Right Turn Lane . 41 1.367 1.0 25 50
*For 95'i Percentile Queues(t)=1.85.For 50th Percentile Queues(t)=1.0
**Required storage exceeds property frontage on South 51°Place
Branch Engineering, Inc.
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Response to Main Street Mixed Use Site Traffic Study Comments
March 31, 2011
As shown in the table, the calculated required right-turn queue storage length exceeds the
property frontage on South 51'Place using the ODOT approved Two-Minute Rule calculation
method. Previous analyses relied upon SimTraffic to determine that the approach queue was
excessive and concluded that without a direct state highway approach, the queues created a
blocking condition at the site driveway that could be considered an operational hazard. The
reported SimTraffic queue blocking condition was confirmed at the South 51'Place driveway
utilizing the alternative method of analysis. Unfortunately, the randomly seeded SimTraffic
simulation that produced the results was not as replicable as the Two-Minute Rule methodology,
which is listed as an acceptable method for analysis in the Analysis Procedures Manual.
Additional Reasonable Access Information
Additionally, based on other recent permit application meetings with ODOT Access Management Staff, I
have reviewed the potential site generated traffic as it relates to the number of accesses. David
Knitowski,P.E.,ODOT Region 2 Access Management Engineer has indicated in a pre-application
meeting on another project that a measure of reasonable access based on site generated traffic would be
roughly 20 peak hour and/or 200 daily trips per site access. For this site,the potential trip generation was
reported in the TIA to be 251 peak hour trips(see Page 16). The proposed single mid-block, limited-
movement approach to the State Highway supplements the proposed side street accesses, reduces
congestion on local streets,and creates reasonable on-site circulation/access patterns. It also has been
shown to eliminate the operational hazard identified by both ODOT approved queuing analysis methods.
Supplemental Comments Regarding Crash Data
A separate letter was received from David Knitowski, P.E. dated January 31, 2011 discussing criteria for
deviation of approach spacing. There are no known permitted approaches within 990 feet of the proposed
approach, so it is unclear why a deviation would be necessary. The proposed approach has been located
at mid-block, provides reciprocal crossover easements between two properties and is limited to right-
in/right-out movements only. All of these provisions are typically preferred elements for access
management strategies and should be considered an improvement to the highway due to the removal of
left-turning movements. In response to the suggestion that the access must meet deviation criteria,the
following safety factors relevant to this section of Division 51 summarize how those criteria are met:
Roadway Character is not defined in Division 51; however,the character of Main Street is urban and
commercial with many constructed approaches closely spaced along both sides of the street. Direct
Highway access to commercial development is a characteristic of Main Street.
Traffic Character is also not defined in Division 51. The character of traffic on Main Street is generally
urban in nature and includes mostly local trips with residential and commercial origins and destinations.
Test runs down the segment of Main Street have indicated the vast majority of traffic utilizing the
roadway turns onto or off of the street, indicating a commercial and residential access character of traffic.
Branch Engineering, Inc.
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Response to Main Street Mixed Use Site Traffic Study Comments-
March 31, 2011
There is a parallel limited-access State Highway(Eugene-Springfield Highway)with high speeds that
accommodates Highway users through the urban area more efficiently than Main Street.
Geometric Character is not specifically defined in Division 51. Main Street is generally flat in terrain
and straight in alignment in the subject area. Sight distance and turning movements are not restricted by
geometry in the subject location.
Environmental Character is not defined in Division 51. Diluting traffic to include the limited-movement
Highway approach for this site has been shown to reduce queuing and delay,and therefore would reduce
vehicle emissions generated at the approaches which obviously improves air quality and maintains the
local environmental character.
Operational Character is not specifically defined in Division 51. Main Street includes numerous
driveways with left-turn conflicts and inadequate spacing to accommodate left-turn movements. The
proposed access has been designed to optimize operations by prohibiting left-turning movements and
reduce conflicts that are commonly associated with Highway approaches.
There was an uncertified crash summary prepared and submitted by ODOT staff that was proposed as
justification to deny the proposed approach. It is unclear why off-site collisions involving through-
movements, side-swiping/rear-ending of busses, drunk drivers, and distracted pedestrians crossing the
street at night, or speeding motorists losing control and striking fixed objects has anything to do with the
proposed approach. Also, there was a crash illustrated at an existing driveway(MP 5.73)that does not
and has not existed during the analysis period, which raises questions about the accuracy of the summary.
The proposed traffic will be entering the Highway with or without the approach and the conflicts will
occur either at the proposed Highway approach or the existing public street intersections. Furthermore, it
was indicated that there is a SPIS segment abutting the site. This SPIS segment is from MP 5.55 to MP
5.70. It should be noted that the proposed approach is outside of the segment(MP 5.72)and if it is not
permitted, the eastbound right turning movements will be forced to turn off of the highway in the SPIS
segment rather than allowing the traffic to enter and exit the site directly outside of the segment of
concern. It should be noted that the fatality had nothing to do with private driveways, and since that
tragic and unfortunate accident, ODOT has constructed pedestrian crossing safety enhancements and
improved lighting at that location.
Finally,the ODOT scope of work dated December 10, 2009 required 3-years of crash data. It is unclear
why the ODOT summary included crashes from mid-year 2005.
Please see the property owner's legal representative's analysis of the laws associated with reasonable
access and deviation.
Branch Engineering, Inc.
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Response to Main Street Mixed Use Site Traffic Study Comments
March 31, 2011
Conclusion
I trust the above responses adequately address the review comments generated by CH2M Hill on behalf of
ODOT regarding the Main Street Mixed Use Site TIS as well as the supplemental crash summary
submitted by ODOT staff. Reasonable access should not be unreasonably withheld from this property
and as demonstrated by the engineer of record, the property will not have reasonable access without direct
highway access when considering the applicable criteria in ORS 374.310(3).
I look forward to continuing to work toward a reasonable determination that a right-in/right-out highway
approach should be permitted for a development that spans about a full city block and involves relatively
intensive land uses within an urban environment while meeting the intent of access management
standards and allowing this local private economic investment to finally move forward.
Please do not hesitate to contact our office with any questions, or if I can provide any additional
information in response to the non-applicable review comments.
Cc: Jeff Lang, ODOT
John Downing, ODOT
Gerry Juster, P.E., ODOT
Steve Wilson, P.E., ODOT
Nick Boyles, Owner
Steve Hopkins, City of Springfield
Kristen Taylor,TBG Architects& Planners/Inc
Jim Spickerman, Attorney for Applicant
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Branch Engineering, Inc.
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