Appendix D Traffic Impact Analysis - westplainseis.com

5. TRIP GENERATION and DISTRIBUTION
5.1 Trip Generation and Distribution
PM peak hour trip generation was calculated for each project alternative and phase of development. Trip
generation rates for all land uses except the casino/hotel were based on information published in the
Institute of Transportation Engineers (ITE) 8 th Edition of Trip Generation. The Trip Generation Manual
(TGM) provides empirical data, based upon actual field observations for trip generation characteristics of
similar land uses throughout the United States.
Trip generation for the Casino/Hotel component is based on information provided in Recalibration of
Trip Generation Model for Las Vegas Hotel/Casinos. May, 2002 ITE Journal pp. 26-33. Rowe, Kaseko,
Ackeret. This research indicates that the best predictor of traffic volumes is the size of the gaming
component of casino/hotels as measured by the gaming positions; which provides rates that are inclusive
of the facility, accounting for employees, hotel patrons, and restaurant guests. Trip generation for the
proposed police/fire facility was based on data from Police Station PM Peak Hour Trip Generation in the
Portland Metro Area, December 2, 2009, Portland State University, Armans, Edmonds, et al. Note that
as with site plan Alternative 1 of this project the sites sampled for the above study included a hotel
component and traffic associated with the hotel is captured in the data and included in the trip rate that is
based on the number of gaming positions in the casino component of the development.
For Alternative 3, the trip generation for the central portion of the project was calculated based on the
external restaurant space, the specialty retail area, the hotel and entertainment components (bowling alley
and recreational space). Components within the central building such as the lounge and conference space
were considered incidental and ancillary uses to the primary hotel and entertainment components.
Specific tenants have not been identified for the retail portion of the site. The commercial retail
component located on the west central portion of the site is expected to contain a mix of retailers from
traditional big box stores, to mid-size specialty retailers to smaller retail tenants. Due to the unknown
nature of this retail component, Land Use Category 820, Shopping Center was chosen from the Trip
Generation Manual, 8 th Edition. David Evans & Associates professional experience indicates that the
ITE Shopping Center category provides a sound planning level estimate for larger retail developments
where the specific end user or tenant is unknown. For the retail components contiguous with the
casino/hotel, Land Use Category 814, Specialty Retail was chosen from the Trip Generation Manual, 8 th
Edition.
This report, site plan alternatives and related EIS refer to a ‘Commercial’ portion of the development,
41,633 sf in size and located on the north central part of the site. Specific tenants or uses of this portion
of the development have not been identified. For the purposes of the traffic analysis a medical/dental
usage was assumed and Land Use Category 720, Medical-Dental Office was chosen from the Trip
Generation Manual, 8 th Edition.
Trip generation by alternative and phase are summarized in the following sections.
West Plains Development – Spokane Tribe Page | 44
Traffic Impact Analysis April 28, 2011