march 8, 2007 - granicus

FILENAME: H:\PROJFILE\SIGNAL HILL COSTCO GAS\SIGNAL HILL COSTCO GASOLINE ADDITION.DOCX

MEMORANDUM

Date: May 23, 2013 Project #: I-10

To: Jennifer Murillo, Costco Wholesale

Terry Odle, Mulvanny G2 Architecture

From: Sonia Hennum, PTOE

Project: Signal Hill Costco Gasoline Addition

Subject: Costco Gasoline Fuel Station Transportation Characteristics

As requested, Kittelson & Associates, Inc. (KAI) has reviewed the site layout, on‐site circulation, and

traffic characteristics for the proposed Costco Gasoline fuel station addition to the existing Costco

warehouse in Signal Hill, California. The proposed site plan for the Signal Hill Costco Gasoline addition

is provided in Figure 1.

KAI has worked with Costco and the development team to assist with transportation issues, on‐site

circulation, and on-site operational needs as they relate to the proposed fuel station’s design. As part

of this work, KAI reviewed the proposed site plan for the location, circulation pattern, operations, and

access to the fuel station. KAI works with Costco on site development projects throughout the United

States and Canada, with a large majority of these projects focused in California. From all of this work,

we are able to provide a breadth of understanding and information related to the circulation and

operational needs of Costco Gasoline fuel stations and their interaction with Costco warehouses.

COSTCO GASOLINE CHARACTERISTICS

Costco Gasoline fuel stations function as ancillary uses to the Costco warehouse that shares their site.

Typical operating hours for Costco Gasoline facilities are approximately from 6:00 a.m. to 10:00 p.m.

on weekdays and 7:00 a.m. to 9:00 p.m. on weekends. The fuel station will be closed on holidays

when the warehouse is also closed. The fuel station will only be available for Costco members and will

require a Costco membership card to activate the pumps for dispensing gasoline. Payment can only

be made with credit or debit card and, unlike traditional gas/service station operations, there are no

other automotive services (such as repairs or maintenance) or other type of sales (including

food or sundries) associated with the Costco Gasoline facility.

Exhibit A

Signal Hill Costco Gasoline Addition Project #: I-10 May 23, 2013

Kittelson & Associates, Inc. Boise, Idaho

All Costco Gasoline facilities have a minimum of one attendant working at the gas station when it is

open who is responsible for expediting members’ use of the fuel pumps, directing entering vehicles to

open pump locations, and managing on-site queues from the pumps. A key consideration in the

review of Costco Gasoline fuel stations is their function as an ancillary use for the Costco warehouse.

Costco has invested significant resources into identifying the travel characteristics of their members

to ensure site planning and development work is based upon the best possible data. Travel associated

with Costco warehouses and fuel stations displays unique characteristics due to membership

requirements and the nature of Costco sales (typically larger volume purchases and lower frequency

visits than traditional retailers). These unique elements apply to the trip generation for Costco

warehouses, Costco fuel stations, and the interaction of trips between the two.

A key finding from the studies conducted at Costco facilities is that, while they can be busy during

peak periods, the fuel stations themselves don’t generate a significant number of new trips on their

own since the station is an ancillary use to the warehouse. A significant proportion of the trips to and

from Costco fuel stations are internal capture trips. Internal capture trips are those customers who

patronize both the warehouse and the gasoline pumps during a single visit to the site. As such,

although they account for a trip to both the warehouse and the fuel station, they only account for

one overall vehicle trip to the site and on the surrounding transportation system. These fuel station

trips are vehicles that are already coming to the site to shop at the existing Costco warehouse today

but who, in the future, will also make a stop to purchase fuel. At some existing sites the proportion of

these internal trips ranges as high as 75% (i.e., 75% of the vehicles using the fuel station are also

shopping at the warehouse as their primary destination on site). The overall result of this travel

characteristic is that the addition of a fuel station to an established existing Costco warehouse

has a much smaller effect on increasing traffic to the site, traffic congestion on the site, and on the

surrounding roadways than is commonly assumed.

TRIP GENERATION ESTIMATE

KAI maintains a database of traffic data and transportation characteristics for Costco Wholesale. The

database contains transportation information such as trip generation, trip type percentages, and

parking demand for Costco locations in the United States, Canada, and Mexico. The database is

updated and refined each time new Costco traffic counts or information become available to KAI. The

Costco database was determined as the best source from which to develop the trip generation

estimate for the Signal Hill Costco Gasoline addition project since it provides use-specific data that

most accurately represents the anticipated traffic characteristics of the project.



Trip Count Information

The database currently has traffic information from numerous locations in large metropolitan areas

of California (Bay Area, LA Area, and San Diego). Twenty-three sites were selected from the database

in the development of the trip generation estimate for Signal Hill for a variety of reasons such as

warehouse sales volume, fuel station size, and similar geographic market area and membership base.

Table 1 summarizes the characteristics of the representative sites and their respective peak hour trip

generation (rounded to the nearest five vehicles per hour).

Table 1 Trip Generation Characteristics of Representative Costco Gasoline Sites

Location Fuel Station Size

(fueling positions) Weekday PM Peak Hour

Total Trip Ends Weekend Midday Peak Hour

Total Trip Ends

Antioch, CA 16 N/A 380

Burbank, CA 16 416 468

Carlsbad, CA 16 440 N/A

City of Industry, CA 16 466 476

Fountain Valley, CA 16 467 464

Garden Grove, CA 16 N/A 442

Laguna Nigel HR, CA 16 N/A 502

Laguna Nigel, CA 16 N/A 440

Morena Blvd, CA 16 372 N/A

Oxnard, CA 16 392 410

Rancho Del Ray, CA 16 414 N/A

S San Diego, CA 16 362 N/A

Simi Valley, CA 16 414 392

Vallejo, CA 16 N/A 440

Woodinville, WA 16 416 N/A

Aurora Village, WA 16 414 N/A

Santa Clara, CA 12 378 386

El Camino, CA 16 500 516

NE San Jose, CA 16 474 494

San Jose II, CA 16 430 466

Scottsdale, AZ 20 500 570

Tucson, AZ 20 340 440

Issaquah, WA 20 490 600

Average 430 460

An important trend seen from trip generation studies at these Costco Gasoline facilities is that trip

generation is not necessarily directly related to the number of islands (or fueling positions) at a

facility. Although the standard reference manual ITE Trip Generation currently reports trip generation

for gasoline stations based on the independent variable of fueling positions, more recent

transportation studies indicate that other variables besides the specific number of fueling pumps

have a much larger influence on trip generation. As such, the profession is moving towards modifying

this for the gasoline station land use codes and working on studies that include different independent

variables. An ITE paper was just recently published in the June 2011 ITE Journal documenting a study



completed by North Carolina State University confirming these methodologies. In particular for

Costco Gasoline facilities, membership base (since they are member-only facilities), market area, and

adjacent warehouse activity appear to have a much greater influence on the activity levels of the

associated fuel stations than whether the facility is 12, 16, or 20 fueling positions (the three typical

Costco models). As such, actual trip counts (as opposed to a trip rate per fueling positions) were used

in developing an estimate for the Signal Hill Costco Gasoline addition.

Trip Type Information

In addition to traffic counts, it is also important to quantify trip type information when evaluating the

characteristics of the fuel station traffic. The Costco database contains member survey information

from multiple sites to establish specific trip type characteristics for the fuel station. The surveys were

created and administered consistent with the Institute of Transportation Engineers (ITE) Trip

Generation reference guidelines and documented four different trip types for the fuel station traffic:

net new trips, internal trip, pass-by trips, and diverted trips. The documented fuel station trip type

information for Costco Gasoline stations is summarized in Table 2.

Table 2 Costco Gasoline Trip Type Characteristics

Trip Type Weekday PM Peak Hour Weekend Midday Peak Hour

Internal Trips 34% 35%

Pass-by/Diverted Trips 49% 45%

Primary Trips 17% 20%

Internal trips account for those members who patronize both the warehouse and the gasoline pumps

during a single visit to the Costco site. As such, although they account for a trip to both the

warehouse and the fuel station, they only account for one vehicle trip to the site and on the

surrounding transportation system. Based on studies including surveys at Costco Gasoline stations

and membership card transaction data, on average 34% of the members buying gas during the

weekday p.m. peak hour and 35% of the members buying gas during the weekend midday peak hour

are members whose main purpose to the site is to visit the Costco warehouse and who can be

classified as an internal trip.

Pass-by trips represent members (and trips) that are currently traveling on the surrounding street

network for some other primary purpose (such as a trip from work to home) and stop into the site en

route during their normal travel. As such, pass-by trips do not result in a net increase in traffic on the

surrounding transportation system and, typically, their only effect occurs at the immediate

intersections and site access driveways where they become turning movements. Diverted trips are

similar to pass-by trips in that they are trips already on the surrounding transportation system and

they stop into the site during their course of travel. They differ from pass-by trips in that they would



not be on the roadways immediately adjacent to the site during their normal travel and, therefore,

have to divert from a roadway further away to travel to the site. Although they may be a new trip on

the roadways immediately adjacent to the site, they are not a new trip on the overall transportation

system. Based on studies using surveys at Costco Gasoline fuel stations, on average 49% of the

weekday p.m. peak hour trips and 45% of the weekend midday peak hour trips at Costco Gasoline

fuel station can be classified as either pass-by or diverted trips. The breakdown between pass-by and

diverted trips is dependent on the site location and surrounding transportation system.

The combination of these trip types results in the fact that only approximately 20% of the peak hour

trips to the Costco Gasoline fuel station can be considered actual net new trips on the overall

transportation system.

Resultant Trip Generation Estimate

Taking the conservative average trip count of the two highest trip-generating locations (which also

happen to be 5 island facilities – Scottsdale and Issaquah) and combining that with the trip type

characteristics seen at Costco Gasoline fuel station results in the overall trip generation estimate for

the Norwalk Costco Gasoline facility as summarized in Table 3.

Table 3 Costco Gasoline Trip Generation Estimate

Weekday PM Peak Hour

Trip Ends Weekend Midday Peak Hour

Trip Ends

In Out Total In Out Total

Total Trips 215 215 430 230 230 460

Internal Trips (34%, 35%) (70) (70) (140) (80) (80) (160)

Pass-by/Diverted Trips (49%, 45%) 105 105 210 100 100 200

Net New Trips 40 40 80 50 50 100

*Percent of external trips

As can be seen from Table 3, the proposed Signal Hill Costco Gasoline fuel station is estimated to

generate approximately 80 net new vehicle trips (or 40 vehicles) during the weekday p.m. peak hour

and approximately 100 net new vehicle trips (or 50 vehicles) during the weekend midday peak hour.



SITE CIRCULATION & QUEUING

The proposed site plan has been developed to optimize traffic circulation to and within the site and to

minimize impacts to existing operations within the center and on E Willow Street. Costco has

incorporated the following design features into the fuel station to provide efficient circulation:

The fuel station is one-way directional flow only (in this case from the west to the east)

which simplifies vehicle paths and minimizes conflict points and congestion

There is a pass-through lane provided on each side of each island to allow vehicles at the

second pump to pull around vehicles at the first pump in front of them without having to

wait for that vehicle to finish their purchase before both vehicles can clear the area

The pass through lane also allows vehicles waiting in queue to pull around a vehicle in

front of them at the second pump and up to the first pump without having to wait for that

vehicle to clear

KAI also evaluated the anticipated vehicle queuing at the proposed fuel station. The purpose of this

evaluation was to ensure the site plan provides sufficient storage to accommodate the anticipated

peak period queues within the fuel station area so they do not spill back or impact circulation

elsewhere within the retail center parking field. KAI collected vehicle queue information and traffic

counts from other existing Costco Gasoline sites with activity similar to that expected at the proposed

Signal Hill location. Data was collected during the Saturday midday which is the known busiest time

period for Costco Gasoline fuel station operations. Data was collected from 11:00 a.m. to 3:00 p.m. at

the following locations:

Antioch, California

Vallejo, California

Scottsdale, Arizona

Issaquah, Washington

The observed queue lengths every 30 seconds during the weekend peak time period were

documented for all four locations. From this data, average, 95th percentile, and maximum queues

were calculated for the peak hours. The results are summarized in Table 4.

Table 4 Costco Gasoline Saturday Peak Vehicle Queues

Peak Period Vehicle Queues*

Location Average 95th

Percentile Maximum Observed

Antioch, CA 5 10 15

Vallejo, CA 15 20 30

Scottsdale, AZ 37 42 44

Issaquah, WA 12 27 37

*Queues report are the total number of vehicles waiting behind the fuel pumps (not including those at the pumps themselves)



Table 4 shows that the maximum queue observed behind the pumps at any of the four sites was 44

vehicles at the Scottsdale location. The largest 95th percentile queue observed was 42 vehicles. This

means that for 95% of the peak period, the queues at all four locations were less than 42 vehicles. At

three of the locations, the 95th percentile queue was significantly less than 30 total vehicles. Figure 2

provides a graphic that shows the maximum queue length observed at any of the four locations (44

vehicles) overlaid on the proposed Signal Hill site plan. As can been seen from the figure, the

maximum expected queue will be able to be contained within the fuel station area without any spill

back or interference with other areas within the retail center parking. During all other time periods,

the queuing at the fuel station will be less than shown in the figure. Based on the data collected from

the four comparable sites, the maximum predicted queue length will be contained well within the

queuing area of the fuel station and will not impede acceptable traffic flow or circulation within the

existing site. Finally, as outlined previously, there will be a minimum of one trained attendant working

at the gas station at all times when it is open who is responsible for expediting members’ use of the

fuel pumps, directing entering vehicles to open pump locations, and managing on-site queues from

the pumps.

We trust this memorandum provides the information requested at this time related to our work with

the site planning for the proposed Costco Gasoline fuel station addition in Signal Hill, California. We

will continue to work with the development team on both on and off-site transportation issues as the

project moves forward. If you have any question about this summary, or if you require additional

information, please contact us at 208.338.2683 or [email protected].

mailto:[email protected]

march 8, 2007 - granicus

Documents