Traffic Report Scoping and Assumptions (Signed)
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March 21, 2022
Tracy Bono, PE City Engineer City of Ammon
2135 South Ammon Road
Ammon, Idaho 83406 Dear Tracy,
Anderson Wahlen & Associates appreciates the opportunity to submit a scope and the associated
overall assumptions for a traffic study for the Riviera Park mixed use development to be located on the northeast corner of Lincoln Road and 25th East. Attached is a site plan that shows proposed access locations and land uses. This letter will establish an acceptable scope/overall assumptions so that AWA and the City of Ammon has agreeable parameters to complete the
study.
Trips are such that a Category II TIS is planned in compliance with the BMPO Asset Management Plan. With this, future traffic will be evaluated for five and ten years after the site opening. Also attached is a PM Peak trip generation worksheet that shows total, internal, net-new
and pass-by trips for the site. It also shows preliminary trip distribution assumptions and
projections for net-new trips through key intersections to the north, east and west. The intersections and origin/destination assumptions are preliminary. They are different than the assumptions from the recently completed Costco Traffic Impact Study because some of this development is less regional in nature. Specifically, the new development has a lot of land uses
that will attract more trips from the homes to the east and this was adjusted from the Costco Study. To keep the preliminary trip distribution simple, 25 percent of net-new trips were assumed to travel equally to the east, west, north and south. Based on the trip generation and trip distribution, the following scope for the traffic study is proposed:
• Data Collection – PM peak (Friday) and Saturday Mid-day period traffic counts at following intersections: o Lincoln Road and 25th East o Lincoln Road and Woodruff Avenue
o Lincoln Road and Ammon Road
o 25th East and Iona Road
o Costco Accesses to 25th East The trip distribution assumptions show that these intersections will be impacted. Traffic is
expected to have more roadways to distribute after these intersections. Therefore, it is not
necessary to count or address other intersections. Based on the 25 percent origin/destination assumption to each direction and if 15 percent continues through each intersection with 5 percent
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turning right and 5 percent turning left, the following volumes were projected for the three major
offsite intersections to be counted/analyzed: Major Intersections to east, west and north of project Inbound Outbound
Major Street Through Movements (15% of net-new trips) 105 89
Turning Movements Left (5% of net-new trips) 35 30 Right (5% of net-new trips) 35 30
Please confirm that these are acceptable assumptions as we would like to start counting traffic in
the area in the next few weeks. Sincerely,
Shaun Young, PE Anderson Wahlen & Associates
Building NumberFacilityITE Land UseArea 1,000 sf / UnitsWeekday Trip RateGenerated TripsInternal Trip %External TripsPass-by %Pass-by TripsPrimary TripsPM In % PM Out %Pass-by Inbound TripsPass-by Outbound TripsNet-New Inbound TripsNet-New Outbound TripsTotal Inbound TripsTotal Outbound Trips1 Credit Union 912 3.020.45 62 20%5047%24 2650% 50%12 12 13 13 25 252 Retail 820 7.43.81 29 20%2434%91548% 52%457811133 Restaurant - Fast w/ Drive 934 6.032.67 197 20%15850%79 7952% 48%41 38 41 38 82 764 Restaurant - Dine In 930 7.814.13 111 20%890%08955% 45%0 0 49 40 49 405 Restaurant - Fast w/ Drive 934 3.032.67 99 20%8050%40 4052% 48%21 19 21 19 42 386 Restaurant - Fast w/ Drive 934 6.032.67 197 20%15850%79 7952% 48%41 38 41 38 82 767 Restaurant - Fast w/ Drive 934 6.032.67 197 20%15850%79 7952% 48%41 38 41 38 82 768 Credit Union 912 4.020.45 82 20%6647%32 3450% 50%16 16 17 17 33 339 Club 925 4.511.36 52 20%420%04266% 34%0 0 28 14 28 1410 Restaurant - Fast w/ Drive 934 5.232.67 170 20%13650%68 6852% 48%35 33 35 33 70 6611 Grocery Store 850 58.99.24 545 20%43636%157 27951% 49%80 77 142 137 222 21412 Retail - Large 862 30.02.33 70 20%5648%27 2949% 51%13 14 14 15 27 2913 Entertainment Center 495 45.02.31 104 20%840%08447% 53%0 0 39 45 39 4514 Restaurant - Fast w/ Drive 934 6.032.67 197 20%15850%79 7952% 48%41 38 41 38 82 7615 Apartment 221 35.00.44 16 20%130%01361% 39%00858516 Apartment 221 35.00.44 16 20%130%01361% 39%00858517 Apartment 221 35.00.44 16 20%130%01361% 39%00858518 Apartment 221 35.00.44 16 20%130%01361% 39%00858519 Apartment 221 35.00.44 16 20%130%01361% 39%00858520 Apartment 221 35.00.44 16 20%130%01361% 39%00858521 Apartment 221 35.00.44 16 20%130%01361% 39%00858522 Apartment 221 35.00.44 16 20%130%01361% 39%00858523 Apartment 221 35.00.44 16 20%130%01361% 39%00858524 Apartment 221 35.00.44 16 20%130%01361% 39%00858525 Town Homes 210 172.00.99 171 20%1370%0 13763% 37%0 0 86 51 86 51Total 1,962 673 1,289 345 328 695 594 1040 922 1,962 1,962 196215% of Net-New 104.25 89.10 5% of Net-New 34.75 29.70 Weekday PM Peak Hour