Traffic Impact Study King Soopers #116 Thornton, Colorado Prepared for: Galloway & Company, Inc.
1.0 EXECUTIVE SUMMARY King Soopers #116, a grocery marketplace anchored commercial development, is proposed to be located on the southwest corner of the 136th Avenue and Quebec Street intersection in Thornton, Colorado. The project includes an approximate 128,000 square foot grocery marketplace, an 18-fueling position gas station, 7,000 square feet of adjacent retail space, and four outparcels. For purposes of this study, it was assumed that the outparcels would develop with three fast food restaurants with drive through totaling 12,000 square feet plus a bank with drive through at 5,000 square feet. Overall it is believed that these assumptions will provide a conservative traffic evaluation. Analysis was completed for build out of the development in 2018 as well as the 2035 long-term horizon to determine intersection and roadway configurations needed at both planning horizons. The purpose of this study is to identify project traffic generation characteristics, to identify potential project traffic related impacts on the local street system, and to develop mitigation measures required for identified impacts. The City of Thornton identified the following key intersections to be included for evaluation within this study: 136th Avenue and Quebec Street 136th Avenue and Newport Street 134th Avenue and Quebec Street The proposed project access intersections along 136th Avenue, Quebec Street, and 134th Avenue were also studied. Regional access to the project site is expected from Interstate 25, Interstate 76, US-85, and E- 470. Primary access to the project will be provided by 136th Avenue and Quebec Street. With the completion of the project, direct access is proposed from a full movement access along 136th Avenue, a three-quarter movement access along Quebec Street, and a full movement access to the south along 134 th Avenue. The full movement access along 136 th Avenue is proposed approximately 630 feet west of the 136 th Avenue and Quebec Street intersection. The three-quarter movement access along Quebec Street is proposed approximately 576 feet south of the 136 th Avenue and Quebec Street intersection. The full movement access along 134 th Avenue will align with the residential street access along the south side of the roadway, which is located approximately 500 feet west of Quebec Street. Kimley-Horn and Associates, Inc. 096083084 King Soopers #116 Page 1
Full build out of King Soopers #116 commercial development on the southwest corner of the 136th Avenue and Quebec Street intersection is expected to generate approximately 12,256 daily weekday driveway trips. Of these, 812 driveway trips are expected to occur during the morning peak hour, while 962 driveway trips are expected during the afternoon peak hour. Distribution of site traffic on the street system was based on the area street characteristics, existing traffic patterns, demographic information, anticipated surrounding development areas, and the proposed access system for the project. Assignment of project traffic was based upon the trip generation described previously and the distributions developed. The traffic assignment was added to the background traffic volumes to determine future traffic with the project. Based on the analysis presented in this report, Kimley-Horn believes the proposed King Soopers #116 project on the southwest corner of 136th Avenue and Quebec Street intersection will be successfully incorporated into the existing and future roadway network. Analysis of the existing street network, the proposed project development, and expected traffic volumes resulted in the following recommendations: 2018 Recommendations The recommended access for the project is to include a full movement driveway along 136 th Avenue, a three quarter movement driveway along Quebec Street, and a full movement driveway along 134 th Avenue. It is important that left turn egress movements are allowed at the 136 th Avenue driveway for exiting project traffic wishing to travel westbound on 136 th Avenue. Without it, exiting project traffic would otherwise likely divert through the Amber Creek residential neighborhood by traveling south to 134 th Avenue, west to Newport Street and then up to 136 th Avenue. With completion of Amber Creek and this King Soopers #116 project, it is believed that 136 th Avenue will be fully constructed as a four lane roadway. This will include the ultimate construction providing two through lane in each direction, eastbound and westbound, along 136 th Avenue. With construction of the project, it is recommended that the 136 th Avenue and Quebec Street intersection be signalized. It is recommended that the left turn movements operate with protected/permitted phasing. Kimley-Horn and Associates, Inc. 096083084 King Soopers #116 Page 2
When the Amber Creek residential neighborhood project constructs Newport Street to intersect with 136 th Avenue, it is recommended that it be constructed with a width sufficient to designate separate northbound left turn and right turn lanes. The northbound left turn lane is recommended to have a length of 150 feet plus 100-foot taper to meet City of Thornton standards. The northbound approach is recommended to operate with stop-control with the installation of a R1-1 STOP sign. In addition, eastbound right turn and westbound left turn lanes of 150 feet in length with 100-foot tapers are expected. 134 th Avenue has been constructed to Quebec Street providing access to the portion of Amber Creek presently being developed. It is recommended that the eastbound approach include separate left turn and right turn lanes, and operate with stop-control. In addition, a northbound left turn lane and southbound right turn lane of 150 feet in length with 100-foot tapers should be constructed along Quebec Street for the roadway intersection. The full movement access intersection along 136 th Avenue is recommended to operate with stop control on the northbound exiting approach. It is recommended that an R1-1 STOP sign be installed for this approach. In addition, separate northbound left turn and right turn lanes are recommended. To improve operations of the northbound left turn exiting movement, an acceleration/refuge lane along 136 th Avenue could be created to allow for a two-stage left turn. Without an access planned along the north side of 136 th Avenue, this will allow the northbound left turn at the T-intersection to operate more efficiently. An eastbound right turn lane of 150 feet with 100-foot taper and a westbound left turn lane of 150 feet with 100-foot taper are also recommended to be constructed along 136 th Avenue for entering traffic. It is recommended that the eastbound exiting approach of the Quebec Street threequarter movement access operate with stop control with the installation of a R1-1 STOP sign. To restrict the proposed access to right turn movements only for exiting traffic, it is recommended that a raised channelizing island be constructed within the driveway throat. In addition, a R3-2 No Left Turn sign is recommended to be placed underneath the STOP sign. Northbound left turn and southbound right turn lanes are Kimley-Horn and Associates, Inc. 096083084 King Soopers #116 Page 3
Based on this, full build out of King Soopers #116 commercial development on the southwest corner of the 136th Avenue and Quebec Street intersection is expected to generate approximately 12,256 daily weekday driveway trips. Of these, 812 driveway trips are expected to occur during the morning peak hour, while 962 driveway trips are expected during the afternoon peak hour. Although the project is a commercial development, pass-by trips were not considered in this analysis. This is due to the relatively low existing traffic volume along 136 th Avenue and Quebec Street. It wouldn t be correct to assume that a large percentage of the passing by traffic (due to the relatively low traffic volume) would be attracted to the site each and every day. Therefore, pass-by trips were not applied in this study to provide an overall conservative analysis. Table 1 summarizes the estimated external traffic generation for proposed development. The trip generation worksheets are included in Appendix C. These calculations illustrate the equations used and directional distribution of trips based on the published ITE Trip Generation Report. Table 1 King Soopers #116 External Project Trip Generation Size (sf) Vehicles Trips Weekday AM Weekday PM Peak Hour Peak Hour Daily In Out Total In Out Total King Soopers Marketplace (813) 128,000 5,034 93 67 160 217 225 442 Drive-In Bank (912) 5,000 406 19 14 33 34 34 68 Fast Food Restaurant w/ DT (934) 12,000 4,492 242 225 467 145 132 277 Gas Station (944) 18 fp 2,012 75 70 145 78 78 156 Specialty Retail (926) 7,000 312 4 3 7 8 11 19 Total Trips 12,256 433 379 812 482 480 962 Kimley-Horn and Associates, Inc. 096083084 King Soopers #116 Page 14
20% [35%] 35% [35%] [30%] 10% 15% 10% 5% 35% [20%] [10%] [20%] 20% [5%] [5%] [20%] 20% [10%] [10%] [15%] 5% [5%] 5% 20%
256(326) 43(48) 417(507) 10(35) 286(357) 195(217) 171(216) 57(72) 111(148) 203(252) 197(57) 108(53) 108(112) 59(85) 451(553) 42(145) 121(180) 107(146) 114(103) 10(36) 417(475) 43(48) 80(114) 165(210) 60(92) 332(391) 133(177) 30(21) 95(120) 108(121) 305(416) 53(44) 57(72) 43(48) 22(81) 10(35) 112(93) 65(128) 360(493) 76(46) 10(35) 30(20) 32(20)
92(152) 345(85) 191(235) 97(123) 202(187) 208(70) 284(354) 130(181) 350(445) 184(257) 216(325) 185(160) 440(518) 595(641) 584(708) 548(646) 506(687) 545(632) 478(576) 430(529) 35(21) 82(49) 11(37) 25(87) 27(19) 9(33) 46(37) 15(51) 103(138) 33(113) 41(91) 16(57) 93(80) 81(62) 114(144) 87(96) 133(168) 152(169) 87(96) 87(96) 76(96) 57(72) 22(24) 40(110) 10(30) 40(25) 60(185)