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Park West CC(1)-SY 891208 ADDENDUM REPORT ROADWAY SIZING STUDY FOR SOUTHWESTERN BOULEVARD IN COPPELL, TEXAS Prepared for: Prentice Properties Limited, and Santa Fe Pacific Realty Inc. Prepared by: DeShazo, Starek & Tang, 330 Union Station Dallae, Texas (214) 748-6740 J89310 Inc. Dece~:ber 8, 1989 IBTRODUCTION At present the current City of Coppe11 Thoroughfare Plan shows Gateway Blvd. to be constructed as a P6D - a six lane divided principal arterial between Belt Line and Royal. Due to existing capacity constraints which occur within the study area justify this roadway being classified as a four lane divided thoroughfare with intersection widening between Belt Line and Freeport and a four lane undivided section between Royal and Freeport. This study analyzes the capacity differences between the existing Gateway alignment and the proposed Southwestern alignment and then sizes the roadway based upon the year 2010 worst case scenario as outlined in the companion thoroughfare alignment study. The locations of the Prentice Properties and Santa Fe Pacific sites are shown in Figure 1. An overviewof the study corridor indicates capacity constraints which impact the ability to carry through movement through the area. They include the following: The intersection of Cotton Rd. (which is the extension of Southwestern Blvd.) with Royal Ln. The close proximity of this intersection to the diamond interchange of Royal and I.H. 635 limit capacity capabilities of this roadway to turning movements in and out only. The existing design of the Freeport interchange at I.H. 635, a parclo A-B, which has limited capacity capabilities due to the design of the ramps and the difficulty of trucks to negotiate the turns effectively. o The location of North Lake to the east, I.H. 635 to the BETHEL STL & SW RR AIRLINE SOUTHWESTERN BELT UNE FIGURE 1 Proposed Prentl~l Propertl®e end Santa Fe Pacific Realty Developments south, and DFWAirportproperty to the west act as natural barriers to the extension of east/west thoroughfares. o The St. Louis & Southwestern Railroad to the north the major north/south movements in Coppe11 and directs the existing major north/south movements to Denton Tap/Belt Line and MacArthur. Between Royal and Belt Line both alternatives show one continuous east/west roadway south of the RR tracks. The difference between the two alternatives is that the existing Thoroughfare Plan shows a collector which circulates through the sites and ties into Gateway before Royal and Belt Line are reached. The recommended alignment decreases the impact of interior traffic along Southwestern's route and disperses site traffic in an east/west direction to Belt Line south of the Belt Line/Denton Tap intersection and to Freeport south of Grapevine Creek. As the following analysis will show, the recommended alternative reduces the amount of interior site traffic along its route and reduces the impact of site on the heavily utilized Belt Lint/Denton Tap intersection. The following data were generated as part of the alignment study and will be used in this study: BETHEL STL & SW RR NRUNE COWBOY BELT UNE BETHEL /L-Iq 0 0 I~'°° ~' STL & SW RR AJRLINE COWBOY I I, o°° BELT L:NE 8ETHEL STL & SW RR ,'NRUNE BELT LiNE COWBC~¥ BETHEL STL & SW RR CREEK AIRLINE COWBOY BETHEL STL & SW RR NRUNE COWBOy 53-~ BELT UNE BETHEL ,~,(=' STL & SW RR i.£).L .... CREEK ~RLINE COWBOY //?'-t BETHEL STL & SW RR A/RUNE / COWBOy BELT UNE ~ET~EL STL & SW RR joq~ CREEK AJRLINE ls~ BELT UNE COWBOY BETHEL STL & SW RR ViNE CREI cow~o~ H U BETHEL STL & SW RR COW~OY :~ELT L,NE ~U ~ I 7~ The year 2010 24 hour base volumes for the current and recommended alignments are shown in Figures 2 and 3, respectively. The year 2010 pm peak hour base volumes are shown in Figures 4 and 5, respectively. The pm peak hour site traffic are shown in Figures 6 and 7, respectively. The year 2010 pm peak hour base plus site traffic are shown in Figures 8 and 9, respectively. ANALYSIS The roadways of the two alternatives were sized based on the projected year 2010 pm peak hour base plus site traffic in Figures 8 and 9. The results of the roadway sizing analysis is shown in Figures 10 and 11, respectively. The link volume Level of Service criteria based on SDHPT traffic modeling procedures are as follows: Roadway Level Of Service D ~ 4 Lane Divided 2,500 2,920 3,300 3,750 4,150 4 Lene Undivided 1,670 1,940 2,220 2,250 2,780 2 Lane Undivided 830 970 1,110 1,250 1,390 The points where roadway links lose capacity are at the intersections. Proper lane geometry at the intersections provide significant capacity enhancements where there are predicted high turning volumes. An estimate of the future geometry of the Belt Line/ Denton Tap and Freeport/South- western intersections are shown in Figures 12 and 13, respectively. Despite being four lanes divided between Freeport and Belt Line, Southwestern will likely be six lanes divided at Belt Line and five lanes divided or more at Freeport. West of Freeport, Southwestern should be four lanes undivided, flaring out to six lanes divided at the Freeport intersection. CONCLUSION By utilizing existing counts, SDHPT and NCTCOG Year 2010 projections and the City Of Coppell Thoroughfare Plan, the area 2010 base conditions have been estimated. Over 500 acres of warehouse/office development have been added over and above the year 2010 base conditions to reflect a worst case scenario. The resulting link volumes were analyzed to determine the size of each thoroughfare. This study shows that the recommended route of Southwestern Blvd. will operate at Level of Service "A" as a four lane divided roadway between Belt Line end Freeport and as a four lane undivided roadway between Royal and Freeport. The Thoroughfare Plan~s aligllment of Gateway would also opreate at Level of Service "A" as a four lane divided roadway between Belt Line and Freeport and as a four lane undivided roadway between Royal and Freeport. Therefore, regardless of which alignment, Southwestern/Gateway worst case volumes do not justify a six lane divided roadway.