Appendix C NORTH METRO STATION AREA TRAFFIC IMPACT STATEMENT 88th Avenue Station Prepared for: Regional Transportation Department and URS Corporation as part of the North Metro EIS David Evans and Associates, Inc. 1331 17 th Street, Suite 900 Denver, Colorado 80202 December 2010 88 TH AVENUE STATION TIS December 2010
Table of Contents 1.0 INTRODUCTION... 1 1.1 Existing Conditions...1 1.2 Roadway Network...1 1.3 Existing Traffic Volumes...3 1.4 Proposed Action...5 2.0 TRAFFIC DEMAND... 6 2.1 Background Traffic Volumes...6 2.2 Station-Generated Traffic Volumes...9 2.3 Trip Distribution...9 2.4 Total Traffic Volumes...9 3.0 TRAFFIC OPERATIONS... 12 3.1 No Action Alternative...12 3.2 Preferred Alternative...12 4.0 SUMMARY... 16 88 TH AVENUE STATION TIS December 2010
1.0 Introduction This report documents the potential transportation impacts of the proposed North Metro Corridor Commuter Rail Project in the area of the 88 th Avenue Station and provides technical documentation of the transportation analysis for the North Metro Final Environmental Impact Statement. The general methodology and analysis of other Commuter Rail stations are documented in separate reports. 1.1 EXISTING CONDITIONS The study area for the 88 th Avenue Station is from York Street to Welby Drive, along 88 th Avenue, and from 88 th Avenue to approximately 93 rd Avenue, along Welby Drive. This area primarily consists of residential development, with some industrial and retail uses south of 88 th Avenue. Skyview Academy High School is located north of 88 th Avenue and west of the railroad tracks and Welby Road. There is vacant land northeast of the 88 th Avenue / Welby Road intersection that may be suitable for future Transit-Oriented-Development (TOD). 1.2 ROADWAY NETWORK The existing lane configurations and traffic control at area intersections are shown in Figure 1. 88TH AVENUE 88 th Avenue is a four-lane major arterial within the study area, with a current daily traffic volume of approximately 20,000 vehicles per day (vpd). The existing at-grade railroad crossing is located between closely-spaced signalized intersections at Devonshire Boulevard and Welby Road. 88th Avenue begins at Pecos Street, west of I-25, and terminates at State Highway 2, east of I-76. It is a four-lane major arterial from its western terminus to I-76, except for a 0.6 mile two-lane section east of Dahlia Street. This section will be widened to four-lanes by the end of 2010. DEVONSHIRE BOULEVARD Devonshire Boulevard is a two-lane minor arterial that terminates on its north end at 88 th Avenue. It is the continuation of York Street, which extends north from Denver and connects with SH 224 before bending northeast at about 80 th Avenue and being renamed as Devonshire Boulevard. WELBY ROAD Welby Road is a two-lane minor arterial that terminates on its north end at Thornton Parkway (96 th Avenue). South of 88 th Avenue, Welby Road is a collector that provides access to a mobile home park and industrial development. 88 TH AVENUE STATION TIS C-1 December 2010
Figure 1: Existing Lane Configurations and Traffic Control 88 TH AVENUE STATION TIS C-2 December 2010
YORK STREET Within the study area, York Street is a two-lane collector that provides access to suburban residential development. BEECHWOOD DRIVE AND ASPEN DRIVE Beechwood Drive and Aspen Drive are neighborhood streets that provide access to suburban residential development east of Welby Road. They are located at the north end of the study area with three leg intersections at Welby Road spaced about 250 apart. 1.3 EXISTING TRAFFIC VOLUMES AM and PM peak hour turning movement counts were collected at the following intersections: 88 th Ave / Devonshire Blvd (March 2007) 88 th Ave / Welby Rd (March 2007) 88 th Ave / York St (November 2007) Welby Rd / Beechwood Dr (November 2007) Welby Rd / Aspen Dr (November 2007) Daily roadway counts (March 2007) were also collected at the following locations: 88 th Ave west of Devonshire Blvd 88 th Ave east of Welby Rd Welby Rd north of 88 th Ave The existing traffic volumes collected are shown in Figure 2. 88 TH AVENUE STATION TIS C-3 December 2010
Figure 2: Existing (2007) Traffic Volumes 88 TH AVENUE STATION TIS C-4 December 2010
1.4 PROPOSED ACTION The park-n-ride lot (see Figure 3) would be located west of Welby Road and east of the railroad tracks, starting about 500 feet north of 88 th Avenue and extending north for about 750 feet. By 2020 opening day, it is planned that the north leg of Welby Road would be relocated by others about one quarter mile to the east, in-line with Steele Street. The park-n-ride would have a single access from Welby Road, located about 500 feet south of Beechwood Drive intersection. Departing buses bound for westbound 88 th Avenue would exit the station to the south and access 88 th Avenue at the existing north leg of Welby Drive. A total of 550 parking spaces would be provided by 2020, expanding to a total of 1,500 parking spaces by 2035. Figure 3. Station Area Site Plan 88 TH AVENUE STATION TIS C-5 December 2010
2.0 Traffic Demand 2.1 BACKGROUND TRAFFIC VOLUMES The DRCOG / RTD Regional Travel Demand Model was used to estimate the future traffic volumes near each station area. The methodology is presented in Methodology and Overview. No Action Alternative 2020 and No Action Alternative 2035 traffic volumes are shown in Figures 4 and 5. 88 TH AVENUE STATION TIS C-6 December 2010
Figure 4: No Action Alternative 2020 Traffic Volumes 88 TH AVENUE STATION TIS C-7 December 2010
Figure 5: No Action Alternative 2035 Traffic Volumes 88 TH AVENUE STATION TIS C-8 December 2010
2.2 STATION-GENERATED TRAFFIC VOLUMES Station-generated trips were determined based on the parking supply provided with the proposed station and trip generation rates from existing park-n-rides in the North Metro study area. The base trip generation rate calculations are presented in Methodology and Overview. The established trip generation rate is 0.47 trips per space (80% in / 20% out) during the AM peak hour and 0.45 trips per space (25% in / 75% out) during the PM peak hour. The same trip generation rates were assumed for 2020 and 2035. Table 1 shows the trip generation for the proposed station. Table 1. Station-Related Trip Generation Station Parking AM Peak Hour Trips PM Peak Hour Trips Spaces Inbound Outbound Total Inbound Outbound Total 88 th Avenue (2020) 550 206 51 257 62 185 247 88 th Avenue (2035) 1,500 564 141 705 163 506 669 2.3 TRIP DISTRIBUTION The methodology for determining the trip distribution is presented in Methodology and Overview. The same trip distribution was assumed for 2020 and 2035. Figures 6 and 7 show the trip distribution. For both 2020 and 2035, approximately 65% of the traffic coming from outside the station study area is expected to come in on 88 th Avenue, with about two-thirds of that amount coming from the east. Much of this traffic is expected to come in from the northeast via I-76. The full interchange at I-76 and 88 th Avenue and the relatively short distance (about 2 miles) between Welby Road and I-76 would provide efficient multi-modal travel times to / from the Downtown Denver area. Approximately 10% of the demand is estimated to come in along Welby Road from the north and about 10% is estimated to come in along Devonshire Boulevard from the south. The remaining traffic would access the station via the other study area streets. 2.4 TOTAL TRAFFIC VOLUMES Site traffic associated with the proposed station (from the park-n-ride lot, kiss-n- Ride drop off / pick up facility and bus loops) was added to the No Action Alternative traffic volumes to obtain total Preferred Alternative traffic volumes. Figures 6 and 7 show the total Preferred Alternative traffic volumes for 2020 and 2035, respectively. 88 TH AVENUE STATION TIS C-9 December 2010
Figure 6: Preferred Alternative 2020 Traffic Volumes 88 TH AVENUE STATION TIS C-10 December 2010
Figure 7: Preferred Alternative 2035 Traffic Volumes 88 TH AVENUE STATION TIS C-11 December 2010
3.0 Traffic Operations Delay and Level of Service (LOS) results for the station area intersections are provided in Table 2. 3.1 NO ACTION ALTERNATIVE 2020 It is planned that the north leg of Welby Road would be relocated by others about one quarter mile to the east, in-line with Steele Street. At the 88 th Avenue/Welby Road (north leg) intersection, it is assumed that double eastbound left turn lanes, a corresponding receiving lane on the north leg, a westbound right turn lane and a twolane southbound approach with a shared left / right turn lane and a right turn lane would be constructed as part of the road relocation project by others. See Figure 8 for the No Action Alternative lane configurations and traffic control at area intersections. The highest delays are forecast at the 88 th Avenue/Devonshire Boulevard intersection in the AM peak hour and PM peak hours which are forecast to be LOS C and LOS D, respectively. 2035 There would be no additional network modifications for 2035. The 88 th Avenue / Devonshire Boulevard intersection is forecast to degrade to LOS F in the PM peak hour. All other study area intersections are forecast at LOS C or better. 3.2 PREFERRED ALTERNATIVE 2020 In order to pro-actively address a 2035 traffic issue (see below), the northbound approach at the 88 th Avenue / Devonshire Boulevard intersection would be reconstructed with one northbound right and two northbound left-turn lanes. This is the most effective way to mitigate the projected increase in delay. The start of the taper into the added turn lane would be just north of Devonshire Court and the improvements would be within the existing right-of-way. The station access would function acceptably as an unsignalized intersection. The required mitigation elements for the Preferred Alternative are shown in Figure 9. 2035 Without mitigation, the PM peak hour delay at the 88 th Avenue / Devonshire Boulevard intersection would be projected to increase from 91.9 seconds (LOS F) with the No Action Alternative to 105.1 (LOS F) seconds with the addition of stationrelated traffic. With the three-lane northbound approach that would be part of the Preferred Alternative, the 88 th Avenue / Devonshire Boulevard intersection would be at LOS E during the PM peak hour. The delays would be about 35% less than under the No Action Alternative. To accommodate the approximately three-fold increase in parking supply and increased background traffic, the station access would need signalized with a northbound left turn lane. The required mitigation elements for the Preferred Alternative are shown in Figure 10. 88 TH AVENUE STATION TIS C-12 December 2010
Table 2: Summary of Average Delay and Levels of Service Intersection Signalized Intersections AM Peak Hour 2020 Weekday 2035 Weekday No Action Preferred No Action Preferred LOS Delay LOS Delay LOS Delay LOS Delay 88th / York C 24.2 C 27.3 C 30.1 D 35.9 88th / Devonshire (2020 mitigation) C 27.5 C 24.5 C 34.2 D 44.3 88th / Welby (South Leg) A 4.6 A 4.9 A 7.2 B 10.2 88th / Welby (North Leg) C 22.1 C 25.3 C 27.7 D 42.1 Welby / p-n-r Access (2035 mitigation) - - - - - - C 34.3 Unsignalized Intersections Welby / Beechwood B 13.7 B 14.1 C 15.7 C 17.8 Welby / Aspen B 11.7 B 12.1 B 12.7 B 14.2 Welby / p-n-r Access - - B 14.7 - - - - Intersection PM Peak Hour 2020 Weekday 2035 Weekday No Action Preferred No Action Preferred Signalized Intersections LOS Delay LOS Delay LOS Delay LOS Delay 88th / York B 19.4 C 24.5 C 31.3 D 44.0 88th / Devonshire (2020 mitigation) D 38.1 C 35.0 F 91.9 E 58.2 88th / Welby (South Leg) B 10.7 B 11.0 B 13.6 B 19.3 88th / Welby (North Leg) C 20.9 C 25.2 B 19.1 D 39.1 Welby / p-n-r Access (2035 mitigation) - - - - - - C 26.6 Unsignalized Intersections Welby / Beechwood B 13.1 B 13.5 B 15.0 C 16.2 Welby / Aspen B 13.1 B 13.5 B 14.9 C 16.3 Welby / p-n-r Access - - B 12.5 - - - - Note: LOS for signalized intersections shown for overall intersection. LOS for unsignalized intersections shown for worst-operating movement. Preferred Alternative results reflect roadway and / or intersection improvements where mitigation would be required. 88 TH AVENUE STATION TIS C-13 December 2010
Figure 8: No Action Alternative 2020 and 2035 Lane Configurations and Traffic Control 88 TH AVENUE STATION TIS C-14 December 2010
Figure 9: Preferred Alternative 2020 Traffic Mitigation Figure 10: Preferred Alternative 2035 Traffic Mitigation 88 TH AVENUE STATION TIS C-15 December 2010
4.0 Summary The analysis of the 88 th Avenue Commuter Rail Station for the North Metro Project can be summarized in the following points: The 2035 No Action alternative forecasts operational problems at the 88 th Avenue / Devonshire Boulevard intersection (LOS F) during the PM peak hour. In 2020 there would be approximately 255 trips generated in the AM peak hour and 245 trips in the PM peak hour for the Preferred Alternative. In 2020 there would be approximately 705 trips generated in the AM peak hour and 670 trips in the PM peak hour for the Preferred Alternative. Anticipated impacts due to the new traffic generated by proposed stations would be minor and localized and would be mitigated using standard traffic engineering strategies. The analysis shows that the following mitigation would be required: 88 th Avenue / Devonshire Boulevard: Reconstruct the northbound approach with one northbound right and two northbound left-turn lanes. Start the taper into the added turn lanes just north of Devonshire Court. Improvements would be within the existing right-of-way (2020 opening day). Welby Road / Station Access: Reconstruct with a northbound left-turn lane and signalize the intersection (2035 or sooner, when critical movement becomes LOS F). 88 TH AVENUE STATION TIS C-16 December 2010