South Capitol Street Trail Draft Concept Plan Chapter 4, pages 20-34

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Trail overview and concepT areas

The following section describes the detailed improvement recommendations and design considerations for locations along the trail. Based on the varying nature of the corridor and implementation considerations, this information is organized into the following project concept areas :

CONCEPT AREA A: DC Village, Laboratory Rd, and Overlook Ave

CONCEPT AREA B: Defense Blvd , Overlook Ave, and South Capitol St

CONCEPT AREA C: South Capitol St, MacDill Blvd/Malcolm X Ave

CONCEPT AREA D: South Capitol St, Firth Sterling Ave, and Defense Blvd

PAGE

CONCEPT AREA A

Pinch Point 1 .................................................................................................... 23

CONCEPT AREA B

Pinch Points 2, 3.1, 3.2, 3.3, 4 .........................................................................27

CONCEPT AREA C

Pinch Points 5, 6, 7 .......................................................................................... 39

CONCEPT AREA D

Pinch Point 8 .................................................................................................... 45

TRAIL CONCEPT AREAS ANDPINCH POINTS

pinch poinTs overview

In general terms, the preferred dimensions for a trail adjacent to a roadway are a 10-foot trail, with a 5-foot separation and 2-foot buffer. Trail separation is defined as the distance from the edge of a roadway towards the trail, and a trail buffer is the distance from the edge of a trail towards an outside obstruction. Additional separation and buffer distances are recommended where feasible. As previously mentioned, in some locations trail widths and buffers will have to be reduced to navigate pinch points.

The pinch points are located in the following concept areas and illustrated on the graphics on the following pages:

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concepT area a concepT area B

concepT area c concepT area d

concepT area and pinch poinT locaTions

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(this page was left blank intentionally)

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c o n c e p T p l a n a r e a a

Concept Area A includes DC Village and segments of the trail along Overlook Ave from Laboratory Road to south of Magazine Road/ Chesapeake Street.

The DC Village area is located east of I-295 and is bounded on the north by the Bellevue residential neighborhood and on the south by Oxon Cove and NPS parklands. DC Village is an area slated for redevelopment and currently the existing street and sidewalk networks are in extreme disrepair and are non-contiguous. An existing asphalt trail at the eastern terminus of DC Village Lane leads to a bridge over Oxon Run and the NPS trail along the south side of Oxon Cove.

In general, there is very limited existing information about the DC Village area, which is owned by the District of Columbia. The future development of DC Village as defined by the DC Village Master Plan indicates a rework of road and pedestrian pathways. Progress with the redevelopment project is still ongoing at the time of this report, and the future trail alignment within this segment will be refined once the redevelopment proceeds further. Excerpts of the DC Village Master Plan are provided in Chapter 2 of this plan.

The preliminary trail alignment within this segment consists of a 10-foot sidepath extending from the existing connection to DC Village Lane, along DC Village Lane and Blue Plains Drive to Shepherd Parkway. The trail extends along Shepherd Parkway north to the intersection of Laboratory Road, where it connects to Overlook Avenue.

Along Overlook Avenue segment, I-295 runs parallel along the eastern boundary and the Blue Plains DC Water and Sewer Authority (DCWASA) facility, Bolling Air Force Base, and Anacostia Naval Station are situated along the western boundary. Overlook Avenue extends north to Magazine Drive and eventually to Malcolm X Avenue, where it connects to South Capitol Street. A plan of Concept Area A is provided in the following pages.

Pinch point 1 is located within Concept Plan Area A

Pinch Point 1 – Approximately 400-feet north of Overlook Avenue and Laboratory Road/ I-295 northbound off-ramp to Shepherd Parkway a 7-foot wide pinch point is created for 400-feet by bus stops on either side of the road, and the military base wall adjacent to the roadway. Within this area there is also a driveway entrance approximately 150-feet north of the intersection. At this location there currently is a 4-foot sidewalk which would be replaced with the proposed trail. In order to avoid this pinch point, it is recommended that the trail extend north along the east side of Overlook Avenue to a mid-block crossing north of the intersection. The proposed alignment would provide a 10-foot-wide trail in this pinch point area. (A graphic of pinch point 1 is provided in the following pages, as well as an excerpt from the traffic study.) Alternative A is recommended.

Pinch point 1 - View East along Overlook Ave Source: TDG Library

concepT area a

overview

Recommended Cross Section with Trail in DC Village

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pinch poinT 1 Traffic analysis

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The following section discusses each pinch points and alternative analysis results based on potential mitigation measures, and Table 11 summarizes the comparison of the future no-build and build alternative analysis results at the pinch points. Table 11. Summary of Future No-build and Build Alternative Analysis Results – Pinch Points

Pinch Point

No-Build Conditions Build Conditions-Alternative A Build Conditions-Alternative B Delay

(sec/veh) V/C Ratio

or LOS

Delay (sec/veh)

V/C Ratio or

LOS

Delay (sec/veh)

V/C Ratio or

LOS or Speed

(mph) Density

(pc/mi/ln) or Speed

(mph) Density

(pc/mi/ln) or Speed

(mph) Density

(pc/mi/ln)

1 13.8 (21.1) 0.48 (0.70) B (C) Same as future no-build 13.7 (21.1) 0.49 (0.71) B ( C )

2 13.8 (15.5) 0.39 (0.47) B (B) 17.3 (18.0) 0.54 (0.68) B ( B ) Same as future no-build

3

3.1 10.8 (14.8) 0.45 (0.76) B (B) 10.7 (13.3) 0.45 (0.76) B ( B ) Same as future no-build

3.2 13.8 (15.5) 0.39 (0.47) B (B) 17.3 (18.0) 0.54 (0.68) B ( B ) Same as future no-build

3.3 47.4 (46.1) 9.0 (13.0) A (B) Same as future no-build Same as future no-build

4 46.8 (44.8) 6.4 (10.1) A (F) 46.8 (44.8) 6.4 (10.1) A (F) Same as future no-build

5 30.7 (14.0) 0.98 (0.55) C (B) 54.3 (17.8) 1.06 (0.69) D ( B ) Same as future no-build

6 30.7 (14.0) 0.98 (0.55) C (B) Same as future no-build 54.3 (17.8) 1.06 (0.69) D ( B )

7 42.3 (42.2) -- B (B) 41.3 (41.1) -- C ( C ) Same as future no-build

8 24.7 (25.8) 0.72 (0.69) C (C) 26.2 (25.9) 0.73 (0.69) C ( C ) 26.2 (25.9) 0.73 (0.69) C ( C )

Pinch Point #1 (Overlook Avenue & Laboratory Road) Pinch point 1 is at the intersection of Overlook Avenue and Laboratory Road. Alternative A at this location proposes to retain the existing configuration. Alternative B at this location includes eliminating one (1) northbound through lane, and changing it to one through lane with shared left and right turns; and reducing the width of southbound through lane with shared right turn from 12’ to 11’. The lane configuration for the proposed alternative is illustrated in Figure 4. Intersection capacity analysis was performed for the proposed alternative, using the HCM methodology. The results of the alternative analysis for both AM and PM peak hours are summarized in Table 12.


Figure 4. Lane Configuration Diagram for Proposed Alternative for Pinch Point #1

Table 12. Comparison of Existing and Alternative Capacity Analysis at Pinch Point #1 [Overlook Avenue and Laboratory Road] AM (PM)

The results of the capacity analysis for this proposed alternative indicate that the intersection of Overlook Avenue and Laboratory Road will continue to operate at a Level of Service C or better during both AM and PM peak hours. Pinch Point #2 (Overlook Avenue & Defense Boulevard) The next identified pinch point is the intersection of Overlook Avenue and Defense Boulevard. Proposed measures for Alternative A at this intersection includes eliminating one (1) southbound through lane, and reducing the storage length for southbound right-turn lane at the intersection of Overlook Avenue and Magazine Road. The lane configuration for the proposed alternative is illustrated in Figure 5. Intersection capacity analysis was performed for the proposed alternative, using the HCM methodology. The results of the capacity analysis for this alternative indicate that the intersection of Overlook Avenue and Defense Boulevard will continue to operate at a Level of Service B for both AM and PM peak hours with a slightly increased delay of 15.4 sec/veh and 17.1 sec/veh during AM and PM peak hours, respectively. Alternative B consists of retaining the existing configuration, thus no further traffic analysis was performed for this alternative. The results of the alternative analyses are summarized in Table 13.

Condition Control Delay

(sec/veh) v/c Ratio

Level of Service

Existing Signal 13.4 (20.9) 0.47 (0.65) B (C)

Alternative A – retain existing configuration Same as existing configuration

Alternative B – retain existing configuration and eliminate one northbound thru lane on Overlook Avenue

Signal 13.0 (21.3) 0.47 (0.66) B (C)

(For full report, refer to Appendix B)

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concepT plan area a - overview pinch point 1

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pinch poinT 1 - laBoraTory rd concept plAn AreA A

**Roadway/ trail geometrics, and traffic control measures are to be furtherrefined during final design.**

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c o n c e p T p l a n a r e a B

Concept Plan Area B includes trail segments along Overlook Avenue from south of Defense Boulevard to north of Overlook Avenue / South Capitol Street split.

Along the South Capitol Street and Overlook Avenue segment, I-295 runs parallel along the eastern boundary and Bolling Air Force Base, and Anacostia Naval Station are situated along the western boundary. Overlook Avenue extends north, where the roadway merges with South Capitol Street, which is a major thoroughfare extending through the southeast quadrant of the District of Columbia from the U.S. Capitol to the District/ Maryland State line. This route connects the eastern shore of the Anacostia River to the rest of the city. Along the Overlook Avenue/ South Capitol Street corridor, the trail is proposed along the western side of the roadway corridor beyond the Laboratory Road intersection, and eventually continues north to the Malcolm X Ave. intersection. Along the trail corridor, the trail is bordered by the roadway section, and several security walls along the military base property which creates a series of “pinch-points” for the trail. Additional constraints at each location may include utilities, drainage structures, traffic control devices and signage, environmental constraints and right-of-way/property limits.

As previously mentioned, the minimum desirable width for the proposed trail is 10-feet, with a 2-foot buffer and 5-foot separation from an adjacent roadway. In constrained areas throughout the trail corridor, 8-feet is recommended for the trail, with a 1-foot buffer and 1-foot separation. An absolute minimum width for limited trail segments is a 6-foot width with no buffer or separation. Where feasible, additional separation and buffer distances are highly recommended.

Concept Area B is illustrated in the following pages.

Also provided are excerpts from the traffic study. Traffic comparisons are based on existing volumes. Analysis with future volumes are provided in Appendicies A & B, and show no appreciable difference to existing results.

Pinch points 2, 3 and 4 are included within Concept Plan Area B.

Pinch Point 2 – Approximately 200 feet North of Magazine Road/Chesapeake St. intersection and south of Overlook Ave/Defense Boulevard (S) intersection. This 200-foot stretch of 9-foot wide pinch point area is created as a result of the minimal space between the military base walls and the roadway. The proposed measures to extend the trail through this pinch point is to reduce the Overlook Ave travelway to two 11-foot travel lanes with a 10-foot trail, 8-foot separation, and 3-foot buffer. (Traffic study alternative ‘A’ is recommended). These improvements would provide an approximately 21-foot wide area for the trail segment. An alternative and absolute minimum consideration at this location would be to retain the three 11-foot lanes with a 6-foot trail, 4-foot separation, and a 2-foot buffer.(A graphic of pinch point 2 is provided in the following pages)

Pinch point 3.1 - View South along Overlook Ave Source: TDG Library

concepT area B

overview

Pinch point 3.2 - View North along Overlook AveSource: TDG Library

Pinch Point 3 – From Overlook Ave/ Defense Boulevard (S) intersection, north to Overlook Ave/South Capitol Street diverge gore. This pinch point is separated into three segments, pinch points 3.1 through 3.3.

Pinch point 2 - View South along Overlook Ave Source: TDG Library

Pinch point 3 - View North along Overlook Ave Source: TDG Library

Pinch Point 3.1 extends for 800 feet from the Overlook Ave/ Defense Boulevard (S) intersection north 300 feet where the military base walls and roadway pinch to 12 feet. Within this pinch-point it is proposed that Overlook Avenue be reduced to two 11-foot lanes with a 10-foot trail, 10-foot separation, and a 3-foot buffer. (Traffic study alternative ‘A’ is recommended). The improvements would provide 23 feet for the trail, separation and potential stormwater management measures.(A graphic of pinch point 3.1 is provided in the following pages).

Pinch Point 3.2 extends for 1,400 feet from 300 feet north of the Overlook Ave/ Defense Boulevard (S) intersection to the Overlook Ave/I-295 gore point. Within this pinch point Overlook Ave is proposed to be reduced to a single 18-foot wide travel lane with a 10-foot trail, 5-foot separation, and 2-foot buffer. (Traffic study alternative ‘A’ is recommended). These improvements would provide a 17-foot wide segment for the trail and buffers.

(A graphic of pinch point 3.2 is provided in the following pages).

Pinch Point 3.3 extends for 1,300 feet from the Overlook Ave/I-295 gore point to the Overlook Ave/South Capitol Street gore point. Currently a 12-foot wide pinch point is created by the military base wall, signs, utilities, and light poles adjacent to the travelway. This pinch point is proposed for Overlook Ave to be reduced by to a single 18-foot wide travel lane with a 10-foot trail, 5-foot separation, and 2-foot buffer. (Traffic study alternative ‘A’ is recommended). These improvements would ultimately provide a 17-foot wide segment for the trail and buffers.

(A graphic of pinch point 3.3 is provided in the following pages).

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pinch poinTs 2 To 4 Traffic analysis



Table 12. Comparison of Existing and Alternative Capacity Analysis at Pinch Point #1 [Overlook Avenue and Laboratory Road] AM (PM)

The results of the capacity analysis for this proposed alternative indicate that the intersection of Overlook Avenue and Laboratory Road will continue to operate at a Level of Service C or better during both AM and PM peak hours. Pinch Point #2 (Overlook Avenue & Defense Boulevard) The next identified pinch point is the intersection of Overlook Avenue and Defense Boulevard. Proposed measures for Alternative A at this intersection includes eliminating one (1) southbound through lane, and reducing the storage length for southbound right-turn lane at the intersection of Overlook Avenue and Magazine Road. The lane configuration for the proposed alternative is illustrated in Figure 5. Intersection capacity analysis was performed for the proposed alternative, using the HCM methodology. The results of the capacity analysis for this alternative indicate that the intersection of Overlook Avenue and Defense Boulevard will continue to operate at a Level of Service B for both AM and PM peak hours with a slightly increased delay of 15.4 sec/veh and 17.1 sec/veh during AM and PM peak hours, respectively. Alternative B consists of retaining the existing configuration, thus no further traffic analysis was performed for this alternative. The results of the alternative analyses are summarized in Table 13.


(sec/veh) v/c Ratio

Level of Service


Alternative A – retain existing configuration Same as existing configuration

Alternative B – retain existing configuration and eliminate one northbound thru lane on Overlook Avenue

Signal 13.0 (21.3) 0.47 (0.66) B (C)



Table 13. Comparison of Existing and Alternative Capacity Analysis at Pinch Point #2 [Overlook Avenue and Defense Boulevard (S)] AM (PM)

1 – Level of Service and Delay values reflect most accurate values based on optimizing the signal timing splits while maintaining same cycle lengths as under the existing conditions.

Pinch Point #3 (Overlook Avenue/South Capitol Street gore point) The next identified pinch point is the section between Overlook Avenue/ South Capitol Street diverge ramp to intersection of South Capitol Street and Defense Boulevard. This section was analyzed under the following three (3) locations for their distinct characteristics and constraints.

• 3.1 - between Defense Blvd/Overlook Ave and 300 ft south of the intersection o Alternative A: reduce three (3) southbound lanes on Overlook Avenue to two (2) lanes

to a point of approximately 300 ft south of Overlook Avenue and Defense Boulevard intersection.

o Alternative B: retain existing configuration

• 3.2 - between Overlook Ave/ I-295 gore point to 300 ft north of Defense Blvd/Overlook Ave intersection

o Alternative A: reduce two (2) southbound lanes on Overlook Avenue to one (1) lane, starting approximately 300 ft north of Overlook Avenue and Defense Boulevard intersection.

o Alternative B: retain existing configuration • 3.3 - between South Capitol St/Overlook Ave gore point and Overlook Ave/ I-295 gore point

o Alternative A: reduce ramp lane width from 23 ft to 18 ft o Alternative B: retain existing configuration


(sec/veh) v/c Ratio

Level of Service

Existing Signal 13.6 (15.8) 0.36 (0.42) B (B)

Alternative A – Eliminating one southbound through lane Signal1 15.4 (17.1) 0.49 (0.60) B (B)

Alternative B – retain existing configuration Same as existing configuration

Pinch point 4 - View South along South Capitol StreetSource: TDG Library














(sec/veh) v/c Ratio

Level of Service




Pinch Point 4 – From Overlook Ave/South Capitol Street gore point to approximately 400-feet North of South Capitol Street diverge gore a 250-foot long 6-foot wide pinch point is created by the military base wall, several utilities, signage and light poles. Proposed measures at this pinch point are to create 17 feet of available space through the reduction of South Capitol Street to two travel lanes with a 10-foot trail, 5-foot separation and 2-foot buffer. (Traffic study alternative ‘A’ is recommended).

(A graphic of pinch point 4 is provided in the following pages).

(For full report, refer to Appendix B)

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(sec/veh) v/c Ratio

Level of Service





Table 15. Comparison of Existing and Alternative Capacity Analysis Results for Pinch Point #4

Pinch Point #5 (South Capitol Street & MacDill Blvd./Malcolm X Ave. south of intersection) The next identified pinch point is the segment to the south of South Capitol Street and MacDill Boulevard/Malcolm X Avenue intersection (approximately 750 ft). This location is constrained due to the combination of the bus stop located at the southwestern quadrant of the intersection (southbound - far side), and limited right-of-way along the segment. South Capitol Street southbound ramp lane is 22 ft wide and is shared with the bus stop. Alternative A at this pinch point includes reducing the existing ramp lane width from 22 ft to 18 ft and providing an 8-ft trail alignment with a 2-ft buffer, and 4-ft separation/bus stop area. Reducing the ramp lane width from 22 ft to 18 ft would not change the capacity of the ramp; therefore, no further analysis was performed for this alternative. Alternative B includes retaining the existing lane configuration and providing an 8-ft trail alignment with limited separation/buffer zone by delineating the lane where the bus stop is located, and, therefore, no further analysis was performed for this alternative. WMATA bus routes A9, W13, W14, P17, P18, and p19 run along South Capitol Street within the study area and they make scheduled stops at the subject bus stop. Bus route A9 runs with 10/15-minute headways during AM commuter hours and approximately 20/30-minute headways during PM commuter hours. The bus routes W13 and W14 run with 60-minute headways during both AM and PM commuter hours. Under either alternative scenario, the bus stop will be shared with the vehicular travel lane. Although not quantifiable with traditional analysis methodologies, there could be minimal interference expected under Alternative A, while the buses intermediately stop for loading and unloading passengers with a minimal dwelling time (i.e., 60 sec or less) at the bus stop.

Condition Qty of Lanes

Speed [mph]

AM (PM)

Density [pc/mi/ln] AM (PM)

LOS AM (PM)

Existing 3 47.1 (45.7) 6.2 (9.6) A (A)

Alternative A – reduce to two lanes 2 47.1 (45.7) 6.2 (9.6) A (A)

Alternative B – retain existing configuration Same as existing conditions


Using the HCM methodology, intersection and ramp diverge capacity analysis was performed for the aforementioned three sub-segments. The results of the capacity analysis results indicate that the ramp diverge is expected to operate at a Level of Service B or better during both AM and PM peak hours under the existing and proposed conditions. Both of the analyzed intersections are expected to operate at a Level of Service C or better during both AM and PM peak hours under the existing and proposed conditions. The results of the alternatives analyses for both the AM and PM peak hours are summarized in Table 14. Table 14. Summary of Alternatives Analysis for Pinch Point #3 [AM (PM)]


Pinch Point #4 (Overlook Avenue/ South Capitol Street gore point to 400’north) Pinch point 4 is the Overlook Ave/ South Capitol Street diverge to approximately 400 ft north of diverge. This location is constrained with utility poles, military base wall, signage, and limited right-of-way. Alternative A includes reducing the three (3) southbound lanes on South Capitol Street to two (2) lanes. This modification would accommodate a 10-ft trail, 5-ft separation area, and 2-ft buffer zone. The results of the capacity analysis for this alternative indicate that the diverge ramp at South Capitol Street to Overlook Avenue will continue to operate at a Level of Service A during both peak hours. Alternative B consists of retaining the existing configuration, thus no further traffic analysis was performed for this alternative. The results of the analysis is compared with existing conditions are summarized in Table 15.

Condition Control/ Segment

Delay (sec/veh) or Speed

(mph)

v/c Ratio or Density (pc/mi/ln)

Level of Service

Pinch Point 3.1 Delay

(sec/veh) v/c Ratio


Alternative A - reduced southbound lanes on Overlook Avenue, 300 ft south of Overlook Avenue and Defense Blvd intersection

Signal1 10.5 (18.1) 0.45 (0.68) B (B)



(sec/veh) v/c Ratio


Alternative A - reduced southbound lanes on Overlook Avenue, 300 ft north of Overlook Avenue and Defense Blvd intersection

Signal1 15.4 (17.1) 0.49 (0.60) B (B)


Pinch Point 3.3 Speed (mph)

Density (pc/mi/ln)

Existing Ramp

Diverge 47.6 (46.8) 7.9 (11.9) A (B)

Alternative A - reduced ramp lane width Same as existing conditions Alternative B – retain existing configuration Same as existing conditions







(mph)


Level of Service


(sec/veh) v/c Ratio



Signal1 10.5 (18.1) 0.45 (0.68) B (B)



(sec/veh) v/c Ratio



Signal1 15.4 (17.1) 0.49 (0.60) B (B)



Density (pc/mi/ln)

Existing Ramp

Diverge 47.6 (46.8) 7.9 (11.9) A (B)








(mph)


Level of Service


(sec/veh) v/c Ratio



Signal1 10.5 (18.1) 0.45 (0.68) B (B)



(sec/veh) v/c Ratio



Signal1 15.4 (17.1) 0.49 (0.60) B (B)



Density (pc/mi/ln)

Existing Ramp

Diverge 47.6 (46.8) 7.9 (11.9) A (B)


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concepT plan area B - overview pinch points 2 to 4

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pinch poinTs 2 + 3.1 (sheeT a) - defense Blvd concept plAn AreA B


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pinch poinT 3.1 (sheeT B) - overlooK ave concept plAn AreA B


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pinch poinT 3.2 (sheeT a) - overlooK ave concept plAn AreA B


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pinch poinT 3.2 (sheeT B) - overlooK ave concept plAn AreA B


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South Capitol Street Trail Draft Concept Plan Chapter 4, pages 20-34

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