Army Navy Drive Supplemental Traffic Analysis Memorandum · Army Navy Drive Traffic Analysis Project #: 11834 Task 32 November 13, 2017 Page 2 Kittelson & Associates, Inc. Reston,

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MEMORANDUM

Date: November 13, 2017 Project #: 11834 Task 32

To: Jon Lawler

Arlington County Division of Traffic

2100 Clarendon Boulevard, Suite 900

Arlington, Virginia 22201

From: Brandon Nevers, P.E., Jon Crisafi, P.E., Laura Zhao

Project: Army Navy Drive Traffic Analysis

Subject: Supplemental Traffic Analysis Memorandum

This memorandum details the work performed for the Optional Task effort of the Army Navy Drive

Traffic Analysis.

EXECUTIVE SUMMARY

The Optional Task was designed as an effort to follow-up on the lessons learned from the original

assessment (Reference 1) of the Arlington County (County) design concept for Army Navy Drive

between S Joyce Street and 12th Street S. The scope of the Optional Task is to analyze the new design

concept and evaluate the new features compared to the original models (“Original” design concept).

This next iteration of the design concept was aimed toward developing 30% design plans of the corridor

that could be presented to the public and stakeholders for feedback.

This effort focused on the 2020 and 2040 “Build” scenarios only for both AM and PM peak periods.

Arlington County staffed revised the previous design concept to a “new baseline” condition focusing

largely on lane configuration and turn lane lengths. The Build scenarios were updated with these new

baseline features to compare against the latest models analyzed.

The S Hayes Street/Army Navy Drive intersection, identified as the most critical of the corridor due to

its direction connection to Interstate-395 and Route 27 (S Washington Boulevard), was investigated

further with a series of “experimental modifications” to vet possible design features to improve the

operations. The mitigations at the Hayes Street intersection evaluated were:

Dual southbound left-turn lanes;

Eastbound protect + overlap right-turn phasing, and;

Removal of the channelized westbound right turn.

Army Navy Drive Traffic Analysis Project #: 11834 Task 32 November 13, 2017 Page 2

Kittelson & Associates, Inc. Reston, Virginia

The evaluation of these mitigations vetted that only the “eastbound protected + overlap right-turn

phasing” should be carried forward for the new final models.

New ultimate models showed a general improvement from the previous models in terms of network

operations and individual intersection performance.

SCOPE OF OPTIONAL TASK

The Optional Task was designed as an effort to follow-up on the lessons learned from the original

assessment of the Arlington County (County) design concept for Army Navy Drive between S Joyce

Street and 12th Street S. The scope of the Optional Task is to analyze the new design concept and

evaluate the new features compared to the Original models. This next iteration of the design concept

was aimed toward developing 30% design plans of the corridor that could be presented to the public

and stakeholders for feedback.

The full scope of the Optional Task is outlined as the following:

Model and analyze the New Baseline design concept;

Evaluate “experimental modifications” at the Hayes Street/Army Navy Drive intersection;

Model and analyze the newly developed “Ultimate” design concept, and;

Conduct and prepare a marked crossing study, per the Arlington County Marked Crosswalk

Guidelines, for the existing unmarked crossing east of the Eads Street/Army Navy Drive

intersection on the US 110 off-ramp.

The marked crossing study (Reference 2) was prepared for addressing concerns VDOT raised during the

original analysis of that particular crossing location. The study was prepared and submitted to Arlington

County independent of this memo.

NEW BASELINE DESIGN CONCEPT

After the submission of the original traffic analysis report, County staff revised the corridor design

concept considering the findings and recommendations provided. These revisions established a “new

baseline” to evaluate. Part of the Optional Task effort was to model these revisions and compare

operational results to the Original models. Since these are applicable only to the proposed design

concept, only 2020 and 2040 AM and PM Build scenarios were analyzed.

The New Baseline was created by updating the Original models with the following modifications:

Modify turn lanes to reflect the following storage and tapers:

o Pentagon City Mall Entrance- dual WB left turn lane: 130-ft storage, 80-ft taper;

o S Hayes St – EB left turn lane: 205-ft storage, 90-ft taper;

o S Hayes St – WB left turn lane: 125-ft storage, 80-ft taper;

o S Fern St – EB left turn lane: 150-ft storage, 70-ft taper;



o S Fern St – WB left turn lane: 50-ft storage, 95-ft taper;

o S Eads St – EB left turn lane: 415-ft storage, 85-taper, and;

o S Eads St – WB right turn lane: 50-ft storage, 175-ft taper.

Bus stop modifications:

o Remove near-side bus stop on southwest corner of S Hayes St/Army Navy Dr.

o Expand mid-block bus stop between S Joyce St and Pentagon City Mall Garage Entrance

westward for a total length of 120-ft.

Pentagon City Mall Garage Intersection Modifications

o Reconfigure the west bound approach to include the dual left-turn lanes.

o Optimize signal timing and corridor offsets as needed.

S Hayes St Intersection Modifications

o Add new crosswalk on north side of intersection; adjust signal timing to include

pedestrian interval.

S Eads St Intersection Modifications

o I-395 HOT Lane Widening Improvements – the following adjustments are to be made to

the southbound approach (north leg) of the S Eads St intersection:

Approach should be configured with one 230-ft long left turn storage lane, one

thru lane, and one 80-ft right turn storage lane.

The receiving lanes on the north leg should be widened from one lane to two

lanes.

Assess operational need to determine protected/permissive side-street left turn

phasing improves operations.

Optimize signal timing and corridor offsets as needed.

o Reorient the west crosswalk and eastbound stop bars to reflect adjustments in design

concept.

o Remove the westbound left turn lane and reconfigure the westbound approach to two

(2) thru lanes and a dedicated right turn lane.

Configure the US 110 off-ramp to align with middle thru lane and add the

dedicated right turn lane, per design concept.

o Reroute traffic impacted by left turn removal through network as needed.

o Optimize signal timings and corridor offsets as needed.

Army Navy Drive/12th St S Intersection Modifications

o Reconfigure westbound approach to allow left turns from the transit lane.

Reroute the U-turns at S Eads St/12th St S to this movement.

EXPERIMENTAL MODIFICATIONS AT HAYES STREET

Recognizing the Hayes Street/Army Navy Drive intersection as a key congestion point in the corridor

(particularly because of its direction connection to Interstate-395 and Route 27 [S Washington

Boulevard]), modifications to new baseline models at the intersection were analyzed for their



operational impact. These “experimental modifications” would be analyzed and reviewed and decided

by County staff for each modifications ultimate inclusion or exclusion from the final models.

Both peak hours exhibit high turning volumes and are shown in Figure 1.

Figure 1 - 2040 Hayes Street/Army Navy Drive Turning Movement Volumes

Modifications

The following modifications were analyzed at the S Hayes Street/Army Navy Drive intersection:

Dual southbound left-turn lanes;

Eastbound protected + overlap only right-turn phasing, and;

Removal of the channelized westbound right turn.

Dual southbound left turn lanes

The southbound left turns arriving from the I-395/Route 27 (S Washington Boulevard) freeway system

draws some of the heaviest demand in the analysis corridor. One of the bottlenecks results from a high

left turn demand being channeled through a single left-turn lane. Addressing this issue, this

modification will:

Reconfigure the southbound approach with dual left-turn lanes and dual thru lanes

Phase the southbound left turns as protected only

o Optimize intersection timing and adjust corridor offsets to reflect this capacity change.



Eastbound protect + overlap only right-turn phasing

The presence of a two-way cycle track on the south side of Army Navy Drive presents safety challenges

for eastbound right turns along the corridor. At the Hayes Street/Army Navy Drive intersection, there

are many conflicts with a heavy right turn demand and non-motorized users (both cyclists and

pedestrians). Given westbound cyclists are essentially “contraflow” to the adjacent eastbound vehicles,

right turning traffic must now yield to an unconventional movement when phased permissively. By

restricting right turns to protected only in addition to overlapping with the northbound left turns, the

conflicts with adjacent non-motorized users is eliminated entirely. Addressing this issue, this

modification will:

Phase the EB right turns as protected only + overlap with NB left turns.

Assess the queuing impacts on the eastbound approach and eastbound travel times.

o Severity of impact will be reported by KAI and the County will determine whether to

move forward with the protected + overlap phasing or to engage Optional Task 1

adjustment

Removal of the channelized westbound right turn

The existing westbound channelized right turn provides an easier movement for westbound right-

turning vehicles to access the I-395 South/Route 27 (S Washington Boulevard) West on-ramp by

allowing for higher speed turn bypassing the signal control. However, this higher speed movement

presents a safety issue for pedestrians crossing the north side of the Hayes Street/Army Navy Drive

intersection. Removing the channelization and bringing the dedicated right-turn lane to the intersection

would improve pedestrian safety, but likely increase delay and queuing for westbound right turns.

Addressing this issue, this modification will:

Reconfigure the westbound approach to remove the channelized right and bring the dedicated

right turn lane to the intersection stop bar.

o Dedicated right turn lane will permit westbound buses to go thru from this lane

Assess impact to queues, delays, and westbound travel time between S Hayes St and S Eads St

Scenarios Tested

The following scenarios were developed and tested for evaluating the mitigations proposed to the

Hayes Street/Army Navy Drive intersection (summarized in Table 1). Each scenario was tested under

2040 AM and PM peak volume conditions to assess the most conservative operations for the proposed

mitigations.



Table 1 - Scenario Description Summary

No. Scenario Description

1 New Baseline Model Includes all Task 3 “New Baseline Modifications”

2 Dual SB LT Lanes

Includes all Task 3 “New Baseline Modifications”

Configures SB Hayes Street approach (off-ramp) as L-L-T-TR

Adjusts Hayes/AND timings to accommodate new lane configuration

Reconfigures WB channelized right turn to dedicated right turn lane (signalized) o Allows WB thru movements for bus only

3 EB Right Turn Protected+ Overlap Phasing


Includes EB protected right-turn phase (Φ9)

Prohibits permissive EB right turns

Adjusts Hayes/AND timings to accommodate new phasing


4 All Hayes Mitigations


Configures SB Hayes Street approach (off-ramp) as L-L-T-TR

Includes EB protected right-turn phase (Φ9)

Prohibits permissive EB right turns

Adjusts Hayes/AND timings to accommodate new phasing


Results/Findings

The following tables summarize the traffic signal phasing assumptions (Table 2) and operational results

(Table 3 and Table 4) of the experimental modifications.

Table 2 - Hayes Street/Army Navy Drive Phasing and Splits by Testing Scenario

Approach Movement

AM Peak PM Peak

Original 2040

New Baseline

Dual SB LT

RT Prot+ Ovlp All Mit.

Original 2040

New Baseline

Dual SB LT


Phase/Split Time (s)

Northbound

Left Φ1/19 Φ1/21 Φ1/15 Φ1/23 Φ1/15 Φ1/36 Φ1/36 Φ1/36 Φ1/38 Φ1/32

Thru Φ6/36 Φ6/37 Φ6/41 Φ6/36 Φ6/39 Φ6/41 Φ6/42 Φ6/66 Φ6/41 Φ6/59

Right Φ6/36 Φ6/37 Φ6/41 Φ6/36 Φ6/39 Φ6/41 Φ6/42 Φ6/66 Φ6/41 Φ6/59

Southbound

Left Φ5/38 Φ5/38 Φ5/34 Φ5/34 Φ5/31 Φ5/38 Φ5/31 Φ5/22 Φ5/36 Φ5/15

Thru Φ2/54 Φ2/54 Φ2/60 Φ2/47 Φ2/55 Φ2/54 Φ2/37 Φ2/52 Φ2/39 Φ2/42

Right Φ2/54 Φ2/54 Φ2/60 Φ2/47 Φ2/55 Φ2/54 Φ2/27 Φ2/52 Φ2/39 Φ2/42

Eastbound

Left Φ3/13 Φ3/13 Φ3/13 Φ3/12 Φ3/12 Φ3/13 Φ3/22 Φ3/19 Φ3/25 Φ3/24

Thru Φ8/32 Φ8/32 Φ8/32 OvC2/32

+23 OvC2/32

+12 Φ8/32 Φ8/42 Φ8/33

OvC2/32 +12

OvC2/32+12

Right OvA

1/32

+21 OvA

1/32

+21 OvA

1/32

+15 OvB

2/12

+23 OvB

2/12

+15 OvA

1/32

+21 OvA

1/42

+36 OvA

1/33

+36 OvB

2/12

+38 OvB

2/12

+32

Westbound

Left Φ7/33 Φ7/33 Φ7/33 Φ7/26 Φ7/26 Φ7/33 Φ7/25 Φ7/19 Φ7/19 Φ7/22

Thru Φ4/52 Φ4/52 Φ4/52 Φ4/58 Φ4/58 Φ4/52 Φ4/45 Φ4/33 Φ4/38 Φ4/42

Right Free Free Φ4/52 Φ4/58 Φ4/58 Free Free Φ4/33 Φ4/38 Φ4/42



Table 3 - Hayes Street/Army Navy Drive Operations by Testing Scenario

Approach Movement

AM Peak PM Peak

Original 2040

New Baseline

Dual SB LT


Original 2040

New Baseline

Dual SB LT


Delay (s)

Northbound

Left 242.0 85.5 284.0 117.5 547.2 143.2 142.9 145.2 193.3 302.5

Thru 47.6 45.4 42.2 47.3 55.7 52.7 78.8 52.9 62.2 87.7

Right 46.5 41.4 39.8 45.3 53.7 59.2 71.7 58.9 58.0 89.5

TOTAL 84.5 53.1 87.1 61.2 134.8 79.8 96.9 80.2 99.3 147.8

Southbound

Left 204.5 134.2 66.9 236.4 104.5 299.3 268.5 127.6 164.7 380.4

Thru 120.3 38.7 98.6 77.2 136.9 69.7 49.2 43.3 50.7 97.7

Right 146.8 18.8 77.3 50.9 106.5 28.3 15.1 21.3 24.0 70.2

TOTAL 140.5 57.3 88.7 105.8 126.2 95.1 76.9 53.0 64.6 138.3

Eastbound

Left 42.1 95.6 92.7 102.4 117.7 62.8 139.0 236.9 123.5 114.8

Thru 44.5 21.8 20.0 35.0 115.8 42.9 74.4 103.0 113.4 83.0

Right 63.8 25.5 26.9 103.8 363.7 21.9 26.7 32.1 41.3 45.7

TOTAL 51.6 25.7 25.1 61.8 193.1 41.9 76.0 112.4 95.5 80.2

Westbound

Left 72.5 61.6 61.6 54.9 57.4 94.6 95.3 133.7 116.3 104.2

Thru 71.8 38.6 35.4 30.3 27.2 48.3 39.8 77.3 72.2 49.3

Right 8.4 0.7 22.7 13.9 16.8 11.3 0.8 58.0 49.1 40.9

TOTAL 35.5 18.3 30.3 22.7 23.5 32.8 23.9 70.4 63.4 47.2

Max Queuing (ft)

Northbound

Left 505 90 565 340 738 761 254 755 814 902

Thru 348 59 414 222 660 576 247 563 558 541

Right 256 50 220 163 307 386 146 396 246 750

Southbound

Left 1663 403 1669 1685 1695 999 386 680 759 1192

Thru 1663 403 1669 1685 1695 999 386 680 759 1192

Right 1656 196 1076 1260 1538 849 357 466 468 1135

Eastbound

Left 190 25 83 82 76 387 220 905 808 769

Thru 512 118 357 495 645 336 216 902 776 740

Right 92 118 357 495 645 336 216 673 703 900

Westbound

Left 397 37 234 123 130 74 24 74 93 97

Thru 394 80 312 249 251 565 147 566 562 563

Right 399 0 317 497 463 467 0 74 93 97

Table 4 - Corridor Travel Time* Comparison Between Testing Scenarios

Route

AM Peak PM Peak

Original 2040

New Baseline

Dual SB LT


Original 2040

New Baseline

Dual SB LT


EB All Traffic 284.5 156.4 144.8 148.2 281.5 352.7 424.2 483.1 494.9 443.3

WB All Traffic 237.1 149.0 146.9 143.5 175.0 198.6 123.4 235.6 198.8 166.7

EB Transit 406.3 218.2 203.4 222.0 407.4 415.6 442.6 439.3 459.8 436.1

WB Transit 237.1 198.2 206.5 191.3 194.5 222.3 210.8 332.9 282.6 256.6

*Travel times are routes that extend from Joyce Street to/from Eads Street



Findings and Conclusions from Experimental Modifications

Based on the results of the experimental modifications, the following conclusions and findings are

summarized per design feature:

New Baseline

The modifications included in the New Baseline configuration makes notable improvements over the

previous baseline in terms of traffic operations for the following reasons:

Generally, the improvements to dedicated turn lanes at Parking Garage and Eads Street allows

for better processing of traffic along Army Navy Drive.

Westbound left-turn at Parking Garage do not spillback into the through lane or Hayes Street,

better processing Hayes Street northbound left-turns. Previously these northbound left-turns

would spillback and block Hayes Street SB through traffic.

Improvements at Eads Street, notably the expansion of the north approach typical section,

reduces the severity of queue spillback and providing better traffic flow for Hayes Street

southbound left turns the space to receive traffic flow.

Westbound travel times improve significantly during both AM and PM peak hours.

Dual Southbound Left Turn Lanes

Reconfiguring the southbound approach at S Hayes Street with dual left-turn lanes and dual

through lanes does not improve the queuing on the approach.

o Delay for left turns decreases but increase for the through movement.

o Overall back of queue increases from 400-ft to over 1650-ft (compared to New Baseline)

during the PM peak.

o Through queue extends further than new baseline because of limited through capacity

versus high demand.

Configuration requires additional modifications to northbound Hayes approach to provide

positive offset of northbound/southbound left turns.

Eastbound Right Turn Protected + Overlap Phasing

Despite maximizing the cycle length for 140-seconds, the protected + overlap ONLY phasing

cannot provide enough green time to process the eastbound right-turn traffic demand.

o Eastbound queue spillback from Hayes Street impacts operations at Parking Garage and

Joyce Street intersections.

o Delays and queues impede all EB approach (throughs and lefts) west of Hayes Street,

reducing overall throughput of the corridor.



Westbound Channelized Right Removal

Westbound delays and queues increase with the removal of the channelization.

o Despite increased queue length, removal of the channelization does not fill the block

storage or cause upstream traffic issues.

Critical to maintaining the channelization, the roadway segment between S Fern Street and S

Hayes Street must include the add-lane storage and taper depicted in Option 1.

Conclusion for Ultimate Models

Based on the findings of the experimental modifications, the following decisions were made in

coordination with the County on what features at the S Hayes Street/Army Navy Drive intersection to

include in the Ultimate design concept model:

Southbound Approach - Maintain the existing lane configuration of a single dedicated left-turn

lane, three through lanes, and a channelized right-turn. Southbound left-turn movement is

modeled as protected only in all scenarios.

Eastbound Approach – Signal plan is to include the eastbound right-turn protected + overlap

ONLY phasing and protected only left-turn phasing.

Westbound Approach – Maintain the existing channelized right turn and configure with the

Option 1 concept produced by the County for the westbound segment between S Fern Street

and S Hayes Street.

FINAL MODEL ANALYSIS RESULTS

The Ultimate build models (2020/2040, AM and PM peaks) were built and simulated to compile

operations results at the intersection and network levels. The ultimate lane configurations and traffic

control devices are summarized in Figure 2. Intersection operations are detailed in Attachment A.

Network Wide Performance

The variability of signalized arterial networks makes analysis of individual intersections difficult to

evaluate overall traffic operations. Because intersections are closely spaced (generally around 600-ft,

stop bar-to-stop bar), a variety of factors affect individual intersection performance that may not be

indicative of actual traffic conditions, including:

Variations in signal timing/phasing;

Platoon progression, and;

Impacts of residual queues/queue spillback.



To better compare the operational impact of the Ultimate versus Original design concepts, network-

wide average delay, transit travel times, and the southbound queuing at S Hayes Street were used as

primary performance measures. The following section and graphs demonstrate these network level

performance measures across the different analyzed scenarios.

Average Network Delay

One parameter worth examining is the average network delay experienced by drivers under different

scenarios. Average network delay is calculated from the total delay measured in the study network

divided by the total user throughput. The total throughput can include all users, as shown in Figure 3,

or be refined to different vehicle classes like passenger cars (Figure 4) and transit (Figure 5).

Percentages indicate percent change comparing Ultimate to corresponding Original model.

Figure 3 - Average Network Delay for All Vehicles by Scenario

0

50

100

150

200

2015 2020 2040 2015 2020 2040

All All

AM PM

Ave

rage

De

lay

(se

c/ve

h)

Original Build Existing Build

+9.4%

-16.8%

-27.9%

-25.5%



Figure 4 - Average Network Delay for Passenger Cars by Scenario

Figure 5 - Average Network Delay for Transit by Scenario

0

50

100

150

200

250

2015 2020 2040 2015 2020 2040

Cars Cars

AM PM

Ave

rage

De

lay

(se

c/ve

h)


0

50

100

150

200

250

300

2015 2020 2040 2015 2020 2040

Transit Transit

AM PM

Ave

rage

De

lay

(se

c/ve

h)


+10.6%

-21.0% -35.4%

-31.0%

-37.6% -31.1%

-3.3%

-40.5%



The primary finding from these network wide results is that the new ultimate build model improves

average delay for both passenger cars and transit, suggesting the mitigations investigated do improve

the overall network. Notable instances show the Original build performing better than the new

ultimate build (e.g. all vehicles/passenger car delay 2020 AM). This has been found to be related to the

signal timing changes at S Eads Street/Army Navy Drive, where the north and south legs have been

expanded to include protected left turn phases. These additional phases require more of the cycle

length, limiting green time for the east-west phases. However, by 2040, traffic demands across all

approaches rises enough to realize the benefit of the protected/permissive phasing of the north and

south legs, resulting in a better overall performance. Both 2020 and 2040 PM scenarios operate better

for transit average network delay compared to the Original build.

Transit Route Travel Times

Transit-specific travel times were used to help explain the impact of difference scenarios to individual

transit routes. The multi-modal goals of the design concept aim to enhance transit service along the

corridor and reduce travel times and/or improve transit reliability. The Original design concept was

found to increase travel times due to a number of issues, most notably the nearside stop location at

Hayes Street (eastbound). The Ultimate design concept removes this stop location and expands the

mid-block transit stop between S Joyce Street and Parking Garage intersections.

Table 5 summarizes the transit travel times between S Joyce Street and S Eads Street during the peak

periods and the comparative performance between the Original and Ultimate design concepts.

Table 5 Transit Travel Times Comparison between Original and Ultimate Build Scenarios

Direction Route

Weekday AM Peak Hour

2020 2040

Original Ultimate Original Ultimate

Eastbound Joyce to Hayes* 343.5 143.5 226.2 167.2

Hayes to Eads* 87.0 45.1 170.0 114.1

Westbound Eads to Hayes 157.2 144.6 182.9 175.6

Hayes to Joyce 112.0 124.7 145.3 86.3

Direction Route

Weekday PM Peak Hour

2020 2040

Original Ultimate Original Ultimate

Eastbound Joyce to Hayes 185.6 115.5 163.7 126.9

Hayes to Eads 103.0 133.7 247.2 157.4

Westbound Eads to Hayes* 168.8 205.3 171.5 194.5

Hayes to Joyce* 93.6 120.0 105.4 125.7

*indicates peak direction



As shown in Table 5, 2020 and 2040 AM transit travel times have notably improved under the Ultimate

design concept compared to the Original in both directions of the Army Navy Drive corridor. This is

likely attributable to the roadway improvements along Army Navy Drive and the Eads S Street

intersection to better process queues and avoid excessive delays due to queue spillback.

Similar findings are shown during the PM peak for the eastbound transit routes where the Ultimate

design concept decreases travel times compared to the Original, but not for westbound transit routes.

The reason for westbound transit travel times increasing compared to the Original design concept is

likely an amalgamation of traffic patterns and the signal progression of the corridor.

Queuing

The intersection at S Hayes Street/Army Navy Drive is of particular importance because of its

connection to I-395 and Washington Boulevard, with the southbound approach serving as the

freeway’s off-ramps to Army Navy Drive. A priority goal for the design concept must include mitigating

queues on this approach as to not spillback onto the freeway. Examining the full queue storage

available on the approach is shown in Figure 6. In VISSIM models, the queues are modeled from one

single ramp whereas in reality vehicles accumulating the queues are from two ramps (i.e., Washington

Blvd and I-395 ramp) as shown in Figure 6.

Figure 6 – Measured Southbound Queue Storage at S Hayes Street/Army Navy Drive

The shortest queue storage is from Washington Blvd at 1,970 feet. This storage distance serves as the

threshold no maximum queue may extend past to be considered acceptable. Furthermore, because the

maximum modeled queues will, in reality, be divided between the I-395 ramp and Washington Blvd

ramp, the maximum queue distance on either ramp will always be less than the maximum queue

reported. Findings from the original analysis showed that queues were accommodated by the Original

design concept, however finding means of reducing queue lengths further were pursued to provide

greater reliability the storage would be sufficient.

Table 6 summarizes the maximum simulated queues for southbound movements at S Hayes

Street/Army Navy Drive between the Original and Ultimate design concepts.



Table 6 Maximum Simulated Queues at Southbound Hayes Street/Army Navy Drive Intersection

Scenario Storage (ft) Original Max

Queue (ft) Ultimate Max

Queue (ft) Adequate Storage?

2020 AM 1,970 950 1,690 YES

2020 PM 1,970 425 440 YES

2040 AM 1,970 1,675 1,695 YES

2040 PM 1,970 1,000 450 YES

Examining queues produced between both Original and Ultimate design concepts show that both

models produce queues that are adequate for the storage provided. The Ultimate design concept

generally does not improve queuing compared to the Original due to the inclusion of the protected

eastbound right turn phase. The inclusion of this phase does show a slight increase in 2020 queuing for

both AM and PM peak periods, consistent queuing for the 2040 AM and improved queuing for the 2040

PM.

FINDINGS AND CONCLUSIONS

Based on the analysis results of the Ultimate models the following findings have been summarized in

terms of overall operations:

The Ultimate design concept outperforms the Original in terms of reducing average network

wide delay for all vehicles for both 2020 and 2040 AM and PM peak scenarios. The

improvements to lane configurations made along Army Navy Drive and at the S Eads Street

intersection improve traffic throughput along the corridor.

o Average network wide delay is reduced for both passenger cars and transit vehicles

under the Ultimate design concept compared to the Original for all scenarios.

The Ultimate design concept does not improve queueing on southbound S Hayes Street

compared to the Original, but does not exceed storage length.

The new baseline adjustments have contributed to the performance of the Ultimate design concept.

The following findings have been summarized for these modifications:

Turn Lane Storage and Taper adjustments: all adjustments to turn lanes have been shown to

adequately accommodate demands.

Bus Stop Consolidation: Consolidating the eastbound bus stops between S Joyce Street and S

Hayes Street have improved traffic flow and reduced bus blockages at S Hayes Street.

Pentagon City Mall Garage Intersection Dual Left-turn Lanes: dual left-turn lane configuration

greatly improves throughput of westbound traffic between S Hayes Street and Pentagon City

Mall Parking Garage.

S Hayes St Intersection North Crosswalk: implementing the north crosswalk provides additional

pedestrian connectivity with negligible impacts to traffic operations.



S Eads St Intersection Modifications:

o I-395 HOT Lane Widening Improvements: the improvements to the S Eads Street

intersection due to the I-395 HOT lanes have greatly improved the throughput of

vehicles routed to/from the north leg. Expanding the typical section to two-receiving

lanes and dedicated turn lanes on the approach better processes vehicles going to/from

the freeways. Protected/permissive left turn phasing was implemented to favor traffic

operations at this key intersection.

o Westbound approach: Removing the westbound left turn lane and reconfiguring the

westbound approach to two (2) through lanes and a dedicated right turn lane better

processes the vehicle merge of the US 110 off-ramp and Army Navy Drive. Elimination

of westbound left turns reduces lane changes within the short segment.

o Optimize signal timings and corridor offsets as needed.

Army Navy Drive/12th St S Westbound Approach: the minimal left turns on the westbound

approach mixing with the transit lane shows negligible impact and more direct access to the

proximate parking garage.

While the Army Navy Drive corridor experiences peak hour congestion, many of the modifications

proposed in the Ultimate design concept have provided some relief for the high traffic demands. Other

future considerations may include:

Variable lane configurations (e.g. eastbound Army Navy Drive at Eads Street configured

with dual left turn lanes during PM peak period).

Transit signal priority at strategically identified intersections to improve transit

reliability.

Overall, across multiple performance metrics the Ultimate design concept is an improvement over the

Original and is recommended to be advanced forward in the design process.



REFERENCES

1. Army Navy Drive Traffic Study. Kittelson & Associates, Inc. March 2017.

2. Marked Crosswalk Study. Kittelson & Associates, Inc. September 2017.

ATTACHMENTS

Attachment A – Ultimate Build Intersection Operations

Attachment A Ultimate Build Intersection Operations

Army Navy Drive Traffic Study VISSIM Operations Results 2020 Build Conditions

Optional Task - Ultimate Concept

AM Peak Hour

Delay LOS Vehicle Transit Person

Army Navy & Joyce 53 40.56 D 40.82 31.71 39.51 = Main Intersections

Army Navy & Pentagon Mall 54 39.45 D 54.65 NA 54.65

Army Navy & Hayes 28 65.83 E 65.87 65.42 64.74

Army Navy & Fern 35 45.69 D 45.99 34.93 44.89

Army Navy & Eads 34 29.02 C 29.47 16.80 28.57

Army Navy & 12th 27 70.52 E 70.44 82.58 69.89

Joyce 55 7.59 A 7.59 8.59 7.55

12th & Hayes 29 8.36 A 7.95 39.40 7.88

12th & Fern 36 15.90 B 15.77 27.62 15.61

12th & Eads 46 15.91 B 15.73 51.23 15.39

EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR

Movement Delay (sec/veh) 19.6 32.8 32.6 99.3 24.0 4.8 36.2 52.3 35.5 55.8 37.5 22.2

Movement LOS B C C F C A D D D E D C

Approach Delay (sec/veh)

Approach LOS

Average Queue (ft) 81 81 81 78 78 47 5 45 45 108 108 98

95th Percentile Queue (ft) 433 433 433 286 286 288 79 256 256 487 487 490

40.6 D


Movement Delay (sec/veh) 27.2 35.3 51.1 76.8 10.3 14.5 54.6 N/A 29.7 42.9 0.0 12.7

Movement LOS C D D E B B D N/A C D A B


Approach LOS

Average Queue (ft) 110 110 110 92 12 15 1 1 1 2 2 3


39.4 D



Movement LOS F D F F B A F D D F D C


Approach LOS

Average Queue (ft) 12 198 198 25 20 0 96 39 11 1229 1229 387


65.8 E



Movement LOS C D E E D C F E C D C C


Approach LOS

Average Queue (ft) 12 101 87 24 65 67 158 18 18 27 34 32


45.7 D


43.4 42.2 22.8

D D D C

Intersection Delay (sec/veh)


34/I. Army Navy & Eads

Army Navy Eads

Eastbound Westbound Northbound Southbound

40.1 38.4 88.9 33.0

D D F C


35/G. Army Navy & Fern

Army Navy Fern


68.3 15.4 62.6 85.4

E B E F


28/E. Army Navy & Hayes

Army Navy Hayes


29.7 48.9 47.1 49.0

C D D D

54/C. Army Navy & Pentagon Mall

Entrance

Army Navy Pentagon Mall Entrance


36.7

53/A. Army Navy & Joyce

Army Navy Joyce St


Intersection No

Total Traffic Delay

2020 Build Conditions

Ultimate Concept

AM Peak Hour

1 of 2



AM Peak Hour

Movement Delay (sec/veh) 10.3 20.3 10.0 N/A 45.4 8.1 42.4 63.3 69.7 37.1 39.8 9.1

Movement LOS B C A N/A D A D E E D D A


Approach LOS

Average Queue (ft) 40 40 40 N/A 35 40 86 86 86 51 43 2

95th Percentile Queue (ft) 256 256 256 N/A 190 198 431 431 431 396 466 114

29.0 C



Movement LOS E E A A F F D C C E A F


Approach LOS

Average Queue (ft) 150 150 184 93 93 98 7 7 7 425 425 425


70.5 E


Movement Delay (sec/veh) 18.5 - 6.0 19.9 - 5.2 - 6.7 5.0 8.1 7.1 -

Movement LOS C - A C - A - A A A A -


Approach LOS

Average Queue (ft) 2 - 4 2 - 2 - 8 6 1 4 -

95th Percentile Queue (ft) 48 - 68 34 - 40 - 131 135 42 91 -

7.6 A



Movement LOS D D D E C B B A A A A A


Approach LOS

Average Queue (ft) 14 14 15 15 15 15 1 7 1 1 6 7


8.4 A



Movement LOS C C C C C B B B A B B B


Approach LOS

Average Queue (ft) 17 17 18 3 3 4 16 16 20 13 13 12


15.9 B



Movement LOS F D B D C B B B A C B A


Approach LOS

Average Queue (ft) 1 7 11 21 21 23 12 12 12 20 20 22


15.9 BIntersection Delay (sec/veh)

28.1 37.6 7.6 14.3

C D A B





46/V. 12th & Eads

12th Eads


24.6 17.1 11.9 13.9

C B B B

36/S. 12th & Fern

12th Fern


48.5 37.5 7.8 0.0

D D A A

29/Q. 12th & Hayes

12th Hayes


17.7 13.0 6.5 7.2

C B A A

55/O. Joyce

- Joyce


69.9 22.6 34.1 64.8

E C C E


27/M. Army Navy & 12th

12th Army Navy


15.9 35.6 58.1 27.7

B D E C

2 of 2



PM Peak Hour


Army Navy & Joyce 53 34.96 C 34.82 40.02 34.10 = Main Intersections

Army Navy & Pentagon Mall 54 27.88 C 60.58 NA 60.58

Army Navy & Hayes 28 43.61 D 43.70 45.37 43.04

Army Navy & Fern 35 45.34 D 45.31 50.12 44.48

Army Navy & Eads 34 78.87 E 79.18 62.51 77.35

Army Navy & 12th 27 80.84 F 80.73 89.63 80.02

Joyce 55 9.80 A 9.77 22.10 9.74

12th & Hayes 29 12.59 B 12.38 21.16 12.27

12th & Fern 36 23.16 C 23.26 13.59 23.05

12th & Eads 46 25.09 C 25.17 54.19 24.73



Movement LOS C C D E C A D D C D D C


Approach LOS

Average Queue (ft) 37 37 37 134 134 130 47 73 73 107 107 106


35.0 C



Movement LOS C C C E B A E N/A D D A A


Approach LOS

Average Queue (ft) 59 59 59 51 51 57 75 75 75 9 9 12


27.9 C



Movement LOS F C D F D A F D C E D B


Approach LOS

Average Queue (ft) 168 107 107 20 125 0 151 49 9 149 149 2


43.6 D



Movement LOS D B C F C D F E F E C B


Approach LOS

Average Queue (ft) 27 68 19 21 139 142 536 237 237 7 23 20


45.3 D


21.2 55.3 16.3

C C E B




Army Navy Eads


30.1 37.4 94.5 23.3

C D F C



Army Navy Fern


55.2 31.9 49.7 42.6

E C D D



Army Navy Hayes


32.6 27.3 41.7 42.4

C C D D


Entrance



28.9


Army Navy Joyce St


Intersection No

Total Traffic Delay


Ultimate Concept

PM Peak Hour

1 of 2



PM Peak Hour


Movement LOS F C A N/A F F E E F C D B


Approach LOS



78.9 E



Movement LOS E D C A F F D D D E A D


Approach LOS

Average Queue (ft) 43 43 68 452 452 458 10 10 10 82 82 82


80.8 F



Movement LOS C - A C - A - A A B A -


Approach LOS

Average Queue (ft) 1 - 2 7 - 9 - 18 18 2 8 -


9.8 A



Movement LOS D D D D D C B A A A A A


Approach LOS

Average Queue (ft) 29 29 27 30 30 32 4 18 1 2 8 8


12.6 B



Movement LOS C C C B A A B B B A C D


Approach LOS

Average Queue (ft) 28 28 32 0 0 0 12 12 21 35 35 35


23.2 C



Movement LOS A D B D D C D C A B B A


Approach LOS

Average Queue (ft) 171 3 5 30 30 33 65 65 66 17 17 17


25.1 CIntersection Delay (sec/veh)

23.8 38.3 25.4 15.8

C D C B





46/V. 12th & Eads

12th Eads


27.4 8.7 12.0 28.8

C A B C

36/S. 12th & Fern

12th Fern


42.7 35.2 10.3 0.0

D D B A

29/Q. 12th & Hayes

12th Hayes


17.3 13.8 8.9 9.6

C B A A

55/O. Joyce

- Joyce


39.2 26.7 49.8 58.9

D C D E



12th Army Navy


62.5 124.8 72.5 23.2

E F E C

2 of 2



AM Peak Hour



Army Navy & Pentagon Mall 54 42.66 D 53.01 NA 53.01

Army Navy & Hayes 28 81.32 F 81.44 75.06 80.18

Army Navy & Fern 35 33.28 C 33.20 36.97 32.50

Army Navy & Eads 34 56.80 E 57.15 42.28 55.58

Army Navy & 12th 27 93.19 F 93.20 93.86 92.46

Joyce 55 7.54 A 7.52 11.15 7.48

12th & Hayes 29 7.72 A 7.59 15.18 7.53

12th & Fern 36 15.46 B 15.30 32.51 15.15

12th & Eads 46 16.92 B 16.98 37.13 16.63



Movement LOS C D C F D A C D D E D C


Approach LOS

Average Queue (ft) 93 93 93 106 106 89 5 53 53 177 177 161


47.9 D



Movement LOS C D E F A A D N/A C D A B


Approach LOS

Average Queue (ft) 155 155 155 122 6 8 1 1 1 2 2 2


42.7 D



Movement LOS F D F E C A F D D F F E


Approach LOS

Average Queue (ft) 15 205 205 14 42 0 112 52 18 1454 1454 1025


81.3 F



Movement LOS C C C E C C E D C D C C


Approach LOS

Average Queue (ft) 10 57 39 32 62 65 83 14 14 30 40 39


33.3 C


Intersection No

Total Traffic Delay


Ultimate Concept

AM Peak Hour


Army Navy Joyce St




Army Navy Hayes


32.1 64.6 45.8 65.3

C E D E


Entrance



40.3



Army Navy Fern


66.7 19.1 63.9 119.5

E B E F



Army Navy Eads


24.8 35.0 57.3 30.7

C C E C

46.4 37.5 21.8

D D D C


1 of 2



AM Peak Hour


Movement LOS E F F N/A D A E E E D D B


Approach LOS



56.8 E



Movement LOS E E A A E E C C C F A F


Approach LOS

Average Queue (ft) 194 194 229 52 52 53 6 6 6 888 888 888


93.2 F



Movement LOS C - C C - A - A A A A -


Approach LOS

Average Queue (ft) 2 - 2 2 - 2 - 11 10 0 4 -


7.5 A



Movement LOS D D D D D B B A A A A A


Approach LOS

Average Queue (ft) 14 14 15 11 11 11 1 7 1 0 3 3


7.7 A



Movement LOS C C B C C B B B B C B B


Approach LOS

Average Queue (ft) 15 15 17 3 3 3 20 20 20 14 14 13


15.5 B



Movement LOS D D B E D C B A A B B A


Approach LOS

Average Queue (ft) 0 5 8 43 43 46 9 9 10 18 18 20


16.9 B



12th Army Navy


82.3 33.0 67.1 34.5

F C E C

77.5 19.4 28.1 112.8

E B C F

55/O. Joyce

- Joyce


29/Q. 12th & Hayes

12th Hayes


18.5 13.7 7.3 6.1

C B A A

36/S. 12th & Fern

12th Fern


49.1 33.2 7.6 0.0

D C A A

46/V. 12th & Eads

12th Eads


22.7 16.1 12.5 14.2

C B B B


20.7 56.1 7.9 13.0

C E A B





2 of 2



PM Peak Hour



Army Navy & Pentagon Mall 54 30.87 C 59.44 26.48 59.44

Army Navy & Hayes 28 50.93 D 51.09 42.92 50.32

Army Navy & Fern 35 49.42 D 49.27 59.95 48.44

Army Navy & Eads 34 108.71 F 109.52 70.48 107.19

Army Navy & 12th 27 209.65 F 209.90 63.32 207.70

Joyce 55 11.36 B 11.35 16.08 11.33

12th & Hayes 29 16.31 B 16.17 36.12 16.03

12th & Fern 36 26.23 C 26.34 19.31 26.13

12th & Eads 46 63.28 E 63.84 39.55 62.68



Movement LOS C C C E C B D E B E E D


Approach LOS

Average Queue (ft) 26 26 26 157 157 153 99 120 130 169 169 170


40.4 D



Movement LOS C C D E B A E N/A D D A A


Approach LOS

Average Queue (ft) 88 88 88 66 70 78 74 74 74 10 10 14


30.9 C



Movement LOS F D D F D A F D D E D B


Approach LOS

Average Queue (ft) 162 100 132 14 140 0 299 140 18 144 144 2


50.9 D



Movement LOS E C C F D D F E F F D B


Approach LOS

Average Queue (ft) 40 99 23 37 183 186 126 675 675 26 32 30


49.4 D


24.8 55.0 18.0

C C D B




Army Navy Eads


38.2 45.9 79.7 32.7

D D E C



Army Navy Fern


52.8 37.1 77.1 42.9

D D E D



Army Navy Hayes


25.6 30.5 44.4 57.3

C C D E


Entrance



33.1


Army Navy Joyce St


Intersection No

Total Traffic Delay


Ultimate Concept

PM Peak Hour

1 of 2



PM Peak Hour


Movement LOS F C B N/A F F F F F C D B


Approach LOS



108.7 F



Movement LOS F D B A F F E E E E A E


Approach LOS

Average Queue (ft) 43 43 69 1300 1300 1308 13 13 13 97 97 97


209.7 F



Movement LOS C - C C - A - A A C B -


Approach LOS

Average Queue (ft) 1 - 1 8 - 10 - 23 23 3 10 -


11.4 B



Movement LOS E D D E E C B A A A A A


Approach LOS

Average Queue (ft) 36 36 36 57 57 60 6 22 1 0 15 16


16.3 B



Movement LOS D C C B B B B B B C C D


Approach LOS

Average Queue (ft) 27 27 28 1 1 1 15 15 15 35 35 36


26.2 C



Movement LOS F C B E F D F F D D E B


Approach LOS

Average Queue (ft) 4 3 5 39 39 39 183 183 183 165 165 169


63.3 EIntersection Delay (sec/veh)

30.0 55.5 73.4 55.5

C E E E





46/V. 12th & Eads

12th Eads


31.6 12.8 12.5 33.9

C B B C

36/S. 12th & Fern

12th Fern


54.3 45.5 10.2 9.6

D D B A

29/Q. 12th & Hayes

12th Hayes


20.3 15.3 9.4 12.9

C C A B

55/O. Joyce

- Joyce


38.0 92.1 60.8 69.6

D F E E



12th Army Navy


71.9 29.4 180.5 109.9

E C F F

2 of 2

Documents

Army Navy Drive Supplemental Traffic Analysis Memorandum · Army Navy Drive Traffic Analysis Project #: 11834 Task 32 November 13, 2017 Page 2 Kittelson & Associates, Inc. Reston,