HomeMy WebLinkAboutfile from email sent by N. Janders on 3/4/2022 9:42am - ICA-NE44thStI-405 Renton to Bellevue – NE 44th Street
Intersection Control Analysis Report
FINAL Report
July 2018
WSDOT provides data in this report with the understanding under 23 U.S. Code § 148 and 23 U.S. Code § 409, safety data, reports, surveys, schedules, lists compiled or collected for the
purpose of identifying, evaluating, or planning the safety enhancement of potential crash sites,
hazardous roadway conditions, or railway-highway crossings are not subject to discovery or admitted into evidence in a Federal or State court proceeding or considered for other purposes
in any action for damages arising from any occurrence at a location mentioned or addressed in
such reports, surveys, schedules, lists, or data.
1 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
INTRODUCTION
Currently, I-405 between Renton and Bellevue experiences congestion due to high regional and local traffic demands in both directions for many hours of the day. The I-405 Renton to Bellevue project will
add a new lane in each direction of I-405, and couple that with the existing HOV lane to create a two-lane
express toll lane (ETL) system. This project is part of the I-405 long term vision for the corridor. As part of the Renton to Bellevue project, the NE 44th Street interchange will be reconstructed.
The purpose of the ICA is to evaluate the compatibility of different intersection control types with respect
to context, modal priority, design feasibility, and cost, while balancing operational needs. This analysis documents intersection traffic control and safety improvements associated with the NE 44th Street
interchange reconstruction for existing, opening year, and design year conditions. A comparison of the
alternatives considered is discussed and roundabout intersection control is recommended for the intersections in the vicinity of the NE 44th Street interchange.
PROJECT DESCRIPTION
The Renton to Bellevue Project area extends along I-405 for approximately 13.7 miles from the I-5
interchange (milepost MP 0.0) in Tukwila to the NE 6th interchange (MP 13.7) in Bellevue. The NE 44th Street interchange modifications include reconstructing the local road overpass at the interchange,
construction of a new direct access ramps for transit and ETL users in the I-405 median, reconstruct Lake Washington Boulevard between NE 44th Street and SE 76th Street, and realign the northbound on-ramp to I-405 to connect to Lake Washington Boulevard.
MODELING ASSUMPTIONS
The following assumptions were used in the modeling:
• Year of opening for this project is 2025 and the design year is 2045.
• Unsignalized and signalized intersections were modeled using Synchro version 9.1.912. Roundabouts were analyzed using Sidra version 6.1. Input settings in the Sidra model follow the WSDOT Sidra Policy Settings (November 2015). The environmental factor
was set to 1.1 for the year of opening and 1.0 for the horizon year.
• The LOS reported for signaled intersections represents the average control delay in
seconds per vehicle and is reported for the overall intersection. The LOS reported at one-way stop controlled (OWSC) and two-way stop controlled (TWSC) intersections is reported by the worst movement, typically a stop controlled, left turn movement.
• Crash history was collected for each intersection for the most recent five-year period, 2012-2016. Crashes are reported by crash type and severity and are reported in total
crashes over the five-year period.
• For all intersections, the design accommodated a WB-67 within the available pavement
and without encroaching into oncoming lanes. Therefore, a WB-67 is not precluded at
any intersection. At the NE 44th Street interchange the design vehicle is a Bus-45.
2 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Volume Forecasts
Existing intersection turning movement counts were collected on July 13, 2016 for all intersections during the AM and PM peak periods. Year 2025 and 2045 intersection volumes were developed based on PSRC
forecasts as well as local development details provided by the City of Renton and Sound Transit. The City of Renton has a permitted development west of the interchange that is assumed to be constructed by year 2025. Sound Transit has identified the NE 44th Street interchange southwest quadrant as the
representative location of a future 200-stall park and ride which is planned to be completed in year 2025
as well.
Transit Accommodations
King County Metro and Sound Transit have bus service through the study area. Where existing bus
service exists, the proposed intersection control modifications will not preclude buses from operating within each interchange area. Existing bus stops would be reconfigured or relocated close to their current
location under the Build alternatives. Metro has projected an increase in future bus use; however, no new
stop locations are planned.
Sound Transit will be implementing Bus Rapid Transit (BRT) along I-405 by year 2025. This service
will operate in the ETLs and will stop at the NE 44th Street ramps and continue on I-405.
Existing Conditions
Figure 1 shows the existing intersection control and channelization for the five study intersections at the NE 44th Street interchange. All intersections operate as two-way stop control (TWSC) except for the NE
44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd intersection, which currently
operates as all-way stop control (AWSC). The posted speed limit on NE 44th Street is 25 mph.
Figure 1 – Existing NE 44th Study Intersection Control and Channelization.
3 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Traffic Volumes
Average daily traffic in 2016 was approximately 12,200 vehicles per day. Turning movement volumes for
the AM and PM peak hours is provided in Appendix A.
Transit
King County Metro and Sound Transit have transit service that operates on I-405; however, bus stops and local transit service is not provided within the NE 44th Street interchange area.
Traffic Operations
Existing AM and PM peak hour traffic operations are summarized in Table 1. Detailed intersection approach LOS and delay are provided in Appendix B.
Both ramp terminal intersections currently operate with one or more approaches at LOS F in both the AM
and PM peak hours.
Table 1. Existing Intersection Peak Hour Operations
AM Peak Hour PM Peak Hour
Intersection LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 C 17.0 C 15.1
#24 - NE 44th Street and Seahawks Way2 C 19.2 C 18.4
#25 - NE 44th Street and I-405 Southbound Ramp
Terminal F >150 F 56.0
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd F 62.7 F 103.5
Delay reported in seconds/vehicle
For roundabout intersections, LOS and Delay is reported using signalized intersection LOS thresholds
For AWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
Crash History
Table 2 shows the total existing crash experience by severity and Table 3 shows the total existing crash
experience by crash type. Total crash history for the last five-year period (2012-2016) shows a total of 20
crashes (approximately 4 crashes/yr) at the NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd intersection and 15 crashes (approximately 3 crashes/yr) at the NE 44th Street and I-405
Southbound Ramp Terminal intersection. Of the fourteen reported injury crashes at the intersections, none
were a serious injury.
The most predominant crash type is sideswipe/angle, indicating vehicles were hit by opposing traffic
within the intersection. As these intersections are stop-controlled and operate poorly during both peak
hours, it is likely drivers are misjudging gaps and/or there are not enough gaps in the traffic stream. Crash reports also indicate driver distraction/inattention is a contributing factor.
4 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table 2. Existing Intersection Crash Experience by Severity
Severity - Total for 5 Years
ID Intersection Fatality Injury PDO Unknown Total
24 NE 44th Street and Seahawks Way 0 1 6 0 0
25 NE 44th Street and I-405 Southbound Ramp Terminal 0 8 7 0 15
27 NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd 0 5 14 1 20
Table 3. Existing Intersection Crash Experience by Crash Type
Type - Total for 5 Years
ID Intersection Rear-End Sideswipe/Angle Fixed Object Other Total
24 NE 44th Street and Seahawks Way 0 5 1 1 0
25 NE 44th Street and I-405 Southbound Ramp Terminal 1 14 0 0 15
27 NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd 3 17 0 0 20
No Build and Build Conditions
No Build
By 2025, local development mitigation would add capacity to the two ramp terminal intersections on NE
44th Street and the intersection of NE 44th Street and Seahawks Way by providing traffic signals. These three intersections will also have additional minor channelization improvements. Figure 2 shows the
assumed No Build intersection control and channelization.
Traffic Volumes
Year 2025 and Year 2045 AM and PM peak hour intersection turning movement forecasts are provided in Appendix A. The NE 44th Street ADT is expected to increase to 15,900 vehicles per day in 2025 and
16,700 in 2045.
Three specific background developments were assumed to be completed by the year 2025:
• The Port Quendall Terminals development would be located on the north side of NE 44th Street
between N 43rd Street and Seahawks Way
• The Hawk’s Landing development would be located on the south side of NE 44th Street between
the SB on-ramp and N 43rd Street.
• The Kennydale Mixed-Use development would be located on the east side of Lake Washington
Blvd.
5 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Figure 2. NE 44th Study Intersection Control and Channelization: No Build
Transit
No change in transit operations is assumed under the No Build alternative.
Traffic Operations
Year 2025 No Build peak hour operations are summarized in Table 4 and Year 2045 No Build peak hour operations are summarized in Table 5. Detailed intersection approach LOS and delay are provided in
Appendix B.
By 2025, the additional capacity and signalization of the two ramp terminal intersections at NE 44th Street and the intersection of NE 44th Street and Seahawks Way will result in better operations than
existing (2016) conditions.
Build Alternatives
Alternatives Considered
Several interchanges types were developed, however, the configuration shown in Figure 4 was selected.
Two intersection control alternatives were analyzed for this project, traffic signals and roundabouts.
Design elements common to both alternatives include:
• Direct access ramps to and from the Express Toll Lanes
• The northbound loop on-ramp was removed. The loop ramp could not remain because design
criteria could not be met with a wider I-405 mainline and direct access ramps (i.e. the radius
would be too tight due to less width).
6 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
• The northbound on-ramp relocated to Lake Washington Blvd.
• The intersection control at NE 44th Street and N 43rd Street is assumed to be a roundabout The
NE 44th Street and Seahawks Way intersection is also assumed to be converted into a right-in,
right-out. All left turning movements are assumed to shift to the NE 44th Street and N 43rd
Street intersection. However, construction of the roundabout and access modifications to
Seahawks Way would occur with the Hawks Landing and/or Port Quendall development and is
not considered as part of the Renton-to-Bellevue project.
A description of each alternative is provided below.
Signals
New traffic signals would be installed at the NE 44th Street and I-405 Direct Access Ramps intersection
and at the Lake Washington Blvd and Northbound I-405 On-ramp intersection. The traffic signals, assumed to be constructed prior to 2025, at the NE 44th Street and I-405 Southbound Ramp Terminal intersection and at the NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd. would
be modified to accommodate additional through and turn lanes. The Signal Alternative channelization is shown in Figure 3. The Signal Alternative is considered with the fact of its public familiarity, and
coordination capability in congestion conditions.
Roundabouts
Roundabouts would be provided at all ramp terminal intersections. A total of four multilane roundabouts
would be along NE 44th Street and an additional single lane roundabout would be along Lake
Washington Blvd. The Roundabout Alternative channelization is shown in Figure 4. Roundabouts are employed as an improvement option with the consideration of the fact that it encourages low travel speeds
and continuous flow of traffic, especially during the off-peak period, and works well with pedestrian
movements.
Environmental Impacts
No contamination above MTCA cleanup levels is detected within the NE 44th Interchange area, except at the former May Creek stream bed. This contaminated spot is located 25 feet from the southwest radius of Seahawks Way and NE 44th Street, but the depth that the contamination is not expected to be disturbed
by construction activities. In the signalized intersection concept, the pavement width would be greater than the roundabout by a few feet due to the eastbound right turn pocket to Seahawks Way, but will still be within the existing interchange area and existing WSDOT right-of-way. Wetland Buffer impacts would
be greater with the signalized alternative due to the wetland buffer north of NE 44th Street, between Seahawks Way and I-405 southbound off ramp.
Traffic Volumes
Year 2025 and Year 2045 AM and PM peak hour intersection turning movement forecasts are provided in Appendix B. The NE 44th Street ADT is expected to be to 16,900 vehicles per day in 2025 and 18,300 in 2045 under the Build condition, slightly higher than the No Build condition.
7 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Transit
As part of the BRT service, a freeway station will be built at the NE 44th Street interchange. Transit stops
are proposed to be located on the south leg of the NE 44th Street and I-405 Direct Access Ramps
intersection. BRT service would operate through the intersection and resume operations in the I-405 ETL lanes. The BRT service is expected to operate with 10-minutes headways throughout the day. Two-way
local bus service operated by King County Metro is also assumed to operate along NE 44th Street with
30-minute headways during the peak periods in concert with I-405 BRT service.
Traffic Operations
Year 2025 Build Alternative peak hour operations are summarized in Table 4 and Year 2045 Build
Alternative peak hour operations are summarized in Table 5. Detailed intersection approach LOS and delay are provided in Appendix B. All intersections under both Build alternatives will operate at LOS C
or better.
Table 4. Year 2025 No Build and Build Alternatives Peak Hour Operations
No Build Build - Signals Build - Roundabouts
Intersection LOS Delay LOS Delay LOS Delay
AM Peak Hour
#23 - NE 44th Street and N 43rd St1 B 13.2 A 6.2 A 6.2
#24 - NE 44th Street and Seahawks Way2 B 19.3 B 15.0 B 15.0
#25 - NE 44th Street and I-405 Southbound Ramp Terminal D 42.1 B 12.9 A 4.6
#26 - NE 44th Street and I-405 DA Ramp N/A N/A A 9.5 A 5.4
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd B 15.9 C 21.5 A 5.9
#28 - I-405 NB On Ramp and Lake Washington Blvd NE N/A N/A B 15.9 A 8.4
PM Peak Hour
#23 - NE 44th Street and N 43rd St1 C 15.8 A 5.5 A 5.5
#24 - NE 44th Street and Seahawks Way2 A 8.3 B 14.7 B 14.7
#25 - NE 44th Street and I-405 Southbound Ramp Terminal B 15.1 B 10.8 A 4.2
#26 - NE 44th Street and I-405 DA Ramp N/A N/A B 12.2 A 4.7
#27 - NE 44th Street and I-405 Northbound Ramp
Terminals/Lake Wash. Blvd B 15.7 C 27.2 A 6.1
#28 - I-405 NB On Ramp and Lake Washington Blvd NE N/A N/A B 11.8 A 7.8
Delay reported in seconds/vehicle
For roundabout intersections, LOS and Delay is reported using signalized intersection LOS thresholds
For AWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
1Unsignalized in Existing and No Build Alternative, Roundabout Control in Build alternatives
2Signalized in No Build Alternative, OWSC in Existing and Build alternatives
8 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table 5. Year 2045 No Build and Build Alternatives Intersection Peak Hour Operations
No Build Build - Signals Build - Roundabouts
Intersection LOS Delay LOS Delay LOS Delay
AM Peak Hour
#23 - NE 44th Street and N 43rd St1 B 13.6 A 5.8 A 5.8
#24 - NE 44th Street and Seahawks Way2 C 20.0 C 15.5 B 15.5
#25 - NE 44th Street and I-405 Southbound Ramp Terminal D 53.8 B 14.6 A 4.5
#26 - NE 44th Street and I-405 DA Ramp N/A N/A B 10.5 A 5.2
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd B 17.7 C 23.3 A 5.8
#28 - I-405 NB On Ramp and Lake Washington Blvd NE N/A N/A B 16.1 A 8.3
PM Peak Hour
#23 - NE 44th Street and N 43rd St1 B 11.8 A 5.2 A 5.2
#24 - NE 44th Street and Seahawks Way2 A 8.8 C 15.8 C 15.8
#25 - NE 44th Street and I-405 Southbound Ramp Terminal B 15.7 B 11.8 A 4.0
#26 - NE 44th Street and I-405 DA Ramp N/A N/A B 16.5 A 4.8
#27 - NE 44th Street and I-405 Northbound Ramp
Terminals/Lake Wash. Blvd B 16.9 C 27.5 A 5.9
#28 - I-405 NB On Ramp and Lake Washington Blvd NE N/A N/A B 13.1 A 6.9
Delay reported in seconds/vehicle
For roundabout intersections, LOS and Delay is reported using signalized intersection LOS thresholds
For AWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
1Unsignalized in No Build Alternative, Roundabout Control in Build alternatives
2Signalized in No Build Alternative, OWSC in Build alternatives
In addition to intersection LOS and delay, 95th percentile queue lengths for both build alternatives are
summarized in Appendix C for Year 2025 and Year 2045, respectively.
With the signal alternative, queueing impacts will occur between closely spaced intersections, as well as on the approach to the interchanges. Especially during the AM peak period, the eastbound and westbound
movement at the NE 44th/ I-405 Southbound ramp terminal intersection will overflow to upstream intersections. However, queues are expected to be contained within available storage with the roundabout alternative. With the roundabout alternative, only four lanes are required on NE 44th St across I-405,
whereas, with the signal alternative, six lanes would be needed.
1 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Figure 3. NE 44th Study Intersection Control and Channelization-Signal Alternative
2 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Figure 4. NE 44th Study Intersection Control and Channelization-Roundabouts Alternative
1 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Safety
WSDOT maintains a crash modification factor (CMF) short list for the selection of appropriate CMFs. By
converting a signal controlled intersection to roundabout in an urban environment, the expected collision
reduction factors are as follows:
Multi Lane Roundabout:
All crashes = 0.79 (WSDOT Reference Number WC – 4252)*
Fatal and injury crashes = 0.34 (WSDOT Reference Number WC – 4253)
Single Lane Roundabout:
All crashes = 0.74 (WSDOT Reference Number WC – 4256)*
Fatal and injury crashes = 0.45 (WSDOT Reference Number WC – 4257)
*WSDOT recommends using a CMF = 1.0 for intersections with total entering volumes greater than 18,000
The multilane roundabouts along NE 44th Street are expected to have total entering volume greater than
18,000 vehicles per day, therefore, an overall reduction in total crashes is not expected and an increase in
property damage only crashes may occur. However, a 66 percent reduction in fatal and injury related crashes is expected when compared to a signalized option. The single lane roundabout at the I-405
Northbound On-ramp and Lake Washington Blvd NE intersection is expected to have less than 18,000
total daily entering vehicles; therefore, 21 percent fewer total crashes and 55 percent fewer fatal and injury crashes are expected compared to the signalized option. While the multilane roundabout CMF’s
provided above do not differentiate if one or more roundabout approaches have greater than one lane, the
roundabouts along NE 44th Street were designed to minimize the number of multilane entry and multi-lane circulating conflicts.
With the proposed design of these roundabouts, vehicles will travel at lower speeds (15-20 mph)
compared to a signalized option. Furthermore, the number of conflict points will be reduced for both vehicles and pedestrians.
With the Roundabout Alternative, bicyclists will have two choices to traverse through the roundabout intersections. Bicycles will be allowed to exit the roadway via bicycle access ramps and use sidewalks or bicycles could continue along the roadway and enter the roundabouts in the traffic lane.
There have been no reported pedestrian or bicycle collisions at any of the study intersections. However, due to the location of the I-405 BRT bus stops, the level of nonmotorized activity is expected to increase
under both options. With the signalized option, pedestrians will be able to cross at marked crosswalk
locations. With the roundabout alternative, pedestrians will be able to cross at marked crosswalks one approach leg of the roundabout at a time with a refuge island provided between the entering and exiting
roundabout lanes.
2 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Summary and Recommendation
No Build Alternative
The No Build Alternative study intersections operate at LOS D or better, with the exception of the NE
44th Street and I-405 Southbound Ramp Terminal intersection, which will operate at LOS F by the Year 2045 in the AM Peak period. The No Build Alternative is not compatible with the Renton-to-Bellevue project as major bridge reconstruction is required and ETL direct access to the NE 44th Street interchange
is desirable.
Signal Alternative
The Signal Alternative will operate with acceptable LOS at all study intersections (LOS C or better);
however, queuing impacts will occur between the closely spaced intersections. This alternative will have
a higher collision risk compared with the No Build alternative as overall interchange traffic volumes will increase and two new signalized intersections are assumed with the alternative, increasing the number of
potential conflict points within the interchange area.
Roundabout Alternative
The Roundabout Alternative operates at LOS A in both the AM and PM peak periods at all roundabout
intersections. Vehicle queues are expected to be contained within available storage. With the Roundabout
Alternative, only four lanes are required across I-405; whereas with the Signal Alternative, six lanes would be required. At all ramp terminal intersections, injury and fatal crashes are expected to be at least
55 percent lower than the No Build and Signal alternatives.
Recommendation
Based on safety performance, traffic operations, and project footprint impacts, the Roundabout
Alternative best meets the project need.
A-1 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
APPENDIX A – EXISTING, 2025 AND 2045 NO BUILD AND BUILD INTERSECTION VOLUMES
A-2 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Existing AM Peak Hour
Existing PM Peak Hour
Figure A1. Existing Peak Hour Turning Movements
20 5 30 50 140 0 375 245
5 30 45
145 0 20 145 150 150 5 0 25 145 175 175 70 0 70 105 470 470 300 35 40 160 490
0 365 285
0 20 145
680 680 700 700 675 0 0 0 700 700 680 750 750 125 10 55 105 270
5 20 480
0 0 5 0 385 0 800 170NE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 NB RampsNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th St23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 27 Lake Washington Blvd
20 20 55 50 240 0 600 365
20 35 50
480 0 20 480 500 500 15 0 40 485 525 525 170 20 50 355 690 690 520 15 65 150 275
5 335 75
0 15 95
215 215 235 235 220 0 0 5 265 265 240 290 290 110 20 220 140 315
0 25 85
0 0 5 5 380 0 175 380
23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 27 Lake Washington Blvd
NE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 NB RampsNE 44th St
A-3 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Year 2025 AM Peak Hour
Year 2025 PM Peak Hour
Figure A2. Year 2025 No Build Peak Hour Turning Movements
75 20 65 65 140 0 430 295
5 40 50
240 50 0 25 190 195 195 10 0 55 160 220 220 70 0 70 150 540 540 350 35 45 180 515
0 20 390 285
15 25 185
745 730 0 0 0 755 755 700 25 0 20 775 775 755 825 825 160 10 60 120 325
0 30 20 480
0 0 50 45 410 0 800 190NE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 NB RampsNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th St23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 27 Lake Washington Blvd
55 75 80 85 265 0 715 430
25 65 55
565 30 0 25 535 560 560 20 0 60 530 615 615 ##25 55 430 830 830 625 20 70 185 330
0 20 400 90
50 20 135
325 275 0 0 0 300 300 255 10 0 25 340 340 310 365 365 130 20 240 150 350
0 25 30 100
0 0 45 35 455 0 210 410
23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 27 ake Washington Blv
NE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 NB RampsNE 44th St
A-4 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Year 2045 AM Peak Hour
Year 2045 PM Peak Hour
Figure A3. Year 2045 No Build Peak Hour Turning Movements
75 20 65 65 140 0 465 320
5 40 60
250 50 0 25 200 205 205 10 0 55 170 230 230 70 0 70 160 585 585 380 35 50 195 545
0 20 425 290
15 25 195
770 755 0 0 0 780 780 725 25 0 20 800 800 780 850 850 170 10 65 130 350
0 30 20 485
0 0 50 45 445 0 810 205NE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 NB RampsNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th St23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 27 ake Washington Blv
30 75 110 90 280 0 755 440
25 70 60
610 30 0 0 580 605 605 20 0 90 575 665 665 195 25 60 470 870 870 655 20 80 195 345
0 20 400 90
50 20 140
340 290 0 0 0 290 290 245 10 0 25 360 360 330 390 390 145 20 240 150 375
0 25 30 105
0 0 45 35 455 0 215 410
23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 27 ake Washington Blv
NE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 NB RampsNE 44th St
A-5 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Year 2025 AM Peak Hour
Year 2025 PM Peak Hour
Figure A4. Year 2025 Build Peak Hour Turning Movements
452 403
35
510 13 395 45 13 133
85
0
0 0 485 368 37 82
0
480 890
385 55 10 110 130 0 110 510 480 890
15 110 95 259
261 50 0 335 186 335 335 10 0 0 325 436 436 78 0 52 358 626 626 83 0 28 505 752 752 435 0 45 287 546
134 0 268 152 0
40 0 415 571
822 757 25 0 13 1,105 1,105 1098 0 0 117 1,215 1,215 1133 1,185 1,185 722 38 0 112 862 862 291 30 60 130 466
25 7 82 48 0
159 38 7 117 350 0 200 150 0 220
ake Washington Blv
I-405 NB On RampRetail Drivewayake Washington Blv
23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 26 I-405 ETL Ramp 27 ake Washington Blv
28
NE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 ETL Ramp I-405 NB RampsNE 44th St766 498
36
205 10 703 53 10 113
67
0 185 462 98 151
770 745
253 120 20 345 310 0 240 150 770 745
50 345 35 123
587 30 0 223 533 703 703 20 0 0 683 1,033 1,033 212 20 78 821 1,081 1,081 174 0 66 869 1,092 1,092 700 0 70 372 495
120 5 260 188 0
70 0 115 402
313 223 24 0 14 460 460 455 0 0 135 590 590 500 578 578 396 38 0 172 634 634 232 20 220 140 442
20 5 90 67 0
140 38 10 135 370 0 255 210 0 380NE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 ETL Ramp I-405 NB RampsNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th Stake Washington Blv
I-405 NB On RampRetail Drivewayake Washington Blv
23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 26 I-405 ETL Ramp 27 ake Washington Blv
28
A-6 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Year 2045 AM Peak Hour
Year 2045 PM Peak Hour
Figure A5. Year 2045 Build Peak Hour Turning Movements
487 465
35
570 13 430 45 13 133
85
0
0 0 545 430 40 85
0
515 1,015
385 54 10 110 135 0 120 540 515 1,015
14 110 100 318
272 50 0 335 197 346 346 10 0 0 336 446 446 83 0 52 363 663 663 90 0 30 535 783 783 465 0 50 308 626
134 0 300 148 0
40 0 440 627
863 798 25 0 13 1,146 1,146 1139 0 0 122 1,261 1,261 1166 1,218 1,218 731 38 0 177 938 938 311 10 70 140 501
25 7 95 47 0
159 38 7 122 395 0 195 215 0 220NE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 ETL Ramp I-405 NB RampsNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StLake Washington Blvd
I-405 NB On RampRetail DrivewayLk Wash Blvd
23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 26 I-405 ETL Ramp 27 Lk Wash Blvd
28
836 563
36
210 10 773 53 10 113
67
0 190 527 98 151
840 815
253 119 20 350 310 0 320 160 840 815
49 350 38 132
656 30 0 223 602 770 770 20 0 0 750 1,106 1,106 207 25 78 899 1,191 1,191 208 0 113 936 1,186 1,186 760 0 80 406 538
120 5 292 212 0
70 0 123 428
367 277 24 0 14 514 514 504 0 0 128 633 627 529 607 607 411 47 0 183 707 707 279 20 255 160 519
20 10 98 73 0
140 38 15 128 415 0 285 230 0 435
ake Washington Blv
I-405 NB On RampRetail Drivewayake Washington Blv
23 N 43rd St 24 Seahawks Way 25 I-405 SB Off Ramp 26 I-405 ETL Ramp 27 ake Washington Blv
28
NE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StNE 44th StN 43rd St Seahawks Way I-405 SB On Ramp I-405 ETL Ramp I-405 NB RampsNE 44th St
B-1 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
APPENDIX B – EXISTING, 2025 AND 2045 NO BUILD AND BUILD LOS AND DELAY
B-2 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table B1. Existing AM and PM Peak Hour Traffic Operations
EB WB NB SB Overall
Intersection LOS Delay LOS Delay LOS Delay LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 A/(A) <1/(<1) A/(A) <1/(<1) - - C/(C) 17.0/(15.1) C/(C) 17.0/(15.1)
#24 - NE 44th Street and Seahawks Way1 A/(A) 7.6/(8.6) A/(A) <1/(<1) A/(A) <1/(9.5) C/(C) 19.2/(18.4) C/(C) 19.2/(18.4)
#25 - NE 44th Street and I-405
Southbound Ramp Terminal1 A/(A) <1/(<1) B/(A) 12.6/(9.0) - - F/(F) >150/(56.0) F/(F) >150/(56.0)
#27 - NE 44th Street and I-405 Northbound Ramp
Terminals/Lake Wash. Blvd2
F/(C) 100.1/(23.7) D/(C) 28.2/(17.
1) C/(F) 19.8/(55.1) F/(F) 52.3/(>150) F/(F) 62.7/(103.5)
Delay reported in seconds/vehicle
XXX/(XXX) = AM/(PM)
1For OWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
2For AWSC intersection, LOS and delay uses HCM 2010 methodology
B-3 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table B2. Year 2025 No Build AM and PM Peak Hour Traffic Operations
EB WB NB SB Overall
Intersection LOS Delay LOS Delay LOS Delay LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 A/(A) <1/(<1) A/(A) <1/(<1) - - B/(C) 13.2/(15.8) B/(C) 13.2/(15.8)
#24 - NE 44th Street and Seahawks Way1 C/(A) 20.7/(8.1) B/(A) 14.8/(6.7) B/(B) 18.0/(16.8) B/(B) 18.5/(18.0) B/(A) 19.3/(8.3)
#25 - NE 44th Street and I-405
Southbound Ramp Terminal C/(C) 29.1/(20.2) E/(B) 64.6/(12.3) - - C/(B) 26.9/(17.6) D/(B) 42.1/(15.1)
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake
Wash. Blvd
A/(A) 2.7/(5.4) B/(B) 12.7/(16.4) C/(B) 29.9/(18.3) D/(B) 39.0/(19.2) B/(B) 15.9/(15.7)
Delay reported in seconds/vehicle
XXX/(XXX) = AM/(PM)
1For OWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
2For AWSC intersection, LOS and delay uses HCM 2010 methodology
B-4 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table B3. Year 2045 No Build AM and PM Peak Hour Traffic Operations
EB WB NB SB Overall
Intersection LOS Delay LOS Delay LOS Delay LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 A/(A) <1/(1.8) A/(A) <1/(<1) - - B/(B) 13.6/(11.8) B/(B) 13.6/(11.8)
#24 - NE 44th Street and Seahawks Way1 C/(A) 21.7/(8.0) B/(A) 15.1/(7.1) B/(B) 18.0/(16.8) B/(B) 18.5/(19.0) C/(A) 20.0/(8.8)
#25 - NE 44th Street and I-405
Southbound Ramp Terminal C/(C) 32.4/(23.0) F/(B) 89.5/(12.1) - - C/(B) 26.9/(17.7) D/(B) 53.8/(15.7)
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash.
Blvd
A/(A) 2.8/(5.7) B/(B) 13.4/(16.6) C/(B) 30.6/(18.3) D/(C) 44.2/(22.1) B/(B) 17.7/(16.9)
Delay reported in seconds/vehicle
XXX/(XXX) = AM/(PM)
1For OWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
2For AWSC intersection, LOS and delay uses HCM 2010 methodology
B-5 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table B4. Year 2025 Build AM and PM Peak Hour Traffic Operations- Build Signalized Alternative
EB WB NB SB Overall
Intersection LOS Delay LOS Delay LOS Delay LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 A/(A) 5.5/(4.9) A/(A) 4.4/(3.5) A/(A) 8.9/(7.0) A/(B) 8.9/(11.4) A/(A) 6.2/(5.5)
#24 - NE 44th Street and Seahawks Way2 A/(A) <1/(<1) A/(A) <1/(<1) B/(B) 15.0/(10.7) B/(B) 10.3/(14.7) B/(B) 15.0/(14.7)
#25 - NE 44th Street and I-405 Southbound
Ramp Terminal B/(A) 12.0/(7.9) A/(A) 8.3/(3.6) - - D/(D) 43.0/(41.4) B/(B) 12.9/(10.8)
#26 - NE 44th Street and I-405 DA Ramp A/(A) 5.5/(5.2) A/(A) 4.3/(3.8) D/(D) 42.9/(41.4) D/(D) 42.7/(42.0) A/(B) 9.5/(12.2)
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd C/(C) 23.1/(32.8) B/(C) 18.8/(25.4) D/(D) 45.6/(52.7) B/(B) 10.8/(11.3) C/(C) 21.5/(27.2)
#28 - I-405 NB On Ramp and Lake
Washington Blvd NE - - D/(D) 47.6/(45.5) A/(A) 7.4/(6.4) C/(B) 23.3/(12.1) B/(B) 15.9/(11.8)
Delay reported in seconds/vehicle
XXX/(XXX) = AM/(PM)
1For roundabout intersection, LOS and Delay is reported for each approach using HCM 2000 methodology
2For OWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
B-6 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table B5. Year 2045 Build AM and PM Peak Hour Traffic Operations- Build Signalized Alternative
EB WB NB SB Overall
Intersection LOS Delay LOS Delay LOS Delay LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 A/(A) 5.1/(4.6) A/(A) 4.2/(3.3) A/(A) 8.4/(6.8) A/(B) 8.5/(11.3) A/(A) 5.8/(5.2)
#24 - NE 44th Street and Seahawks Way2 A/(A) <1/(<1) A/(A) <1/(<1) C/(B) 15.5/(10.9) B/(C) 10.4/(15.8) C/(C) 15.5/(15.8)
#25 - NE 44th Street and I-405 Southbound
Ramp Terminal B/(A) 13.8/(8.9) B/(A) 10.2/(5.5) - - D/(D) 43.0/(41.8) B/(B) 14.6/(11.8)
#26 - NE 44th Street and I-405 DA Ramp A/(B) 5.6/(13.0) A/(B) 4.2/(12.2) D/(C) 42.8/(28.4) D/(C) 42.6/(30.3) B/(B) 10.5/(16.5)
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd C/(C) 25.0/(30.6) C/(C) 24.3/(30.4) D/(D) 41.0/(47.7) B/(B) 11.5/(12.5) C/(C) 23.3/(27.5)
#28 - I-405 NB On Ramp and Lake
Washington Blvd NE - - D/(D) 47.8/(45.5) A/(A) 7.3/(7.7) C/(B) 25.9/(14.0) B/(B) 16.1/(13.1)
Delay reported in seconds/vehicle
XXX/(XXX) = AM/(PM)
1For roundabout intersection, LOS and Delay is reported for each approach using HCM 2000 methodology
2For OWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
B-7 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table B6. Year 2025 Build AM and PM Peak Hour Traffic Operations- Build Roundabout Alternative
EB WB NB SB Overall
Intersection LOS Delay LOS Delay LOS Delay LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 A/(A) 5.5/(4.9) A/(A) 4.4/(3.5) A/(A) 8.9/(7.0) A/(B) 8.9/(11.4) A/(A) 6.2/(5.5)
#24 - NE 44th Street and Seahawks Way2 A/(A) <1/(<1) A/(A) <1/(<1) B/(B) 15.0/(10.7) B/(B) 10.3/(14.7) B/(B) 15.0/(14.7)
#25 - NE 44th Street and I-405 Southbound Ramp Terminal1 A/(A) 4.7/(4.2) A/(A) 3.9/(3.1) - - A/(A) 6.3/(8.1) A/(A) 4.6/(4.2)
#26 - NE 44th Street and I-405 DA Ramp1 A/(A) 4.7/(4.1) A/(A) 5.8(4.0) A/(A) 7.6/(5.7) A/(A) 6.3/(8.2) A/(A) 5.4/(4.7)
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd1 A/(A) 5.8/(5.7) A/(A) 6.9/(6.4) A/(A) 7.0/(6.5) A/(A) 4.6/(6.2) A/(A) 5.9/(6.1)
#28 - I-405 NB On Ramp and Lake Washington Blvd NE1 - - B/(A) 12.9/(10.0) A/(A) 6.0/(4.6) B/(B) 12.0/(10.6) A/(A) 8.4/(7.8)
Delay reported in seconds/vehicle
XXX/(XXX) = AM/(PM)
1For roundabout intersection, LOS and Delay is reported for each approach using HCM 2000 methodology
2For OWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
B-8 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table B7. Year 2045 Build AM and PM Peak Hour Traffic Operations- Build Roundabout Alternative
EB WB NB SB Overall
Intersection LOS Delay LOS Delay LOS Delay LOS Delay LOS Delay
#23 - NE 44th Street and N 43rd St1 A/(A) 5.1/(4.6) A/(A) 4.2/(3.3) A/(A) 8.4/(6.8) A/(B) 8.5/(11.3) A/(A) 5.8/(5.2)
#24 - NE 44th Street and Seahawks Way2 A/(A) <1/(<1) A/(A) <1/(<1) C/(B) 15.5/(10.9) B/(C) 10.4/(15.8) C/(C) 15.5/(15.8)
#25 - NE 44th Street and I-405 Southbound
Ramp Terminal1 A/(A) 4.6/(4.2) A/(A) 4.0/(3.1) - - A/(A) 6.0/(7.3) A/(A) 4.5/(4.0)
#26 - NE 44th Street and I-405 DA Ramp1 A/(A) 4.5/(4.3) A/(A) 5.6/(4.0) A/(A) 6.9/(5.6) A/(A) 5.8/(8.5) A/(A) 5.2/(4.8)
#27 - NE 44th Street and I-405 Northbound Ramp Terminals/Lake Wash. Blvd1 A/(A) 5.8/(5.5) A/(A) 6.9/(6.5) A/(A) 6.1/(6.2) A/(A) 4.4/(5.7) A/(A) 5.8/(5.9)
#28 - I-405 NB On Ramp and Lake
Washington Blvd NE1 - - B/(A) 13.9/(9.9) A/(A) 5.9/(4.4) B/(A) 11.8/(8.9) A/(A) 8.3/(6.9)
Delay reported in seconds/vehicle
XXX/(XXX) = AM/(PM)
1For roundabout intersection, LOS and Delay is reported for each approach using HCM 2000 methodology
2For OWSC and TWSC intersections, LOS and delay is reported for the worst movement using HCM 2000 methodology
C-1 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
APPENDIX C –2025 AND 2045 BUILD 95TH PERCENTILE QUEUE RESULTS
C-2 I-405 Renton-to-Bellevue Intersection Control Analysis
Table C1. 95th Percentile Queue for Year 2025 Build Alternatives
EB WB NB SB EB WB NB SB
#23 - NE 44th Street and N 43rd St1 100 50 <25 75 100 50 <25 75
#24 - NE 44th Street and Seahawks Way2 <25 <25 <25 <25 <25 <25 <25 <25
#25 - NE 44th Street and I-405 Southbound Ramp Terminal 425 225 75 100 <25 25
#26 - NE 44th Street and I-405 DA Ramp 150 100 75 50 100 75 50 25
#27 - NE 44th Street and I-405 Northbound
Ramp Terminals/Lake Wash. Blvd 175 150 125 m75 100 75 50 75
#28 - I-405 NB On Ramp and Lake Washington
Blvd NE 150 275 300 50 350 175
#23 - NE 44th Street and N 43rd St1 <25 100 <25 75 <25 100 <25 75
#24 - NE 44th Street and Seahawks Way2 <25 <25 <25 <25 <25 <25 <25 <25
#25 - NE 44th Street and I-405 Southbound Ramp Terminal 150 125 125 50 <25 50
#26 - NE 44th Street and I-405 DA Ramp 50 100 75 100 50 75 50 50
#27 - NE 44th Street and I-405 Northbound
Ramp Terminals/Lake Wash. Blvd #200 175 300 m75 50 50 75 150
#28 - I-405 NB On Ramp and Lake Washington
Blvd NE 125 m100 375 50 225 325
# 95th percentile volume exceeds capacity, queue may be longer. Queue shown is maximum after two cycles
m Volume for 95th percentile queue is metered by upstream signal
Intersection Build - Signals Build - Roundabouts
AM Peak Hour
PM Peak Hour
C-3 I-405 Renton-to-Bellevue – NE 44th Street Intersection Control Analysis
Table C2. 95th Percentile Queue for Year 2045 Build Alternatives
EB WB NB SB EB WB NB SB
#23 - NE 44th Street and N 43rd St1 100 50 <25 75 100 50 <25 75
#24 - NE 44th Street and Seahawks Way2 <25 <25 50 <25 <25 <25 50 <25
#25 - NE 44th Street and I-405 Southbound Ramp Terminal 475 275 75 100 <25 <25
#26 - NE 44th Street and I-405 DA Ramp 150 100 75 50 100 75 50 <25
#27 - NE 44th Street and I-405 Northbound
Ramp Terminals/Lake Wash. Blvd 225 175 150 m75 100 75 50 75
#28 - I-405 NB On Ramp and Lake Washington
Blvd NE 150 300 325 75 400 175
#23 - NE 44th Street and N 43rd St1 <25 100 <25 75 <25 100 <25 75
#24 - NE 44th Street and Seahawks Way2 <25 <25 <25 <25 <25 <25 <25 <25
#25 - NE 44th Street and I-405 Southbound Ramp Terminal 175 125 125 50 <25 50
#26 - NE 44th Street and I-405 DA Ramp 50 250 75 125 50 100 50 75
#27 - NE 44th Street and I-405 Northbound
Ramp Terminals/Lake Wash. Blvd #150 200 #350 m100 50 75 75 150
#28 - I-405 NB On Ramp and Lake Washington
Blvd NE 125 150 450 25 200 300
# 95th percentile volume exceeds capacity, queue may be longer. Queue shown is maximum after two cycles
m Volume for 95th percentile queue is metered by upstream signal
Intersection Build - Signals Build - Roundabouts
AM Peak Hour
PM Peak Hour