SR 104/Paradise Bay-Shine Road – Intersection Safety Improvements
Intersection Control Evaluation

Background and Project Needs
SR 104 is functionally classified as a rural-principal arterial. It is a limited access, partially
controlled, one lane in each direction. This intersection is the first intersection west of the Hood
Canal Bridge and is subject to long platoons for traffic during a bridge opening. This intersection
is in Jefferson County, has rolling terrain and is an NHS route. The posted speed within the
project limits is 40 mph. SR 104 had a 2017 AADT of 17,800 with about 7.3% trucks.
This project is categorized as an I-2 Safety Improvement (Collision Reduction) project. The
intersection of SR 104/Shine Road is an Intersection Analysis Location (IAL) for the year 2016.
Ninety percent of the 26 total crashes (2009 – 2015 crash history) at this intersection were
entering at angle type crashes from Paradise Road. This project will provide improved
intersection control, which has the potential to reduce number and severity of crashes.

This is a 4-leg intersection, about 800 ft. west of the west end of the Hood Canal Floating
Bridge. In the westbound direction, a climbing lane begins just past the intersection. There is
left-turn channelization on mainline for both directions of travel. There is a right-turn lane for
the westbound direction that serves the Paradise Bay Rd. There is no channelization on either

 of the minor legs. The vertical grade from the Hood Canal Bridge approaching this intersection
is around an incline of 5%, and the 85th percentile speeds are around 45 mph.
This intersection met signal warrants based on a 2005 count.
There are times when SR 104 is closed for bridge openings. Given the close proximity of the
Hood Canal Bridge, at these times eastbound traffic will often queue well to the west of this
intersection. After the bridge is open to traffic, there are often times large platoons of traffic
heading both directions.

Alternatives
Given the safety performance of the existing minor-street stop control, maintaining the existing
control is not considered as an alternative for the project. A single-lane roundabout and
signalized intersection were evaluated as part of this analysis. SIDRA was used for the
roundabout analysis and Synchro was used for the signal analysis. Please refer to appendices
for SIDRA and Synchro reports.
Intersection Leg
SR 104 (West)
SR 104 (East)
Shine Road
Paradise Bay RD
Overall I/S

Existing 2018 PM Peak (PM was critical peak*)
Single-Lane Roundabout
Signalized Intersection
Level of Service
Ave Delay (s)
Level of Service
Ave Delay (s)
A
8.8
B
19.7
A
6.1
C
22.9
A
5.1
C
21.6
A
9.6
B
19.5
A
6.4
C
20.9

*does not represent platoon from bridge opening

Feasibility
Both the signalized intersection and the single-lane roundabout are feasible alternatives.
Below, we will discuss the advantages and disadvantages of each.
Signalized Intersection – The signalized intersection will likely have a smaller footprint than that
of a roundabout, and therefore have minimal to no right-of-way needs. SR 104/Paradise BayShine RD intersection is on a curve and has a downward sloping profile (east-west direction).
One concern is the potential for rear-ends generated by a stopped queue from the signal.
Another safety concern with a signal is the potential for red light running.

Single-Lane Roundabout – Per the operational analysis above, the roundabout out-performed
the signalized intersection during the PM peak hour. During off-peak hours, it is expected that
the roundabout would also out-perform the signal because of the low delay for all entering
vehicles. In addition, off-peak hours would typically have free-flow conditions and therefore

 higher vehicular speeds. Roundabouts are a preferred intersection control for high speed
facilities because of their proven safety performance. During a Hood Canal Bridge closure,
traffic on SR 3 can back up 1 to 2 miles (see graphic below). When the bridge opens, a platoon
of traffic will send a steady stream of vehicles on SR 104 towards the Shine Road/Paradise Bay
Road intersection. With the roundabout alternative, it may be difficult for traffic on Paradise
Bay Road and Shine Road to enter westbound SR 104 due to gap availability.
One solution to remedy this concern is installing a metered-entrance single-lane roundabout.
Metered entrances are endorsed by FHWA in their Roundabout Guide (Chapter 8.1):
8.1.1 Metered entrance Roundabouts operate effectively only when there are sufficient longer and
acceptable gaps between vehicles in the circulatory lanes. If there is a heavy movement of circulating
drivers, then entering drivers at the next downstream entry may not be able to enter. This situation
occurs most commonly during the peak periods, and the performance of the roundabout can be greatly
improved with entrance metering. The concept of entrance metering at roundabouts is similar to ramp
metering on freeways. A convenient sign is a changeable one that reads “Stop on red signal” and shows
the usual yield sign for a roundabout otherwise. The sign would also include a yellow and red signal above
the sign. The operation of the sign would be to show drivers the roundabout sign, display the yellow light
and the sign “Stop on red signal,” and finally display the red light and the same text sign. This would cause
entering vehicles to stop and allow the vehicles at the downstream entrance to proceed. A queue length
detector on the downstream entrance may be used to indicate to the signal controller when the metering
should be activated and deactivated. Once on the circulatory roadway, vehicles are not stopped from
leaving the roundabout.

A similar treatment has been used at a roundabout in Kennewick, WA on the state highway
system with operational issues that are expected at Shine Road.
Detection loops can be placed on Paradise Bay Road and Shine Road. When these legs of traffic
had been delayed for more than a fixed period or exceed a length of queue, a ramp meter
signal can be activated on SR 104 to relieve some of the traffic pressure on the minor legs. This
metering signal will likely be activated only during a bridge opening and will deactivate when
the SR 104 platoon has cleared.

 SR 104/Shine
Road/Paradise Bay Road

Typical backup on SR 3 during Hood Canal Bridge closure.

Relative to a roundabout, a signal does not process vehicles as efficiently. With or without a
bridge closure, a signal would propagate longer queues which would increase the potential for
high speed, rear end crashes.
Safety Analysis
From the 2016 IAL (2009 – 2015 crash history), there were a total of 2 serious injuries and 24
non-serious crashes. 23 out of the 26 crashes were entering-at-angle crashes, and 25 out of the
26 crashes were intersection related.
First Collision Type
Entering-At-Angle
Same Direction Sideswipe
Rear-End

Fatal

Serious (indicated by Total Crashes

0

1

23

0

1

1

0

0

2

red arrows below)

 Under Federal Law, 23 United States Code Section 409, reports, surveys, schedules, lists, or data compiled or collected for the purpose of
identifying, evaluating, and planning for safety enhancements or for developing safety projects which may be implemented using Federal-aid
highway funds shall not be subject to discovery or admitted into evidence in a Federal or State court proceedings.

Since 2016, there has been 4 other crashes; 2 suspected serious injury crashes. 3 of the 4
crashes were entering-at-angle crashes.
The roundabout alternative will potentially eliminate all of the entering-at angle crashes and
significantly reduce severity of crashes relative to the signal alternative.

Community Engagement
Community engagement is expected to be conducted in the Spring of 2019. WSDOT will present
both the roundabout and signal alternatives.

Selection and Conclusion
A single-lane roundabout is recommended for this intersection based on the safety
improvements and operational benefits. A metered-entrance single lane roundabout should be
considered in the future if operational issues with a bridge opening is determined to be an

 issue. At a minimum during the initial construction, the hardware and conduit for a metered
roundabout should be installed.
Attachments:
SIDRA Analysis
Synchro Analysis

 HCM 6th Signalized Intersection Summary
3: Shine Rd/Paradise Bay Rd & SR 104

Movement
Lane Configurations
Traffic Volume (veh/h)
Future Volume (veh/h)
Initial Q (Qb), veh
Ped-Bike Adj(A_pbT)
Parking Bus, Adj
Work Zone On Approach
Adj Sat Flow, veh/h/ln
Adj Flow Rate, veh/h
Peak Hour Factor
Percent Heavy Veh, %
Cap, veh/h
Arrive On Green
Sat Flow, veh/h
Grp Volume(v), veh/h
Grp Sat Flow(s),veh/h/ln
Q Serve(g_s), s
Cycle Q Clear(g_c), s
Prop In Lane
Lane Grp Cap(c), veh/h
V/C Ratio(X)
Avail Cap(c_a), veh/h
HCM Platoon Ratio
Upstream Filter(I)
Uniform Delay (d), s/veh
Incr Delay (d2), s/veh
Initial Q Delay(d3),s/veh
%ile BackOfQ(50%),veh/ln
Unsig. Movement Delay, s/veh
LnGrp Delay(d),s/veh
LnGrp LOS
Approach Vol, veh/h
Approach Delay, s/veh
Approach LOS

10/10/2018

EBL

EBT

EBR

WBL

WBT

WBR

NBL

NBT

NBR

SBL

SBT

SBR

1
1
0
1.00
1.00

561
561
0

2
2
0
1.00
1.00

10
10
0
1.00
1.00

569
569
0

130
130
0
1.00
1.00

1
1
0
1.00
1.00

0
0
0

13
13
0
1.00
1.00

88
88
0
1.00
1.00

2
2
0

6
6
0
1.00
1.00

1800
4
0.50
0
5
0.43
11
664
1798
23.0
23.0
0.01
770
0.86
1136
1.00
1.00
17.8
4.7
0.0
9.5

1800
12
0.83
0
196
0.11
1714
12
1714
0.4
0.4
1.00
196
0.06
196
1.00
1.00
27.2
0.1
0.0
0.2

1800
213
0.61
0
819
0.54
1525
213
1525
5.2
5.2
1.00
819
0.26
964
1.00
1.00
8.6
0.2
0.0
1.5

1786
4
0.25
1
81
0.26
85
32
1523
0.0
1.1
0.12
457
0.07
457
1.00
1.00
19.2
0.3
0.0
0.4

1786
28
0.46
1
348
0.26
1333
0
0
0.0
0.0
0.87
0
0.00
0
1.00
0.00
0.0
0.0
0.0
0.0

1786
104
0.85
1
416
0.26
1216
120
1433
3.4
4.5
0.87
472
0.25
472
1.00
1.00
20.4
1.3
0.0
1.6

0.0
A
668
22.9
C

22.6
C

27.3
C

8.7
A

19.5
B

0.0
A
32
19.5
B

0.0
A

21.6
C

2
22.5
4.5
18.0
3.1
0.1

3
12.4
4.5
5.0
2.4
0.0

4
34.0
4.5
43.5
25.0
4.4

6
22.5
4.5
18.0
6.5
0.4

7
4.9
4.5
5.0
2.2
0.0

8
41.5
4.5
43.5
31.3
5.7

1646
4
0.25
11
8
0.01
1567
4
1567
0.2
0.2
1.00
8
0.48
114
1.00
1.00
34.1
36.6
0.0
0.1
70.8
E

Timer - Assigned Phs
Phs Duration (G+Y+Rc), s
Change Period (Y+Rc), s
Max Green Setting (Gmax), s
Max Q Clear Time (g_c+I1), s
Green Ext Time (p_c), s
Intersection Summary
HCM 6th Ctrl Delay
HCM 6th LOS

Shine Rd 10/10/2018 2018 PM Existing
jmn

1.00
No
1800
660
0.85
0
766
0.43
1787
0
0
0.0
0.0
0
0.00
0
1.00
0.00
0.0
0.0
0.0
0.0

1.00
No
1800
862
0.66
0
967
0.54
1800
862
1800
29.3
29.3
967
0.89
1137
1.00
1.00
14.2
8.1
0.0
12.1
22.3
C
1087
19.7
B

1.00
No
1786
0
0.92
1
27
0.00
105
0
0
0.0
0.0
0
0.00
0
1.00
0.00
0.0
0.0
0.0
0.0

1.00
No
1786
4
0.50
1
19
0.26
74
0
0
0.0
0.0
0
0.00
0
1.00
0.00
0.0
0.0
0.0
0.0
0.0
A
120
21.6
C

1786
12
0.50
1
37
0.26
143
0
0
0.0
0.0
0.10
0
0.00
0
1.00
0.00
0.0
0.0
0.0
0.0
0.0
A

20.9
C

Synchro 10 Report
Page 1

 Queuing and Blocking Report
2018 PM Existing

10/10/2018

Intersection: 3: Shine Rd/Paradise Bay Rd & SR 104
Movement
Directions Served
Maximum Queue (ft)
Average Queue (ft)
95th Queue (ft)
Link Distance (ft)
Upstream Blk Time (%)
Queuing Penalty (veh)
Storage Bay Dist (ft)
Storage Blk Time (%)
Queuing Penalty (veh)

EB
TR
227
140
213
762

WB
L
40
15
42

200

WB
T
153
114
162
920

WB
R
53
28
60

NB
LTR
36
11
36
925

SB
LTR
92
35
84
803

200

1
0

Network Summary
Network wide Queuing Penalty: 0

Shine Rd
jmn

SimTraffic Report
Page 1

 SITE LAYOUT
Site: 101 [SR 104/Paradise/Shine 1-lane 2018 PM]
SR 104/Paradise/Shine 1-lane
Roundabout

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 MOVEMENT SUMMARY
Site: 101 [SR 104/Paradise/Shine 1-lane 2018 PM]
SR 104/Paradise/Shine 1-lane
Roundabout

Movement Performance - Vehicles
Mov
ID

OD
Mov

Demand Flows
Total
HV
veh/h
%

Deg.
Satn
v/c

Average
Delay
sec

Level of
Service

95% Back of Queue
Vehicles
Distance
veh
ft

Prop.
Queued

Effective Average
Stop Rate Speed
per veh
mph

South: Shine Rd
3

L2

1

0.0

0.014

9.5

LOS A

0.1

1.4

0.22

0.51

8

T1

1

0.0

0.014

5.0

LOS A

0.1

1.4

0.22

0.51

36.3

18

R2

14

0.0

0.014

4.8

LOS A

0.1

1.4

0.22

0.51

35.4

16

0.0

0.014

5.1

LOS A

0.1

1.4

0.22

0.51

35.5

L2

11

0.0

0.712

10.4

LOS B

7.1

183.4

0.54

0.53

35.1

6

T1

618

5.0

0.712

6.1

LOS A

7.1

183.4

0.54

0.53

35.1

16

R2

141

1.0

0.712

5.7

LOS A

7.1

183.4

0.54

0.53

34.4

771

4.2

0.712

6.1

LOS A

7.1

183.4

0.54

0.53

35.0

Approach

36.2

East: SR 104
1

Approach

North: Paradise Bay Rd
7

L2

1

3.0

0.005

12.6

LOS B

0.0

0.7

0.64

0.61

33.9

4

T1

1

3.0

0.005

8.1

LOS A

0.0

0.7

0.64

0.61

34.1

14

R2

Approach

1

3.0

0.005

7.9

LOS A

0.0

0.7

0.64

0.61

33.3

3

3.0

0.005

9.6

LOS A

0.0

0.7

0.64

0.61

33.8
34.3

West: SR 104
5

L2

96

2.0

0.087

9.1

LOS A

0.4

10.5

0.08

0.63

2

T1

2

0.0

0.087

4.7

LOS A

0.4

10.5

0.08

0.63

34.5

12

R2

7

0.0

0.087

4.4

LOS A

0.4

10.5

0.08

0.63

33.7

Approach

104

1.8

0.087

8.8

LOS A

0.4

10.5

0.08

0.63

34.3

All Vehicles

895

3.8

0.712

6.4

LOS A

7.1

183.4

0.48

0.55

34.9

Site Level of Service (LOS) Method: Delay & v/c (HCM 6). Site LOS Method is specified in the Parameter Settings dialog (Site tab).
Roundabout LOS Method: Same as Signalised Intersections.
Vehicle movement LOS values are based on average delay and v/c ratio (degree of saturation) per movement.
LOS F will result if v/c > 1 irrespective of movement delay value (does not apply for approaches and intersection).
Intersection and Approach LOS values are based on average delay for all movements (v/c not used as specified in HCM 6).
Roundabout Capacity Model: SIDRA Standard.
SIDRA Standard Delay Model is used. Control Delay includes Geometric Delay.
Gap-Acceptance Capacity: SIDRA Standard (Akçelik M3D).
HV (%) values are calculated for All Movement Classes of All Heavy Vehicle Model Designation.

SIDRA INTERSECTION 7.0   Copyright © 2000-2017 Akcelik and Associates Pty Ltd   sidrasolutions.com
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