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LOCAL ROAD SAFETY PLAN

Project Decision Tree Example

View the full Palm Beach County Local Road Safety Plan
 

 

Project Decision Tree Example 

PALM BEACH COUNTY LOCAL ROAD SAFETY 

PLAN DEVELOPMENT 

Urban/Suburban Intersection 

Intersection of Lake Worth Rd (FL 802) & S. Jog Road 

Rank 12, Intersection ID 1712 
 

Site Overview 

Project Decision Tree Example 

Source: Google map, 2018 imagery Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 

Lake Worth Road

Jog Road
 

 

 

Site Overview 

• Four leg signalized urban intersection

• Total entering vehicles = 86,000 vehicles per day (VPD) (2016)

• Speed limit on all approaches is 45 mph

• All approaches are media divided beyond intersection extents

• Exclusive double left turns on all approaches

• Exclusive right turn on eastbound (EB) approach (heading south)

• Pedestrian crosswalks at all approaches

• Both roads have existing bicycle lanes in both directions

• Northbound (NB), southbound (SB), and westbound (WB) are 5-lane approaches;

EB is a 6-lane approach

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 
 

 

 

 

 

 

-

Urban/Suburban 

Signalized 

Intersection Project 

Development 

Process 

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 

* Conduct Analysis/Evaluation, e.g., reference 

CAP-X, NHI Alternative Intersections and 

Interchanges Course (FHWA-NHI-380109) to 

Identify Appropriate Design. (Median U-Turn, 

Displaced Left, Roundabout, Bowtie, 

Quadrant, Jug Handle, Echelon, etc.) 

** Refer to Strategy Considerations/Prompt 

Sheets for Guidance on Selecting Strategies 
 

 

 

 

Step 1 – Site Demographics 

Source: Google map, 2018 imagery 

Speed Limit Cross Product > 1400? Yes

SLCP = 45 MPH x 45 MPH = 2,025 

ADT > 30,000 VPD? Yes

Entering Vehicles=86,000 VPD 

Approach Lanes>6? Yes

Eastbound is a 6-lane approach 

Available R/W? No

Intersection is surrounded by several 

businesses and property acquisition is a 

costly alternative Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 

Lake Worth Rd

45 mph

Jog Rd

45 mph
 

 

 

 

 

 

 Signal heads appear to be outdated

(chipped paint) and are inconsistent

(based on visual inspection)

 Some signal heads have LED lenses

while some do not

 EB and WB signal heads have

background shields, while NB and

SB approaches do not

 Current signal heads are 12”

Step 2 – Signal Hardware Assessment 

Signal heads mounted on the 

SW corner mast arm Project Decision Tree Example 

Source: Google Street View Urban/Suburban Intersection Image capture: May 2017 Lake Worth Rd (FL 802) & S. Jog Road 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Step 2 – Signal Hardware Improvements 

 Improve Signal Visibility:

 Install signal background shields on northbound and southbound

heads to improve visibility.

 Install supplemental mast arm-mounted signal heads so that each

lane has a dedicated signal head. This included mast arms on the

approach side and far side of the intersection. Source: Google Street View, Image capture: June 2017 

 Note: this upgrade requires a structural analysis of each mast

arm/span wire where a signal will potentially be added.

 Place lane dedication regulatory sign at the beginning and the end of R3-H8ec R3-H8eb 

channelizing line per USDOT MUTCD Requirements:

 Place R3-H8ec on northbound, southbound, and westbound (one

each)

 Place R3-H8eb on eastbound

 Retroreflectivity of the existing signs and markings appears to be in good

shape. Upgrading existing signs for retroreflectivity is not recommended.

 There are existing raised markings for all longitudinal markings and a Source: Google Street View, Image capture: June 2017 

project to implement is not required.

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 
 

 

 

 

 

 

 

 

 

 

 

 

 

Step 3 – Driver Awareness, 

Compliance Strategies 

 The intersection experienced 1 fatal crash and 2 serious injury crashes

from 2011 through 2015. Of these crashes, the single fatal crash and

one of the serious injury crashes were right-angle crashes.

 Neither of the angle crashes were noted as visibility-related;

however, visibility will be addressed with upgraded signals as 

previously noted.

 The fatal crash involved a pedestrian and will be best addressed

with pedestrian-specific countermeasures.

 The volume of angle crashes is low – advanced dilemma warning

systems may address the crashes but the cost is significant. An 

advanced dilemma system is not recommended at this time.

 There were 6 red-light running crashes from 2011 through 2015, of

which 3 were minor injury, 1 was possible injury, and 2 were property

damage only.

 Red-light running compliance lights combined with enforcement

may reduce these crashes; however, these are not the target

crashes. Confirmation lights are not recommended.

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 
 

 

 

 

 

 

 

 

 

 

 

 

Step 4 – Signal Phasing and Turn 

Facilities Strategies 

 11 crashes involved left turns of which 3 were severe. Specific

details on gap acceptance were not available, though they

are presumed unrelated given the protected left turn signal

timing (assumed based on number of lanes).

 Storage length of turn facilities is enough to

accommodate peak turning movements without through

blocking.

 Turn radius analysis was completed using AutoTurn (design

vehicle: WB-62). (Details next figure)

 It appears concurrent eastbound to northbound and

westbound to southbound left turn movements have

almost no clearance, which may be slowing down

turning traffic. This may be leading to the high level of

“Following Too Closely” Crashes (29 crashes).

Source: Google Street View, Image capture: July 2017 

Project Decision Tree Example 

Urban/Suburban Intersection 

Intersection of Lake Worth Rd (FL 802) & S. Jog Road 
 

 

 

 

 

 

 

 

 

Step 4 – Signal Phasing and Turn 

Facilities Strategies 

 Left turn movements on opposite approaches are

related to design vehicle WB-62 drafted with

AutoTurn. Green path represents total turning width

of design vehicle.

 Signal Phasing improvements

 Update signal phasing to avoid concurrent

protected left turns of opposite approaches,

especially on eastbound and westbound

approaches.

 Since there is an urgent care facility 200’ east of

intersection, and a fire station 0.6 miles west of

intersection, and a fire station almost a mile

north of intersection, preemption should be

utilized.

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road Source: Google map, 2018 imagery 
 

 

Step 4 – Signal Timing/ Geometric 

Improvements 

 It is unknown when the last signal timing/capacity

analysis was completed. Therefore, it is 

recommended to study the signal to improve 

Capacity/LOS by updating timing/phasing of 

intersection to improve operation.

 Intersection geometry improvements

 Shift back stop-bars and crossing lines to 

make more space for design vehicle 

movements (see AutoTurn Analysis).

 Restripe pavement markings.

 Due to cost and existing heavy left turn

volumes on all approaches, alternative 

intersection types are not recommended.

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 
 

 

-

Step 5 – Access Management 

Access Management 

Strategies 

Undivided 

and/or Access 

Related 

Crashes? 

Yes 

No 

All of the approaches are divided and all of the 

access points are right-in/right-out. Therefore, access 

management improvements are not recommended. 

Source: Google Map, Image capture: July 2017 

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 
 

 

 

 

 

 

 

Step 6 – Pedestrian Considerations 

 The one fatal crash at the site involved a pedestrian.

Additionally there is:

 Evidence of high volume pedestrian traffic

 Presence of handicapped sidewalk/crosswalk users

 Two bus stops within 500’ on all four legs (totally eight

bus stops)

 Existence of surrounding businesses that generate high

volume of pedestrian traffic

 Crosswalks with long crossing distances (150’-170’)

 Recommended pedestrian upgrades include





Pedestrian countdown timers with pedestrian leading 

interval signal timing

Future consideration for raised pedestrian refugee 

islands (likely width would have to be taken from lanes

and added to median)

Source: Google Street View, Image capture: July 2017 

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 
 

 

 

Step 7 – Bicyclist Considerations 

Source: Google Street View, Image capture: July 2017 

 Bike lanes already exist along all approaches in all

directions.

 5 injury crashes involving bicycles occurred from

2011-2015.

 Proposed bicycle features include leading bicycle

interval signal timing, and marking the full bike lane 

with green markings and white bicycle markings.

 Advanced bicyclist facilities, like bike bokes and bicycle

detectors, should be considered only after lower cost

countermeasures do not improve bicyclist safety.

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road 
 

 

Planning Level Cost Estimate 

Below is the break-down of cost estimates of the recommendation: 

Strategy Unit Cost Quantity Sub-total 

Retroreflective Signal Backplates Signal Head $ 110.00 23 $ 2,530 

Supplemental Signal Heads Intersection $ 2,700.00 1 $ 2,700 

Structural Analysis for Additional Signal 

Heads 

Mast Arm/ 

Span Wire $ 2,400.00 8 $ 19,200 

Upgrade Signs and Markings Approach $ 3,000.00 4 $ 12,000 

Signal Phasing and Timing Improvements Intersection $ 5,000.00 1 $ 5,000 

Install Pedestrian Countdown Timers with leading 

pedestrian interval Intersection $ 14,300.00 1 $ 14,300 

Total approximate project cost $ 55,730 

Project Decision Tree Example 

Urban/Suburban Intersection 

Lake Worth Rd (FL 802) & S. Jog Road