Project Study Report€¦ · I NT RO DUCT I O N 2 2 . BACKG RO UND 6 3 . P URP O S E AND NE E D 7 4...

Project Study Report

APPROVAL RECOMMENDED: _______________________ ________________________ PROJECT MANAGER PROJECT MANAGER

Vivian Sy Barbara Kimberly Duran

APPROVED: _______________________ ________________________ ______ CIVIL ENGINEERING CIVIL ENGINEERING DEPARTMENT DATE DEPARTMENT CHAIR ASSISTANT PROFESSOR Xudong Jia Yongping Zhang

San Bernardino County - Cajon Junction

Table of Contents 1. INTRODUCTION 2

2. BACKGROUND 6

3. PURPOSE AND NEED 7

4. DEFICIENCIES 8

5. ALTERNATIVES 9 SR-138 Realignment 10 Wagon Train Road Realignment 10 Single Point Interchange 10 Diverging Diamond Interchange 12 Hybrid Interchange 13

6. COMMUNITY INVOLVEMENT 15

7. ENVIRONMENTAL DETERMINATION/DOCUMENTATION 16

8. BENEFIT AND COST ANALYSIS 17

9. RECOMMENDED ALTERNATIVE 19

10. PROJECT PERSONNEL 21

11. ATTACHMENTS 25 Attachment A - Preliminary Environmental Analysis Report (PEAR) Attachment B - Intersection Control Evaluation (ICE) Attachment C - Geometric Approval Drawing (GAD) Attachment D - Advanced Planning Study (APS) Attachment E - Construction Staging Plan

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1. INTRODUCTION State Route 138 (SR-138) is a state highway in California. SR-138 runs East to West beginning at SR-14 in Palmdale and ending at SR-18 in Crestline. Due to growth and expansion of communities in Phelan and the surrounding San Bernardino county, Caltrans has determined that the existing design will not provide adequate service to the community in the years to come. The purpose of this project is to conduct a feasibility study to provide interchange improvements at State Route 138 and Interstate 15. Caltrans has given a team of 15 students from California State Polytechnic University, Pomona the task of redesigning the interchange of SR-138, from post mile 14.5 to 16 in the city of Phelan, to improve capacity and operations at this interchange. The project, also known as the Cajon Junction Improvement Project, will allow for future region growth for years to come. This project study report summarizes the results of the year-long traffic and environmental analysis, as well as the geometric designs that were evaluated in order to determine the recommended alternative design for the SR-138 and I-15 interchange. A detailed summary of the traffic and environmental analysis can be found in the Intersection Control Evaluation (ICE) and Preliminary Environmental Analysis Report (PEAR), which accompanies this report.

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Figure 1. Project Location Relative to Los Angeles

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Figure 2. Project Study and Design Boundary

The highway under construction is located along State Route 138, in the city of Phelan in the San Bernardino County (Figure 1). The project location was divided into a study boundary and a design boundary. The project study boundary is denoted in blue on Figure 2, and the project design boundary is denoted in red. Within the project study boundary, a traffic analysis was performed of the existing State Route 138 mainline, as well as the intersections around the mainline. A preliminary environmental analysis was also performed to determine the level of impact that the project would have on the surrounding area. Within the project design boundary, several alternatives were designed.

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Figure 3. County of San Bernardino General Plan Land Use Map The Land Use Map (Figure 3) was developed using the City of San Bernardino's General Plan. The area within the project study boundary is designated for a diverse land use ranging from very low density residential and open space in the north-east, commercial use in the south-east, commercial and very low-density residential use in the north-west, and open green space in the south-west with proposed residential area further south.

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2. BACKGROUND The project is located in the unincorporated area of San Bernardino County, California. The project involves the improvement of the Cajon Junction interchange from postmile 14.5 to 16. SR-138 runs East to West beginning at SR-14 in Palmdale and ending at SR-18 in Crestline. Our section of SR-138 currently has four mixed flow lanes with several grade separations and is classified as a minor arterial highway by the California Road System. This segment of SR-138 serves as the primary route connecting the cities of Phelan and Wrightwood to Interstate 15. The primary purpose of this project is to improve or replace the existing interchange to accommodate expected future traffic. SR-138 may need to be realigned in order to meet vertical clearance over I-15. There are two local roads that currently intersect SR-138, Cajon Boulevard and Wagon Train Road that have to be taken into consideration during the design process. The final project deliverable will closely resemble a feasibility study of the above improvements. Local road layout recommendations will be given to the County of San Bernardino based on the Traffic Impact Analysis. Detailed design of local roads is not included in the project scope because they are out of Caltrans jurisdiction. The study and design boundary were determined based on the area needed for preliminary environmental and traffic analyses in addition to the area necessary for the proposed geometric improvements.

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3. PURPOSE AND NEED

Purpose: The project purpose is to relieve congestion, improve ramp and intersection operations along State Route 138 and Interstate 15 interchange (Cajon Junction).

Need: 1. Improve capacity to accommodate increasing traffic from both State Route 138

East and State Route 138 West. 2. Improve operations between the intersections in the vicinity of the interchange. 3. Mitigate potential impacts to Interstate 15.

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4. DEFICIENCIES

Synchro 10 was used for all traffic analyses for different intersection controls. Given the design volumes, the team determined two to three lanes in each direction was necessary. Synchro 10 was unable to report an intersection level of service for roundabouts with more than 2 approach lanes. This is due to HCM 2016 not detailing the analysis of 3 lane roundabout. Due to our need of three lanes and the rarity of a 3 lane roundabout in the state of California, we reported all roundabout levels of service as not applicable nd do not recommend this control type for any intersections in this project.

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5. ALTERNATIVES

Interchange Types

Single Point Interchange

Diverging Diamond Interchange

Hybrid Interchange

Table 1: Viable Alternatives

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SR-138 Realignment The existing conditions of the SR-138 restricted the expansion of the bridge due to clearance issues with the I-15. The realization of these issues led our team to provide another option that would allow the projects needs to be met. Therefore, the SR-138 was realigned creating an approximate angle of 75 degrees between the existing I-15 and the new realigned SR-138. The modified design has been implemented in the following alternatives.

Wagon Train Road Realignment Due to the realignment of SR-138, Wagon Train Road had to be realigned. The benefit of the realignment is the distance amongst intersections increases. This allows left turns from Wagon Train Rd onto SR-138 west to have

Single Point Interchange The Single Point Interchange includes four on-ramps and four off-ramps. The single point two on-ramps and two off-ramps intersect at a single signalized intersection at the center of the interchange. The remaining two on-ramps and off-ramps are channelized to allowing free flow access. The ramps terminating at the intersection have an approximate angle of twenty-seven degrees. The channelized ramps have an approximate angle of twenty degrees. Typical interchanges require two intersections for ramp control at both ends of the interchange. The single point interchange eliminates the need for two, combining the ramps into one larger intersection. The loss of the additional intersection theoretically reduces vehicle delay. However, this interchange is not favorable to pedestrians due to the complex layout of ramps. The following dimensions were chosen to meet the requirements given by the Caltrans Highway Design Manual (HDM): 12-15 foot lane width, 4 foot left ramp shoulder, 8 foot right ramp shoulder and the mainline shoulder widths range from 3 to 8 feet. Along with

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the HDM, the Manual on Uniform Traffic Control Devices (MUTCD) was also referenced to achieve lane drops. The HDM was used to meet all other requirements, including cross-section design. The traffic analysis was performed using Synchro 10 and the traffic volumes were found using SCAG 2040 and the Highway Capacity Manual (HCM 2016) to approximate the level of service. The analysis was performed for both the AM and PM peak hour volume; results can be found in the ICE report (Attachment B). The Single Point Interchange (SPI) is a viable alternative to the proposed project and incorporate smart traffic flow system. The SR-138 will have its main alignment shifted north which cuts into the mountain found in the northeast corner of the Cajon Junction near the current I-15 North on ramp. Access will be lost to Santa Fe Road, so the the design team will have to agree on a solution to present to utility companies to move or provide access to the existing electric poles. Since the existing bridge will not be large enough to accommodate the SPI alternative, a new bridge will need to be constructed which will cause delays for users during the construction phase of the project and loss of business for the area. The design team will need to plan on how they will continue to provide access to businesses and where construction equipment will be stored when not in use. Since the SPI is an unfamiliar traffic intersection for users in this area, the design team should address how they will help residents adjust to the new traffic configuration and prevent initial traffic collisions after the project is completed. An Advance Planning Study (APS) aids in the development of a cost estimate and illustrates any requirements or constraints for the structures involved in the project. Each structure will have an APS that consists of a plan sheet that contains the typical cross sections, elevations, and basic dimensions, along with a cost estimate for the structure. The Single Point Interchange requires a new double span of 164 ft and 161 ft with a vertical clearance height of 18.7 ft. that accompanies the realignment of Route 138. Each span is made from precast concrete (See Section 8, Cost Estimate). The APS for the Single Point Interchange can be found in Attachment D.

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Diverging Diamond Interchange The diverging diamond interchange design will include four on-ramps and four off-ramps; with signal control at each off-ramp. The ramps are connected to the SR-138 with an approximate twenty-five degree angle; this angle was used to implement a continuous movement. The diverging diamond interchange is also referred to as a “double crossover diamond”, as traffic is traveling in two directions on opposite sides of the road and cross in an “x” type manner. The interchange

reduces the amount of conflict points and improves the site distance. The median will be included to separate traffic traveling in two different directions to decrease the amount of head on collisions (Attachment B). The following dimensions were chosen to meet the requirements given by the Caltrans Highway Design Manual (HDM): 14 foot lane width, 4 foot left ramp shoulder, 8 foot right ramp shoulder and the mainline shoulder widths range from 3 to 6 feet. Along with the HDM, the Manual on Uniform Traffic Control Devices (MUTCD) was also referenced to achieve lane drops. The HDM was used to meet all other requirements, including cross-section design. The traffic analysis was performed using Synchro 10 and the traffic volumes were found using SCAG 2040 and the Highway Capacity Manual (HCM 2016) to approximate the level of service. The analysis was performed for both the AM and PM peak hour volume; results can be found in the ICE report (Attachment B). Due to the high volumes, the design engineers added a lane (3 lanes in total) to accommodate for this change and to meet the desired level of service. The Diverging Diamond Interchange (DDI) is considered as an alternative to reduce the number of runaway truck incidents and provide better access to all directions of travel from SR-138 to I-15. As in many of the viable alternatives, the SR-138 has its main alignment shifted north which cuts into the mountain found in the northeast corner of the Cajon Junction near the current I-15 North on ramp. Electric pole utilities will have to be relocated if access is lost to Santa Fe Road which is located near the I-15 North on ramp. The new I-15 South off ramp will also encroach on the property of private owners and businesses; therefore, the right of way may need to be purchased at the discretion of decisions drafted by the geometric design team. In the realignment of the SR-138, the bridge crossing the Cajon wash may need to be improved. Although, this area falls in the boundary of where a possible endangered species habitat may exist and final design considerations will need to be made after the results of a more in-depth

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environmental analysis report. As the DDI involves switching the side that traffic travels from the typical right side to the left side of the road, it should be addressed by the design team how to help residents of the area adjust to the new traffic configuration. Since the existing bridge will not be large enough to accommodate the DDI alternative, a new bridge will need to be constructed which will cause changes in the existing floodplain and infiltration for the area. The design team will need consider the material that will be used for paving the roadway and a new drainage system across the bridge to ensure the drainage conditions for the area remain the same or decrease from what existed before the improvement.

An Advance Planning Study (APS) aids in the development of a cost estimate and illustrates any requirements or constraints for the structures involved in the project. Each structure will have an APS that consists of a plan sheet that contains the typical cross sections, elevations, and basic dimensions, along with a cost estimate for the structure. The Diverging Diamond Interchange requires a new double 330ft. span with a vertical clearance height of 18.9ft. that accompanies the realignment of Route 138. Each span is made from precast concrete (See Section 8, Cost Estimate). The APS for the Diverging Diamond Interchange can be found in Attachment D.

Hybrid Interchange The hybrid interchange is a combination of a partial cloverleaf and diamond interchange. This interchange consists of a quarter segment of a clover diamond and spread diamond configuration. The configuration has two on-ramps and two off-ramps. The purpose of this layout design was to mitigate collisions, improve traffic flow, and reduce congestion along State Route

138 and Interstate 15. The partial cloverleaf design helps to slow down oncoming vehicles approaching State Route 138 from the off-ramp from Interstate 15 South thus reducing collision.

The Hybrid alternative was proposed as a viable alternative to primarily reduce the number of runaway truck incidents. As in many of the viable alternatives, the SR-138 has its main alignment shifted north which cuts into the mountain found in the northeast corner of the Cajon Junction near the current I-15 North on ramp. The realignment of SR-138 will also need to address access to Santa Fe Road, a utility road for electricity poles. The new I-15 South off ramp will also encroach on the property of private owners and businesses; therefore, the right of

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way may need to be purchased at the discretion of decisions drafted by the geometric design team. For the on ramp of I-15 South, the new alignment falls into the area where a possible endangered species habitat may exist and final design considerations will need to be made after the results of a more in-depth environmental analysis report. Accompanying the realignment of SR-138, new intersections for Cajon Boulevard and Wagon Train Road will need to be designed as well so that they can meet orthogonally along the state highway.

The Hybrid interchange is considered as an alternative to provide better access to all directions of travel from SR-138 to I-15. Once again, the realignment of SR-138 is shifted north which cuts into the mountain found in the northeast corner of the Cajon Junction near the current I-15 North on ramp. Electric pole utilities will have to be relocated if access is lost to Santa Fe Road which is located near the I-15 North on ramp. The new I-15 South off ramp will also encroach on the property of private owners and businesses; therefore, the right of way may need to be purchased at the discretion of decisions drafted by the geometric design team. In the realignment of the SR-138, the new I-15 southbound onramp will require right of way from the Cajon wash. Although, this area falls in the boundary of where a possible endangered species habitat may exist and final design considerations will need to be made after the results of a more in-depth environmental analysis report. The design team will need consider the material that will be used for paving the new ramps and the bridges that make them up to ensure the drainage conditions for the area remain the same or decrease from what existed before the improvement. If the materials being used in the construction of the bridge are renewable materials, the design team can also reduce the impact to local climate because of the carbon footprint of the structures. An Advance Planning Study (APS) aids in the development of a cost estimate and illustrates any requirements or constraints for the structures involved in the project. Each structure will have an APS that consists of a plan sheet that contains the typical cross sections, elevations, and basic dimensions, along with a cost estimate for the structure. The Hybrid Interchange requires a new double 152.5 ft. span with a vertical clearance height of 18.3 ft. that accompanies the realignment of Route 138. Each span is made from precast concrete (see cost estimate). The Hybrid Interchange also requires 2 additional bridges on the southwest of the interchange. The I-15 southbound off-ramp and on-ramp both required since they go over the Cajon wash. The APS for the Hybrid Interchange can be found in Attachment D.

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6. COMMUNITY INVOLVEMENT Once construction begins on the new intersection configuration, users will see a delay in their trip. Caltrans must take steps to ensure that travel is not completely stopped or heavily delayed because the Cajon Junction is the only route to connect users from San Bernardino to the high desert. During construction planning, the project will have to be divided into multiple stages to prevent having to shut down the Cajon Junction completely. A community impact assessment (CIA) should be conducted to determine how the area will be impacted if it is built. Other complications such as access for off-highway vehicles (OHV) and access to utility roads may be present on the northeast side of the Cajon Junction near the northbound onramp for the I-15. A representative from Caltrans should be present at town hall meeting for the city of Phelan to point out the benefits of the Cajon Junction Improvement Project and address concerns that may be brought up.

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7. ENVIRONMENTAL DETERMINATION/DOCUMENTATION After the project design boundary and project study boundary were established, a preliminary environmental report (PEAR) was written to evaluate how environmental concerns will affect the project’s scope, schedule, and costs for environmental compliance. The most pressing concerns found in the report include biological resources, water quality and stormwater runoff, and wildfire concern. Data for each section of the PEAR were acquired from federal, state, and local databases. The overlay for biological resources was acquired from the county of San Bernardino land use services database. The Arroyo Toad, an endangered species as classified by US Fish and Wildlife Services, was shown to be possibly present in the Cajon Junction area. In the Special environmental considerations section of the PEAR, it is recommended that a biological assessment be done for the area to determine if section 7 consultation will be required for the proposed project. From the California Drinking Water board, the contaminants in the groundwater were found for the Cajon Junction to see what levels need to be maintained during construction. Low levels of Nitrate are found in the groundwater, but are below maximum contamination levels (MCL). The Cajon Junction is located in an area of moderate to very high hazard of wildfires. To reduce the likelihood of wildfires jumping across the roadways, it was recommended to create a maintenance team to periodically remove material that can act as a fuel source for fires. The addition of gravel channels on the outside of the

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shoulders for the roadway were recommended to prevent a fire from spreading by increasing the distance it would need to jump.

8. BENEFIT AND COST ANALYSIS Cost Analysis The costs for the three interchange alternatives were calculated based on fifteen categories that are typically included in any Caltrans Planning Level Type Study. The categories are as follows: earthwork, pavement structural section, structure items, right-of-way, drainage, speciality items, environmental, traffic items, detours, minor items, mobilization, supplemental, state furnished materials, and time related overhead. In addition, the contingency was calculated as 25% of the overall total project cost to include unpredicted items and any quantified risk . The Caltrans Basic Engineering Estimation System was used to determine standard unit prices for materials and labor, based on the size and estimated completion date of the project. A detailed summary of the costs associated with each interchange alternative can be viewed in Table 2 below.

The Single Point Interchange had the lowest total cost at $191 million, followed by the Diverging Diamond Interchange at $257 million, and the Hybrid Interchange at $314 million.

ITEM SPI DDI HYBRID

Earthwork $65,000,000 $116,000,000 $98,000,000

Pavement Structural Section $6,000,000 $4,000,000 $6,000,000

Structure Items $21,000,000 $11,000,000 $47,000,000

Right of Way $21,000,000 $15,000,000 $27,000,000

Drainage $6,000,000 $7,000,000 $9,000,000

Speciality Items $2,000,000 $3,000,000 $4,000,000

Environmental $6,000,000 $7,000,000 $9,000,000

Traffic Items $6,000,000 $7,000,000 $9,000,000

Detours $6,000,000 $7,000,000 $9,000,000

Minor Items $2,000,000 $3,000,000 $4,000,000

Mobilization $6,000,000 $9,000,000 $11,000,000

Supplemental $2,000,000 $4,000,000 $4,000,000

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State Furnished Materials $6,000,000 $9,000,000 $11,000,000

Time Related Overhead $6,000,000 $9,000,000 $11,000,000

Contingencies - PSR $30,000,000 $46,000,000 $55,000,000

Total $191 M $257 M $314 M

Table 2: The total cost outcome for each alternatives are shown above.

Benefit Analysis The benefits of implementing each new design alternative were determined by comparing the No Build alternative to each of the new design alternatives. The total delay, emissions, fuel and operation cost from the no build were all compared to the new design alternatives. The comparison was made to determine the decrease in all of the categories listed above, this shows the benefits that the new designs will have on this location. Each of the categories taken into account were found using Synchro 10. Each alternative provided us with a different delay, emission and fuel discharge values, the units vary. The difference between the new alternatives and the No Build design was then found and calculated using the unit prices. The future unit prices were determined from the Caltrans Vehicle Operation Cost Parameters. The benefits for each alternative can be found below (Table 3).

CATEGORY SPI DDI HYBRID

Total Delay Reduction $474,682,280 $318,950,412 $557,747,105

Fuel and Operation Cost Reduction $23,231,426 $28,622,576 $34,143,946

Emissions Reduction $287,031 $310,156 $498,541

Total $498,200,737 $347,883,144 $592,389,592

Table 3: The total benefit outcome for each of the alternatives are shown above.

CATEGORY SPI DDI HYBRID

Total Delay Reduction $474,682,280 $318,950,412 $557,747,105

Fuel and Operation Cost Reduction $23,231,426 $28,622,576 $34,143,946

Emissions Reduction $287,031 $310,156 $498,541

Total $498,200,737 $347,883,144 $592,389,592

Table 4: The total benefit outcome for each of the alternatives are shown above.

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Benefit/Cost Analysis

CATEGORY SINGLE POINT INTERCHANGE

DIVERGING DIAMOND INTERCHANGE HYBRID

Cost $ 191 M $257 M $314 M

Benefit $ 498 M $348 M $592 M

Total 2.6 1.4 1.9

Table 5: The final benefit cost ratio was calculated and compared to help determine the best possible option for our project.

9. RECOMMENDED ALTERNATIVE In order to compare the Interchange alternatives and select the design that best satisfies the purpose and needs of the project, the Caltrans’ Weighted Decision Matrix was used to evaluate the alternatives. The Weighted Decision Matrix allowed for the comparison of the alternatives against specific categories with varying degrees of weights. The three alternatives were evaluated and compared against eight categories: traffic operations, benefit/cost ratio, user expectation, constructability, environmental impacts, r/w impacts, maintainability, and adaptability. Each of the categories have varying degrees of weights.Traffic operations was weighed the most as all three of the project’s needs were focused around relieving congestion, improve ramp and intersection operations. Thus, this category received the full weight of 5. The construction costs and benefits that would generate over a 20-year period for each alternative were calculated and taken into consideration as the second highest category, with the weight of 4.5. User expectations was rated the third highest because the drivers and traffic need to be able to adapt easily through the alternative.Therefore, it was assigned a weight of 3.5. Constructability, environmental Impacts, and right of way impacts are tied as fourth highest because due to the location of the interchange all three of these categories are evenely important in deciding on the recommended alternative.Other minor factors such as maintainability and adaptability were considered and assigned the weights of 2 and 1, respectively. After assigning weights to each of the categories, each alternative was given a score from 1 to 5 based on how well the alternative performed in a given category. Finally, each of the scores were multiplied by the weight of their respective categories and in the end, each score was totaled, as shown in Table 6.

CATEGORY WEIGHT SPI SCORE

DDI SCORE

Hybrid SCORE

Traffic Operation 5 20 15 25 Benefit/Cost 4 20 16 16

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Ratio User

Expectations 3.5 10.5 7 14

Constructability 3 9 6 12 Environmental

Impacts 3 9 9 6

Right of Way Impacts

3 12 12 6

Maintainability 2 6 6 4 Adaptability 1 3 2 4

Total 89.5 73 87 Table 6: Weighted Decision Matrix, used to determine the final recommended alternative. The Single Point Interchange had the highest final score of 89.5 compared to the Diverging Diamond Interchange score of 73 and the Hybrid Interchange score of 87. This alternative best satisfies the purpose and needs of the project and provides the best traffic operations, while providing the most benefits to the community, and lowest cost to to build. From there, a geometric approval drawing, or GAD for short, was drafted (see Attachment C)..

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10. PROJECT PERSONNEL

Project Managers

Vivian Sy Barbara ‘Kimberly’ Duran

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Traffic Team

Alejandro Tapia, EIT

Jerome Marquez, EIT Jasmin Hurtado, EIT

Ricardo Torres Nahum Rivera

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Design Team

Anthony Amado

Jazmin Castro, EIT Sebastian Medina, EIT

Justin Parks Albert Larios

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Environmental Team

Paul Stoiber, EIT

Wisam Manlla Jonathan Siu

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11. ATTACHMENTS ● Attachment A - Preliminary Environmental Analysis Report (PEAR) ● Attachment B - Intersection Control Evaluation (ICE) ● Attachment C - Geometric Approval Drawing (GAD) ● Attachment D - Advanced Planning Study (APS) ● Attachment E - Construction Staging Plan

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Project Study Report€¦ · I NT RO DUCT I O N 2 2 . BACKG RO UND 6 3 . P URP O S E AND NE E D 7 4...

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