Major Highway Construction to Impact San Diego Commutes for Next Four Years

$623 million in freeway improvements will create significant traffic disruptions across I-5, I-805, and SR-78 corridors

SAN DIEGO — Brace yourself for years of construction headaches. San Diego County drivers are about to experience the largest freeway construction program since these highways were first built, with $623 million in improvements starting this fall across Interstate 5, Interstate 805, and State Route 78.

The massive undertaking will touch virtually every major north-south and east-west route in the county, promising smoother roads and better traffic flow — but only after drivers endure significant traffic disruptions, including lane closures and full weekend highway shutdowns throughout the construction period.

"Over the next two years, we ask for motorists' patience," Ann Fox, Caltrans District 11 director, told NBC 7 on Friday during a ceremonial groundbreaking. By the end of fall, the various projects will all be happening at once, according to Caltrans.

What Drivers Can Expect

The construction blitz will unfold in waves across San Diego's busiest corridors:

Interstate 5: $113.7 million to restore I-5 to a state of good repair and improve ride quality from Camino De La Plaza in Chula Vista to 0.3 mile south of Via De La Valle in north San Diego. This 30-mile stretch serves hundreds of thousands of daily commuters.

State Route 78: $126 million to enhance a 17.7-mile stretch of SR-78, from Interstate 5 in Oceanside to Broadway and Lincoln Parkway in Escondido. Much of this work builds on ongoing culvert and drainage repairs that began in February 2023 and should conclude by mid-2025.

Interstate 805: The biggest headache for drivers, with three separate projects totaling over $380 million. $222.5 million to improve pavement conditions and upgrade infrastructure along a 14.5-mile stretch of I-805 in the cities of San Diego, Chula Vista, and National City from the San Ysidro Port of Entry to SR-15, plus additional work extending north to the I-5 merge.

Most projects are expected to finish next year, with the exception of the major I-805 construction, which could last two to four years.

The SR-78/I-15 Wild Card

While the immediate construction focuses on road repairs, an even bigger project looms on the horizon that will reshape North County commuting. The $450 million I-15/SR-78 Managed Lanes Direct Connectors project would create direct freeway-to-freeway connections between the two highways, eliminating the current bottleneck where drivers must navigate surface streets and traffic lights.

Construction is anticipated to begin in 2030, pending funding, but the environmental review process is heating up now. A public hearing will be held at the City of San Marcos Civic Center at 3 Civic Center Drive, San Marcos, CA 92069, on Thursday, June 5, from 6:00 p.m. to 7:30 p.m.

For drivers who regularly use the SR-78/I-15 interchange in Escondido — where a 2011 Caltrans study estimated that the average commuter encountered a delay of 10 minutes on the portion from I-5 to I-15 — this project could dramatically improve travel times once completed.

What This Means for Your Commute

The construction timing creates a perfect storm of traffic impacts. "You'll see that construction happening along Interstate 805, you'll see signs talking about future work coming up on ramps up and down the I-5 corridor. We do have some early work that will start along state Route 78," Fox said.

Orange construction signs are already visible on I-805 and SR-78, alerting drivers to upcoming work zones.

For SR-78 Commuters: Night work will be implemented in areas requiring pipe replacement from 9 pm to 5 am, which should minimize daytime impacts. However, weekend closures and lane restrictions are expected as the broader $126 million improvement project ramps up.

For I-805 Users: Prepare for the longest disruption. The nearly quarter-billion-dollar reconstruction will stretch from the Mexican border to central San Diego, affecting everything from daily commutes to border crossings and airport access.

For I-5 Drivers: The rehabilitation work covers the entire county from Chula Vista to Del Mar, impacting both local commuters and long-distance travelers between San Diego and Orange County.

The Upside: Better Roads Ahead

Despite the short-term pain, drivers will eventually benefit from significantly improved infrastructure. The construction includes safety upgrades such as improved electronic signage and lighting systems, along with upgraded traffic management system assets that should reduce accidents and improve traffic flow.

The I-805 projects alone will include rehabilitating existing culvert systems, replacing roadside signs, and overhead signs, upgrading midwest guardrail systems, planting work, paving beyond the gore areas, paving narrow areas, slope paving, installing mast arm ramp meters, upgrading and installing various ITS elements.

"The biggest intent is to save what we have, to preserve and maintain and keep it longer-lasting, to give it a longer life. A lot of our roadways are getting to their life expectancy, and so we're just trying to fix it first and get it before it fails," said Karen Jewel, project corridor director for the central corridors at Caltrans District 11.

Planning Ahead

Caltrans promises to provide advance notice of major closures and detours. Fox emphasized that as closures happen, communities that are impacted will be notified in advance of detours and construction.

For real-time updates, drivers should monitor Caltrans' QuickMap app and follow @SDCaltrans on social media for the latest construction alerts and traffic conditions.

The agency is also encouraging flexible work arrangements and alternative transportation during peak construction periods. As one rideshare driver noted, while the construction will initially slow down trips, "on the flipside of it, it's going to help us with the maintenance of our vehicles," since smoother roads mean less wear and tear.

The message for San Diego drivers is clear: the next few years will test your patience, but the investment should pay dividends for decades to come.

Caltrans begins $623 million of work to improve I-5, I-805, Route 78

Road Quality Decline: analysis reveals concerning trends in pavement conditions. The City of San Diego's road network scored 63 points on the Pavement Condition Index in 2023, down from 71 in 2016. This represents a decline from "Satisfactory" to "Fair" condition over just seven years.

Measurement Standards: The Pavement Condition Index (PCI) is measured on a scale of 0 to 100 (where 100 means a newly paved road), and many factors affect a city's or county's PCI score including pavement age, climate and precipitation, traffic loads and available maintenance funding. Each segment of road is evaluated based on ride quality, cracking, and signs of pavement distress using specialized vehicles with inertial profilers, transverse laser system, and high resolution cameras.

Financial Reality: Achieving the target PCI of 70 requires dedicated annual investments totaling $1.9 billion over the next decade, highlighting the massive scale of deferred maintenance that has accumulated over decades.

CALTRANS San Diego County Highway Infrastructure Engineering Report

Interstate 5, State Route 78, and Interstate 805 Improvement Projects

Executive Summary

CALTRANS District 11 has initiated the largest freeway investment program in San Diego County since the original construction of these highways in the 1960s and 1970s. The program encompasses $623 million in state and federal funding across five major projects targeting the region's most heavily traveled corridors: Interstate 5, Interstate 805, and State Route 78. These projects represent a comprehensive "Fix It First" strategy focused on pavement rehabilitation, infrastructure preservation, and traffic management system upgrades.

The timing and scope of these projects will create significant coordination challenges and traffic impacts, particularly at critical interchange points including the SR-78/I-15 connection where a separate $450 million managed lanes project is concurrently under development.

Project Overview and Scope

Interstate 5 Corridor Projects

I-5 South Segment Rehabilitation

Investment: $113.7 million
Scope: Pavement rehabilitation from Camino De La Plaza (Chula Vista) to 0.3 miles south of Via De La Valle (Del Mar)
Objectives: Restore pavement to state of good repair, improve ride quality, reduce maintenance interruptions, and extend pavement service life
Timeline: Construction initiated Fall 2025, completion expected 2026-2027

The I-5 project addresses critical infrastructure needs along one of California's most heavily trafficked corridors. The 30+ mile segment serves as the primary north-south transportation artery connecting San Diego County to Orange County and beyond.

State Route 78 Corridor Projects

SR-78 Primary Enhancement Project

Investment: $126 million
Scope: 17.7-mile corridor improvement from I-5 (Oceanside) to Broadway and Lincoln Parkway (Escondido)
Timeline: Multi-phase implementation through 2025-2026

SR-78 Culvert and Road Rehabilitation Project

Investment: Estimated $20-35 million (ongoing)
Scope: Rehabilitation of 35 aging culverts between I-5 and I-15, including drainage infrastructure and pavement improvements
Current Status: Construction began February 2023, completion scheduled mid-2025
Technical Features:

Cured-In-Place Pipe liner installation
Pipe invert paving to eliminate open excavation
Night work implementation (9 PM to 5 AM) for pipe replacement
Resurfacing at El Camino Real overcrossing

SR-78 Asset Management Project

Investment: $133 million planned
Scope: Pavement resurfacing, bridge rail improvements, ADA compliance upgrades, culvert restoration
Key Feature: New westbound auxiliary lane between Nordahl and Twin Oaks Valley roads in San Marcos

Interstate 805 Corridor Projects

The I-805 corridor represents the largest single investment in the program with three coordinated projects:

I-805 South Pavement Rehabilitation and Asset Management

Investment: $222.5 million
Scope: 14.5-mile segment from San Ysidro Port of Entry to SR-15 interchange
Timeline: 2025-2029 (extended timeline due to project complexity)
Technical Scope:

Full pavement grinding and lane replacement
Individual concrete slab replacement
Ramp rehabilitation and shoulder improvements
Culvert system rehabilitation
ITS (Intelligent Transportation Systems) upgrades
Mast arm ramp meter installation

I-805 Central Corridor Improvements

Investment: $107 million
Scope: 9-mile segment from SR-15 interchange to north of SR-52 interchange
Focus: Infrastructure improvements and traffic management system upgrades

I-805 North Asset Management

Investment: $53 million
Scope: 4.8-mile segment from north of SR-52 interchange to I-5/I-805 separation
Emphasis: Drainage culvert improvements and asset management

SR-78/I-15 Interchange Interaction Analysis

I-15/SR-78 Managed Lanes Direct Connectors Project

Project Overview

Investment: $450 million estimated cost
Current Status: Environmental review phase (Draft EIR/EA released May 19, 2025)
Public Comment Period: Through July 3, 2025
Timeline:

Final Environmental Document: Summer 2026
Design Phase: 2026-2028
Construction: 2030-2033 (pending funding)

Technical Scope

Extension of 3 miles of managed lanes in each direction on SR-78 between I-15 interchange and San Marcos Boulevard
Direct connector construction between SR-78 managed lanes and I-15 express lanes
Westbound auxiliary lane addition between Nordahl Road and Woodland Parkway/Barham Drive
Relocation of eastbound SR-78 on-ramp from Barham Drive
Widening and realignment of Barham Drive from La Moree Road to Woodland Parkway

Coordination Challenges and Traffic Impact Assessment

Critical Interaction Points

1. SR-78 Corridor Confluence: The simultaneous execution of multiple SR-78 projects creates compounding effects:

Ongoing culvert rehabilitation work intersects with asset management projects
I-15 interchange improvements will occur during active SR-78 construction phases
Managed lanes construction will require coordination with existing pavement rehabilitation

2. I-15 Pavement Replacement Coordination:

Current Project: $71.7 million I-15 pavement replacement between SR-78 and Deer Springs Road
Status: Construction began February 2023, completion Summer 2025
Impact: Directly affects SR-78/I-15 interchange access during critical construction periods

3. Traffic Diversion Patterns:

SR-78 serves as primary east-west corridor with 161,000+ vehicles daily through project limits
I-15 managed lanes project will create temporary capacity constraints
Coordinated closures planned to minimize cumulative impacts

Projected Traffic Management Strategies

Extended weekend highway shutdowns during critical construction phases
Coordinated night work schedules (9 PM to 5 AM) across multiple projects
Implementation of temporary traffic management systems
Enhanced incident management protocols during construction

Engineering and Technical Considerations

Pavement Technology Implementation

Continuously Reinforced Concrete Pavement (CRCP)

Implemented on I-15 segment adjacent to SR-78 interchange
40-year expected lifespan
Superior load-bearing capacity for heavy traffic volumes
Integration with SR-78 managed lanes construction

Advanced Drainage Systems

High-density plastic and concrete pipe replacement for corrugated steel systems
Enhanced capacity to handle increased stormwater from climate change impacts
Coordinated installation across SR-78 corridor to prevent future excavation conflicts

Intelligent Transportation Systems (ITS) Integration

Traffic Management Enhancements

Vehicle-to-Infrastructure (V2I) technology deployment
Advanced electronic signage and lighting systems
Real-time traffic monitoring and incident management
Coordinated signal timing optimization across corridor intersections

Funding and Regulatory Framework

Funding Sources

Federal Infrastructure Investment and Jobs Act: Primary funding mechanism
State Highway Operation and Protection Program (SHOPP)
Senate Bill 1 (Road Repair and Accountability Act of 2017)
SANDAG TransNet local funding contributions
Total San Diego County allocation: Nearly $62 billion in federal infrastructure funding

Environmental Compliance

California Environmental Quality Act (CEQA) compliance across all projects
National Environmental Policy Act (NEPA) requirements for federal funding
Coordination with Buena Vista Lagoon Restoration project (I-5/SR-78 interchange)
Community impact assessments and public engagement protocols

Risk Assessment and Mitigation Strategies

Construction Risk Factors

Weather Dependencies: Previous SR-78 culvert work experienced four extensions due to storm conditions
Traffic Volume Management: 161,000+ daily vehicles on SR-78 requiring careful staging
Coordination Complexity: Five major concurrent projects across interconnected highway system
Funding Contingencies: Several projects await funding approval for later phases

Mitigation Protocols

Advanced public notification systems for closures and detours
Coordinated construction scheduling to minimize simultaneous impacts
Enhanced emergency response protocols during construction
Real-time traffic monitoring and adaptive management strategies

Project Timeline and Coordination Matrix

Project	Start Date	Completion	Critical Coordination Points
SR-78 Culvert Rehabilitation	Feb 2023	Mid-2025	Overlaps with I-15 pavement completion
I-15 Pavement Replacement	Feb 2023	Summer 2025	Direct interchange impact
I-5 South Rehabilitation	Fall 2025	2026-2027	Affects SR-78 western terminus
I-805 South Rehabilitation	2025	2029	Connects to I-15 interchange area
I-15/SR-78 Managed Lanes	2030	2033	Post-rehabilitation construction

Recommendations and Conclusion

The scale and scope of these concurrent infrastructure improvements represent both an unprecedented opportunity and a significant logistical challenge for San Diego County's transportation network. Successful implementation requires:

Enhanced Coordination Protocols: Real-time communication between project teams to minimize cumulative traffic impacts
Adaptive Traffic Management: Dynamic routing and signal optimization during construction phases
Public Communication Strategy: Comprehensive advance notification and alternative route guidance
Contingency Planning: Preparation for weather delays and unforeseen coordination conflicts

The SR-78/I-15 interchange improvements, while not beginning construction until 2030, must be designed with full consideration of the infrastructure modifications occurring throughout the corridor between 2025-2029. The success of this program will establish San Diego County's highway system for decades of future growth while minimizing disruption during the critical construction period.

Source Documentation and Citations

1. Caltrans District 11. "Draft EIR for I-15/SR-78 Interchange Released for Public Review and Comment." Press Release, May 19, 2025. https://dot.ca.gov/caltrans-near-me/district-11/news

2. Caltrans District 11. "I-15/SR-78 Managed Lanes Direct Connectors and Woodland Parkway Interchange Project." Project Documentation, 2025. https://dot.ca.gov/caltrans-near-me/district-11/current-projects/sr78-projects/i15sr78-expresslanes

3. Caltrans District 11. "I-5/SR-78 Interchange Project." Project Information, 2025. https://dot.ca.gov/caltrans-near-me/district-11/current-projects/sr78-projects/i5sr78-interchange

4. Caltrans District 11. "I-805 South Pavement Rehabilitation and Asset Management Project." Project Details, 2025. https://dot.ca.gov/caltrans-near-me/district-11/current-projects/i805s-pavrehab

5. Caltrans District 11. "I-805/SR-15 Transit Only Connector and Managed Lanes Project." Project Overview, 2025. https://dot.ca.gov/caltrans-near-me/district-11/current-projects/i805sr15-transitonly-managedlanes

6. Caltrans District 11. "State Route 78 Culvert & Road Rehabilitation Project." Project Status, 2025. https://dot.ca.gov/caltrans-near-me/district-11/current-projects/sr78-projects/sr78rehab

7. Caltrans District 11. "SR-78 Asset Management Project." Project Information, 2025. https://dot.ca.gov/caltrans-near-me/district-11/current-projects/sr78-projects/sr78-assetmanagement

8. Jennewein, Chris. "Caltrans begins $623 million of work to improve I-5, I-805 and Route 78." Times of San Diego, May 31, 2025. https://timesofsandiego.com/politics/2025/05/31/caltrans-begins-work-improve-freeways/

9. NBC 7 San Diego. "Caltrans begins projects across San Diego freeways, state routes." May 29, 2025. https://www.nbcsandiego.com/news/local/caltran-projects-across-san-diego-freeways-state-routes/3837259/

10. Orange County Transportation Authority. "I-5 Freeway Improvement Project from the San Diego County Line to Avenida Pico." Project Overview, 2025. https://www.octa.net/programs-projects/projects/freeway-projects/i-5-county-line-to-avenida-pico/overview/

11. San Diego Association of Governments (SANDAG). "I-15/SR 78 Managed Lanes Direct Connectors." Project Information, 2025. https://www.sandag.org/projects-and-programs/roads-and-highways/road-and-highway-projects/sr-78-corridor-improvements/i-15-sr-78-managed-lanes-direct-connectors

12. San Diego Association of Governments (SANDAG). "I-5/SR 78 Interchange Improvements." Project Details, 2025. https://www.sandag.org/projects-and-programs/roads-and-highways/road-and-highway-projects/sr-78-corridor-improvements/i-5-sr-78-interchange-improvements

13. San Diego Association of Governments (SANDAG). "SR 78 Corridor Improvements." Program Overview, 2025. https://www.sandag.org/projects-and-programs/roads-and-highways/road-and-highway-projects/sr-78-corridor-improvements

14. TransNet - KeepSanDiegoMoving.com. "I-5 Corridor." Project Information, 2025. https://www.keepsandiegomoving.com/i-5-corridor/Hwy-Impr-Intro.aspx

15. Wikipedia. "California State Route 78." Updated March 5, 2025. https://en.wikipedia.org/wiki/California_State_Route_78

Report prepared: June 1, 2025
Document Classification: Public Infrastructure Analysis
Contact: SR78@KeepSanDiegoMoving.com for project-specific inquiries

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