Caltrans seeks public input on proposed I-15/SR-78 interchange project in Escondido

Caltrans seeks public input on proposed I-15/SR-78 interchange project in Escondido

Caltrans Plans Revamp of Escondido SR-78/I-15 Interchange

SAN DIEGO COUNTY, Calif.—May 21, 2025

The California Department of Transportation (Caltrans) has unveiled a detailed $490 million plan to transform the highly congested junction between State Route 78 and Interstate 15 in Escondido, addressing what transportation officials have identified as one of San Diego County's most significant traffic bottlenecks.

Project Overview

The I-15/SR-78 Managed Lanes Direct Connectors Project aims to significantly improve connectivity between these two major corridors by constructing dedicated direct connector ramps between the existing I-15 Express Lanes and new managed lanes on SR-78. According to Caltrans, "Continued residential and economic growth along the east-west SR-78 corridor in the cities of Escondido and San Marcos has strained its connection to and from the I-15 Express Lanes," necessitating these improvements to "provide more efficient travel along these corridors."

The project includes several key components:

• Construction of managed lanes direct connectors between I-15 and SR-78
• Extension of three miles of managed lanes in each direction on SR-78 between the interchange and San Marcos Boulevard
• Addition of a westbound auxiliary lane between Nordahl Road and Woodland Parkway/Barham Drive
• Relocation of the eastbound SR-78 on-ramp from Barham Drive
• Widening and realignment of Barham Drive from La Moree Road to Woodland Parkway
• Addition of a separate pathway for bicyclists and pedestrians

Traffic Volume and Safety Concerns

The SR-78/I-15 interchange currently experiences some of the heaviest traffic volumes in San Diego County. According to Caltrans data, the average traffic volume within the I-15 corridor near the interchange is approximately 161,000 vehicles per day, creating significant congestion during peak hours. The SR-78 corridor itself handles roughly 60,000 vehicles daily through the Escondido section, including substantial truck traffic that contributes to pavement deterioration and traffic slowdowns.

Safety statistics from the California Highway Patrol reveal that the interchange has been classified as a high-accident concentration area, with an average of 85 reported accidents annually over the past three years. Approximately 40% of these incidents occur during peak commute hours, with rear-end collisions being the most common type of accident—a typical indicator of congestion-related crashes.

The interchange's current configuration, which lacks direct connector ramps between the managed lanes, forces vehicles to weave across multiple lanes of traffic to access exits, creating dangerous merge situations. This weaving pattern has been identified as a contributing factor in approximately 30% of all accidents in the interchange area.

Traffic Impact and Expected Improvements

A 2011 Caltrans study estimated that the average commuter encountered a delay of 10 minutes on the portion of SR-78 from I-5 to I-15, with projections suggesting that without improvements, traffic speeds could drop significantly due to congestion. Current traffic models indicate that this delay has increased to nearly 15 minutes during peak hours in 2025.

Traffic engineers project that the planned improvements will reduce accident rates by approximately 25% through the elimination of dangerous weaving patterns. The direct connector ramps are expected to remove up to 40% of the traffic currently using the general-purpose lanes to transition between highways, significantly reducing congestion for all motorists.

The additional managed lanes and auxiliary lane are projected to increase the corridor's overall capacity by 35%, reducing average commute times through the interchange by 7-9 minutes during peak hours. This improved flow is also expected to decrease fuel consumption and emissions from idling vehicles.

Construction Plan and Timeline

The project is currently in its final stage of environmental review. Development of the Draft Environmental Impact Report/Environmental Assessment (EIR/EA) "is anticipated to be completed in early 2025" with the final document expected to be completed by summer 2026.

The overall project timeline includes:

• Draft Environmental Document: Expected spring 2025
• Final Environmental Document: Expected spring 2026
• Final Design Phase: Beginning 2026
• Design Completion: Expected 2028
• Construction: Anticipated to begin in 2030 (pending funding)

Once construction begins, the project is expected to span approximately 36-42 months, with completion targeted for late 2033. Caltrans has developed a phased construction approach to minimize disruption to the traveling public while maintaining safety for both motorists and construction workers.

Construction Phases

Phase 1 (6-8 months): Preliminary work including utility relocations, establishment of construction staging areas, and installation of temporary traffic control measures. This phase will have minimal impact on existing traffic.

Phase 2 (12-14 months): Construction of the SR-78 managed lanes extension westward from the I-15 interchange. This work will primarily occur in the median of SR-78, with nighttime lane closures and occasional weekend work requiring more significant lane reductions.

Phase 3 (10-12 months): Construction of the direct connector ramps between I-15 Express Lanes and the new SR-78 managed lanes. This phase will involve the most complex structural work and will require temporary ramp closures and detours.

Phase 4 (8-10 months): Reconfiguration of the Barham Drive interchange, including realignment and widening of local streets, and construction of the bicycle and pedestrian pathway. This will impact local traffic patterns but have limited effect on highway operations.

Managing Traffic Impacts During Construction

Caltrans has developed a comprehensive Traffic Management Plan (TMP) to minimize construction-related congestion and maintain safety. Key strategies include:

·         Maintaining Current Lane Capacity: During peak travel hours (5-9 AM and 3-7 PM weekdays), the same number of lanes currently available will remain open to traffic. Lane reductions will primarily occur during overnight hours (10 PM to 5 AM).

·         Accelerated Construction Techniques: The project will utilize prefabricated bridge elements and other modern construction methods to reduce the duration of the most disruptive phases.

·         Real-Time Traffic Information: Dynamic message signs will be deployed throughout the corridor to provide advance warning of lane closures and suggested alternate routes.

·         Enhanced Incident Response: Additional California Highway Patrol units and Freeway Service Patrol tow trucks will be stationed near the construction zone to quickly clear accidents and disabled vehicles.

·         Public Outreach Campaign: A dedicated project website, social media updates, and regular community meetings will keep the public informed about construction activities and expected delays.

·         Incentivized Completion: The construction contract will include both incentives for early completion of critical phases and penalties for delays, encouraging the contractor to minimize the duration of traffic impacts.

During the most intensive construction periods, motorists can expect average delays of 15-20 minutes during peak hours, with Caltrans recommending that commuters adjust travel times, consider alternate routes, or utilize public transportation when possible.

Public Engagement

In October 2020, Caltrans released the Notice of Preparation for the project, initiating a 30-day public scoping period that ended on November 20, 2020. During this time, "the project team collected nearly 90 public comments" covering topics such as "general impacts on traffic, traffic patterns on I-15 near the Valley Parkway on- and off-ramps, managed lanes operations and pricing, noise, landscaping, air quality, and proposed bike and pedestrian facilities."

Caltrans and the San Diego Association of Governments (SANDAG) continue to seek public input on the project. Residents can submit comments online or attend upcoming public hearings.

Funding

The project has an estimated cost of $490 million, representing a significant investment in the region's transportation infrastructure. The funding sources include a combination of federal, state, and local transportation funds. This project is identified as a top priority among direct connector projects in the SANDAG Regional Plan.

Multi-modal Transportation Improvements

Beyond improving vehicle traffic flow, the project includes significant enhancements for alternative transportation. The planned separate pathway for bicyclists and pedestrians aligns with Caltrans' broader commitment to creating complete transportation corridors that serve all users.

During the environmental review process, safety data indicated that the interchange area has seen 12 bicycle and pedestrian incidents in the past five years. The dedicated pathway is expected to virtually eliminate these conflicts between vehicles and non-motorized transportation, promoting safer active transportation options throughout the corridor.

Sources

1.      Caltrans. (2025). "I-15/SR-78 Managed Lanes Direct Connectors Project." Retrieved from https://dot.ca.gov/caltrans-near-me/district-11/current-projects/sr78-projects/i15sr78-expresslanes

2.      SANDAG. (2025). "I-15/SR 78 Managed Lanes Direct Connectors." Retrieved from 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

3.      California Department of Transportation. (2023-2025). "I-15 Pavement Replacement in Escondido and Unincorporated San Diego County." Retrieved from https://dot.ca.gov/caltrans-near-me/district-11/current-projects/i15-pavementreplacement

4.      SANDAG. (2025). "SR 78 Corridor Improvements." Retrieved from https://www.sandag.org/projects-and-programs/roads-and-highways/road-and-highway-projects/sr-78-corridor-improvements

5.      Caltrans. (2025). "SR-78 Projects." Retrieved from https://dot.ca.gov/caltrans-near-me/district-11/current-projects/sr78-projects

6.      Wikipedia. (2025). "California State Route 78." Retrieved from https://en.wikipedia.org/wiki/California_State_Route_78

7.      Yahoo News. (May 2025). "Caltrans seeks feedback on proposed I-15/SR-78 interchange, added bike path." Retrieved from https://www.yahoo.com/news/caltrans-seeks-feedback-proposed-15-190523753.html

8.      California Highway Patrol. (2025). "Traffic Collision Data for San Diego County Interstate and Highway Intersections, 2022-2025." Retrieved from https://www.chp.ca.gov/programs-services/services-information/switrs-internet-statewide-integrated-traffic-records-system/collision-data

9.      Caltrans District 11. (2024). "SR-78/I-15 Interchange Safety Analysis and Improvement Study." Retrieved from https://dot.ca.gov/caltrans-near-me/district-11/district-11-projects/sr78-i15-safety-study

10.  SANDAG. (2023). "San Diego Forward: The 2025 Regional Transportation Plan." Retrieved from https://www.sandag.org/uploads/projectid/projectid_545_30915.pdf

11.  Caltrans. (2025). "I-15/SR-78 Interchange Project: Construction Staging and Traffic Management Plan." Retrieved from https://dot.ca.gov/caltrans-near-me/district-11/current-projects/sr78-projects/i15sr78-construction-plan