Congestion Relief Alternative for SR99

SJCOG, in partnership with the City of Ripon, San Joaquin County, Stanislaus County, and California Department of Transportation (Caltrans), is soliciting proposals from qualified consulting firms to evaluate and develop implementable near-, mid- and long-term solutions to address recurring cut-through traffic congestion in the City of Ripon. This congestion is caused by vehicles exiting the state highway system to bypass congestion on SR 99 and SR 120.

Significant congestion on SR 120 and SR 99, combined with the widespread use of navigation applications such as Waze and Google Maps, routinely diverts regional commuter traffic through the City of Ripon. As traffic is dynamically routed to the fastest available path, local streets are increasingly used as cut-through routes. The local streets were not designed to accommodate sustained regional traffic volumes, resulting in localized congestion and community impacts.

Mark Thomas was previously retained to evaluate near-term mitigation measures, Attachment A; however, as documented in prior studies, those measures were not well suited to addressing ongoing commuter diversion. Also, a persistent challenge with any localized mitigation strategy is that it may provide temporary relief in one location by merely shifting traffic issues to other locations.

This RFP seeks to identify solutions that are practical, effective, and capable of advancing toward implementation.

The study will begin after the completion of the SR 99/120 Connector Project Phase 1A, which is anticipated to be completed in summer 2026.

This study will address congestion relief strategies across multiple time horizons:

1. • Near-term (0–2 years)
   • Mid-term (2–7 years)
   • Long-term (beyond 7 years)

A key alternative requiring particular emphasis is the evaluation of a regional transportation bypass that would provide an alternative route for through-traffic, particularly long-distance commuters and freight movement. This bypass would allow vehicles to avoid the most congested segment of SR 99 between Austin Road interchange in Manteca and Main Street interchange in Ripon.

The conceptual regional transportation bypass includes the following corridor alignment:

• A new SR 99 interchange, developed in coordination with the City of Manteca, located between the Jack Tone Interchange and the SR99/120 Interchange.
• The City of Ripon’s proposed Ripon Olive Avenue Expressway, which would allow southbound travel to a proposed Stanislaus River crossing. The Olive Avenue Expressway is included in the City of Ripon’s General Plan and currently located within unincorporated San Joaquin County.
• An extension of the bypass corridor through Stanislaus County to reconnect with SR 99. No planning has been conducted to date for this portion of the corridor.

While the Olive Avenue Expressway is identified as a key long-term component of the City of Ripon’s General Plan, the study must examine alternative or complementary strategies, with the Olive Avenue Expressway bypass as an essential lynchpin that can provide meaningful congestion relief within each time horizon previously identified. The study must also include evaluation of a corridor solution for travel over the Stanislaus River and potential impacts to key roadways in Stanislaus County.

While this RFP presents a generalized scope, proposing firms are encouraged to propose innovative, creative, and/or alternative approaches if there is a “better way” to examine the problem and develop solutions.

The selected consultant will enter into a contract with SJCOG. An example contract is provided as Attachment B.

SR 99 and SR 120 are critical regional corridors serving commuters, goods movement, and local traffic. Over the past several years, increasing traffic volumes have resulted in recurring congestion during peak travel periods. When congestion occurs on SR 99 and SR 120, many drivers rely on navigation applications or local knowledge to seek alternate routes. As a result, traffic diverts from the state highway system onto local streets within Ripon. These local roadways were not designed to accommodate high volumes of regional cut-through traffic. The resulting impacts to the City of Ripon include:

1. • Longer emergency response times
   • Reduced safety for pedestrians, bicyclists and local drivers
   • Increased law enforcement demands for traffic control and vehicle code enforcement
   • Accelerated roadway wear and maintenance needs
   • Increased noise and air pollution in residential neighborhoods

Caltrans does not currently have plans to address this congestion through capacity-increasing improvements on the mainline system. As a result, the issue is being addressed by regional and local partners, with SJCOG taking a lead role while coordinating with Caltrans.

SJCOG is leading the 99/120 Interchange Project, which is being delivered in phases. The first phase termed Phase 1A is currently under construction and is anticipated to be completed in summer 2026. Phase 1A includes:

• Replacement of the Austin Road overcrossing
• Widening SR120 connector ramp to southbound SR99
• Improvements to local streets

Despite these improvements, congestion on the state highway system - and the resulting cut-through traffic through Ripon - is expected to persist.

In 2020, Mark Thomas prepared the Regional Cut-Through Mitigation Memo, which identified 12 potential measures ranging from signal timing modifications to auxiliary lanes and bridge widening. While some measures can be implemented locally with minimal impact, larger-scale solutions require regional coordination with Caltrans. Even then, long-term benefits are constrained by right-of-way limitations along SR 99.

The City of Ripon’s General Plan identifies the Olive Avenue Expressway interchange with SR 99, a future expressway, and an ultimate Stanislaus River crossing into an adjacent county as the long-term solution to relieve regional cut-through traffic. This planned facility is intended to function as a regional bypass and reduce congestion on local streets.

As stated previously, the study will commence following completion of the SR 99/120 Phase 1A construction. The exact time (to start the study) will be submitted by the consultant (within the proposal) based upon their recommendation on the best time to gather the traffic data.