Recommended improvements

The Patterson Planning Commission covered a robust Transportation Infrastructure Master Plan (TIMP) presented by city staff and consultant Christopher Thnay of Advanced Mobility Group (AMG).

The plan introduced a guide to identify infrastructure problem areas and present a roadmap for how the City of Patterson will handle short-term and long-term infrastructure plans to alleviate issues that may arise due to future growth.

After some lengthy discussion and deliberation, the three Planning Commission members present (Chairman Ron West, Commissioner Eric Bendix, and Commissioner Titus Linares) agreed to forward the TIMP to the Patterson City Council for further review with four recommendations to consider.

The Planning Commission proposed that:

  • Roundabouts are standard practice for every intersection it is applicable
  • The council review concerns about a new bridge over the San Joaquin River
  • The council review concerns about the proposed South County Corridor Freeway alignment
  • That potential future improvements to Zacharias Road include plans to have a grade separation or flyover above Highway 33 and the railroad to aid traffic flow.

Many of these plans, such as the South County Corridor and improvements to Zacharias Road as part of the new alignment, are decades away from becoming a reality for Patterson residents.

Since these major infrastructure projects that involve Cal-Trans and Stanislaus County are potentially years or decades away, the Transportation Infrastructure Master Plan does not depend on these projects to help alleviate traffic issues in Patterson.

Study recommendations

Overall the study produced seven recommendations for city officials to consider:

  • Complete Interstate 5/Sperry Avenue Interchange Improvements-a comprehensive evaluation under CalTrans is currently underway. An improved interchange would provide very significant improvement to the city’s major gateway to the I-5 freeway.
  • Improve Sperry Avenue to four lanes-currently several segments are two lanes, including east of Ward Avenue to Highway 33 and west of Baldwin Road. A complete four-lane Sperry Avenue would add significant capacity to the major east-west arterial street in the city.
  • Create an advanced Traffic Management System (ATMS) and develop Traffic Signal Master Plan- an ATMS system would allow the city to effectively manage the city’s traffic signals, services other modes of travel and improve safety.
  • Whenever it is feasible, use roundabouts in place of traffic signals.
  • Establish and provide Complete Street policies for all future roadways. Adopt the recommended bike facilities plan and provide future funding for its construction. The creation of more continuous bike lanes at key destinations would encourage more people to use bikes instead of autos.
  • Focus on the redesign of downtown streets based on walkable and livable principles.
  • Initiate process to plan and fund the future I-5/Zacharias interchange.

Problematic Intersections

Three intersections were identified as problem areas that the city must address to relieve traffic congestion at the Sperry Avenue and Interstate 5 off interchange, the junction of Sperry Avenue and Highway 33, and Rogers Road and Highway 33.

The issues that exist at Sperry Avenue and Interstate 5, as detailed in a previous Irrigator article, must involve Cal-Trans and Stanislaus County because it is outside of the City of Patterson’s jurisdiction. The intersection is due to get STOP signs to stop traffic flow on Sperry Avenue to allow for cars on the southbound off-ramp to exit the freeway at a better pace. Still, the interchange will ideally undergo a more drastic makeover in the years to come to alleviate the traffic issues.

A 10-year intersection improvement cost estimate proposed by the report stated that the improvements to 17 intersections across the city could cost an estimated $26,524,892.

The Interstate 5 interchange represented the bulk of the cost ranging from $11.3-14.6 million. This estimate includes a 25 percent contingency. The estimate used for the I-5 interchange was taken from an April 20, 2017 study.

Each intersection was graded based on the models used to calculate the congestion. The 10-year scenario assumed a population of approximately 28,900 residents and 21,980 jobs in Patterson.

These models attached a letter grade running from A to F for each intersection. All of the problematic intersections mentioned received a grade of E or lower during a.m. or p.m. peak hours.

The master plan’s goal is to have each intersection in the city have a rating of D or higher in the short term and long term future. Anything below a D rating is considered unacceptable by limits set by the city.

Commission advocates for roundabouts

Chairman West and Commissioners Bendix and Linares all agreed that roundabouts would be a preferable solution because it would result in lower crash frequencies, crash severity and errors, and better efficiency. It would also potentially save $5,000 per year per intersection in electricity and maintenance costs. Traffic signals would cost an estimated $300,000 to install. Roundabouts can be installed at a much lower price and reduce expenses on maintenance.

Other benefits of roundabouts over intersections as detailed in the report include:

  • Decrease crashes by 39 percent
  • Crashes involving injuries decrease by 76 percent
  • Crashes involving fatalities or incapacitating injuries drop by 90 percent
  • Vehicle delay was reduced by 62-74 percent, resulting in savings of 325,000 hours of motorists time annually based on 10 locations studied
  • Reduction in fuel consumption of 235,000 gallons annually
  • Environment benefits of reduction in vehicle emissions

Roundabouts may not be the “best solution at all locations,” according to the study. Still, the commission agreed that they should be implemented whenever possible to take advantage of its cost-effectiveness and general superiority at allowing traffic flow.

Long term buildout costs

While 10-year short term costs were addressed, the report also extensively covers the estimated outlook and cost of roadway improvements in the long term.

“It is estimated that major roadway improvements would be required to accommodate the projected traffic growth due to buildout land use in the future. In general, it could be assumed four-lane roads would be required for all the major north-south and east-west arterials,” the report read. “Improvements, in general, will be roadway widening to add lanes, new traffic signal installations (or roundabouts), and additional improvements to accommodate pedestrian and bicycle use.”

The long term study noted that it’s findings assumed that major improvements contemplated at the Sperry Avenue and Interstate 5 interchange and new interchange at I-5 and Zacharias Road would both be implemented in the future. The proposed South County Corridor was assumed to be aligned generally along West Main Avenue, Eucalyptus Avenue and Zacharias. This was in line with the South County Corridor Feasibility Study adopted.

Long term buildout improvement costs totaled $213,826,569 for local segments. The Sperry Avenue and I-5 interchange were again estimated at $11.3-14.6 million. The Zacharias and I-5 interchange were estimated at $75 million, and the South County Corridor-Sperry Avenue realignment was estimated at $266 million. It was made clear that these are long term estimates. The funds to cover the costs are not expected to be needed now or even potentially in the short term future, but rather these estimates could be years if not decades away. The study is a long term outlook on spending.

Advanced Traffic Management System

As detailed in the report, it was recommended by AMG Consultant Thnay that Patterson implement an Advanced Traffic Management System to help aid the city in monitoring roadways and traffic conditions.

The system would aid Patterson in traffic flow by giving smarter signal times to intersections that are using a light signal in the city. An example used was that if traffic is heavy at a fixed signal, the signal will still only offer a finite amount of green light time before changing regardless of the traffic context. An adaptive system such as the ATMS, would recognize the congestion and offer more green light time to help relieve the back-up.

PI reporter

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