Recent accident history in Sutter County was researched to identify primary accident factors and high accident locations. The purpose of this investigation was to identify any problems that may be addressed within the scope of the transportation planning for the General Plan, which may lead to identification of general goals for safety improvement on County roads. This is not a detailed traffic engineering study of County road accidents.

The accident history for roadways between 1990 and 1994 were obtained from the Statewide Integrated Traffic Record System (SWITRS). SWITRS does not include accident information for streets within the jurisdictions of the Cities of Yuba City and Live Oak and/or information on state highways. Table 4.8-1 summarizes the accident types for the five year period and Table 4.8-2 lists the intersection locations with six or more accidents within 200 feet for years 1990 through 1992.

TABLE 4.8-1
COUNTY ROAD ACCIDENT SUMMARY

As indicated by Table 4.8-1, Sutter County experienced a high of 283 total accidents in 1990 with nine (9) accidents involving a fatality and a low of 244 total accidents during 1993 of which five (5) involved a fatality.

TABLE 4.8-2
INTERSECTIONS WITH SIX OR MORE ACCIDENTS IN 1990 - 1992

As shown in Table 4.8-2, the highest accident locations averaged between two (2) to three (3) accidents per year. The majority of accidents at the intersections were broadside, reflecting conflicts in right-of-way. A closer inspection of the individual intersection locations should be performed to identify potential improvements in intersection controls.

4.9 FUTURE TRAFFIC CONDITIONS AND IMPROVEMENT REQUIREMENTS

In order to generate traffic data for this report, reasonable population and growth projections were needed for the County. As such, SACOG population data has been utilized for modeling purposes. The population projections from SACOG include assumptions about future growth throughout the County, with major growth projected in the Yuba City Urban Area.

PROPOSED AND PLANNED DEVELOPMENTS AND TRANSPORTATION PROJECTS IN ADJACENT JURISDICTIONS

Sutter County is surrounded by six counties, including Yuba, Placer, Sacramento, Yolo, Colusa and Butte Counties. In addition, directly across the Feather River to the east is the City of Marysville. Major development in any one of these jurisdictions could affect travel demand and road improvement requirements on the Sutter County street system. Yuba and Placer Counties are the only two counties which have active major development projects that could influence travel demand on the Sutter County street system. No other major development or circulation improvement proposals are planned in other adjacent jurisdictions.

In Yuba County, several development projects have been proposed and approved to various stages which could add to cumulative traffic on Highways 99 and 70. The Plumas Lake specific plan was approved in September of 1993 and would result in some 11,750 dwelling units at build-out. Plumas Lake is located in the vicinity of the proposed third bridge crossing between Sutter and Yuba Counties. Additionally, specific plans have been approved for: East Linda - 5,500 dwelling units,

114 acres of commercial; Spring Valley - 3,503 dwelling units; and, River Highlands - 9,372 dwelling units. Very little development has occurred in any of these specific plan areas and is not expected to occur until the economy rebounds. Additionally, significant service and facilities improvements will be required for most of these areas to develop.

Placer County completed an update of its general plan in August of 1994 and no new major developments were proposed near Sutter County. A large project which could affect State Route 99/70 is the Twelve Bridges development. This project has been annexed to the city of Lincoln and will include a variety of land uses, including several thousand dwelling units, as well as an expansion of the Sierra College campus. Additionally, a West Placer Specific Plan is under discussion for land directly east of the Sutter County line, with the north boundary of the plan area Baseline Road (the extension of Sutter County's Riego Road) and the south boundary the Sacramento County line. While no formal application has been submitted as of February 1996, it is anticipated that the specific plan will proceed, encompassing 5,000 acres and providing up to 14,000 dwelling units.

In addition to the planned third bridge crossing of the Feather River, identified in the State Route 70 and State Route 99 Corridor Study, July, 1990, is a fourth bridge crossing proposal north of the existing bridges. It is not anticipated that this fourth bridge crossing will be significantly contemplated until the third bridge crossing is constructed.

TRAFFIC PROJECTIONS AND CIRCULATION IMPROVEMENT REQUIREMENTS

The 2015 future traffic projections were determined using travel demand forecasting models. These traffic models (PM peak hour and daily traffic flows) were developed by OMNI-MEANS for the Bi-County Transportation Agency as a part of the state mandated Congestion Management Program for Sutter and Yuba Counties. Since the preparation of the initial Congestion Management Program Study, conducted in 1991, the models have subsequently been updated and used for the Yuba County Traffic Impact Fee Study, the Sutter County/Yuba City Traffic Impact Fee Study and the 1993 Congestion Management Program Update, all conducted by OMNI-MEANS.

Concurrent with the use of the Sutter/Yuba Counties traffic models developed by OMNI-MEANS, Caltrans also commissioned the development of traffic models for the same area, but forecasting to the year 2020. This new Caltrans model similarly uses the MINUTP software and results in generally consistent traffic projections for likely increased travel demand ten years hence.

The travel demand forecasting models used perform the traditional travel demand forecasting procedure, but facilitate these procedures on a personal computer. This allows for rapid testing of land use scenarios and street system alternatives. The traditional forecasting procedure consists of trip generation, trip distribution and trip assignment. Trip generation is the quantification of the amount of traffic generated by applying a trip rate, normally taken from publications of standard trip rates, to the land use or socio-economic variable. Trip distribution is a determination of where the traffic is going to (destination) and leaving from (origin). Trip assignment is the accumulation of traffic on specific roadways which link the origin and destination of trips. As a final step to the model development process, the models are calibrated to simulate the traffic flows over a base year, for this project, it was 1991. Upon calibration of the models, future land use data was input to the models to project future travel demand and identify future circulation improvement requirements.
Using the daily traffic projections from the traffic demand model the year, 2010 roadway traffic conditions were evaluated. This future year analysis assumed, as previously discussed, the third bridge crossing over the Feather River. This assumed bridge crossing connected Bogue Road at Garden Highway and Feather River Boulevard/Erle Road in Yuba County. Tables 4.9-1 and 4.9-2 show the future roadway levels of service of the State Highways and County roadway segments, respectively. The operating conditions presented in Tables 4.9-1 and 4.9-2 identify conditions which would exist at 2015 general plan build out if no roadway improvements are made. Figure 4.9-1 graphically presents future Levels of Service on Sutter County roadways.

TABLE 4.9-1
FUTURE PROJECTED OPERATING CONDITIONS ON
STATE HIGHWAY SEGMENTS