Prepared by the Ventura Citizens for Hillside Preservation
Technical Committee

Executive Summary. This analysis examines the vehicular trip generation effects of proposed Measure A (also known as the proposed Open 80 Master Plan Act) on the City of Ventura street network and, particularly, operational effects to Foothill Road. This analysis uses industry standard calculation methods to examine how many new vehicular trips would result from the development of the 1,390 houses, 40,000 square feet of commercial development, and 32 acres of neighborhood parkland in Measure A. In addition to the analysis of trip generation, it also calculates project-caused Level of Service (LOS) changes that would occur along four segments of Foothill Road. This report does not include analysis of impacts to the citywide roadway network that would be expected to occur, since detailed traffic modeling and precise assumptions about future roadway system design in the area affected by Measure A development would be required. Trip data were taken from two sources: the Institute of Transportation Engineers' Trip Generation 6th Edition, and the City of Ventura Comprehensive Plan Comprehensive Plan Update Background Report.

At full build-out, Measure A would generate approximately 14,680 Average Daily Trips from six new hillside neighborhoods. With no new planned arterial streets, these trips would all be required to use the Poli Street/Foothill Road facility for east-west travel and for access to north-south connector streets into the City street network. Level of Service would degrade from "A" and "B" to "E" and "F" on the four segments analyzed.

Measure A Trip Generation. Based on current accepted trip generation studies as compiled by the Institute of Transportation Engineers (ITE), vehicular trips can be estimated depending on the type of land uses proposed. These estimates are used by most public agency engineering departments to project traffic from proposed developments and understand impacts and resulting required modifications to urban street networks in development-affected areas. The data are categorized by daily occurrence, and are referred to as average daily trips (ADT).

There are four land use categories proposed in Measure A that will generate vehicular trips. These are: single-family residential; townhouse residential; neighborhood-serving commercial; and, neighborhood park. Table 1 illustrates the proposed land uses, the amount of development per category, the trip factor per unit, and the resulting trips generated by each land use.

Of the land use development types proposed in Measure A, single-family residential uses will generate the largest number of new trips. Analysis of the Open 80 Master Plan indicates that of the 1,390 dwelling units proposed, 1,285 will be single-family dwelling units. The ITE estimates that for each new single-family dwelling unit developed, an average of 57 trips will be generated. This results in 12,297 new ADT for the single-family development portion of the proposed Measure A development.

The Open 80 Master Plan indicates that in three of the neighborhoods (Hall Canyon, Poinsettia Terrace and Sexton Canyon) attached or zero lot line units (i.e., townhouses) may be constructed. Since these types of units typically generate fewer daily trips than single-family detached homes, this analysis takes a conservative approach and includes a portion of townhouse units in the traffic analysis. (Using only single family detached units to estimate the number of daily trips generated by the proposal would yield higher trip estimates.)

Based on analysis of the illustrative master plan renderings in Exhibit D of Measure A, it is projected that 105 townhouse-style dwelling units would be built (7.5% of the 1,390 dwelling units in the Measure). This category of land use generates an average of 5.86 trips per unit, according to the ITE. Therefore, 616 average daily trips would be generated from this type of hillside development proposed in the Open 80 Master Plan.

A total of 40,000 square feet of commercial development would be developed at two "town centers." Since detailed retail or office use types have not been identified in Measure A, this analysis uses the broader factor category of "shopping centers." The ITE generation rate for shopping centers is 42.92 average daily trips per 1000 square feet of development. The anticipated average daily trip totals for the commercial component of the Measure A development would therefore be 1,717.

Finally, Measure A calls for 32 acres of parkland, in two locations. The ITE trip generation rate for this land use category is 1.59 average daily trips per acre. Therefore, there would be a total of 51 average daily trips generated from the neighborhood park uses. After combining the number of trips generated in each land use category, a total of 14,680 trips would be generated by the Measure A development.

Existing Operational Conditions of Foothill Road. The City of Ventura keeps updated information on the number of ADT that occur on arterial and other important streets in the City. These data were recently presented in the City's Comprehensive Plan Background Report (August 2002). Street segments are designed to handle a particular amount of ADT. Physical factors that are influence a street's ability to accommodate ADT include number of travel lanes per direction of traffic, number of intervening intersections, number of traffic signals, and overall road width. Using this combination of factors, roadway segments are rated for their carrying capacity. By dividing the roadway capacity by the number of ADT, engineers determine a statistic called the volume-to-capacity ratio, or V/C ratio.

From this V/C statistic, a street segment's operational function can be determined. The system most widely used to describe this function is the Level of Service calculation, or LOS. LOS ratings vary from level of service of "A" (roadways operate with free flow conditions) to level of service o "F" (severe congestion).

Table 2 provides a summary of existing operational data for four segments of Foothill Road between Seaward Avenue and Victoria Avenue.

The data illustrate that at present Foothill Road generally operates with free-flow conditions.

Impacts of Measure A on Foothill Road. As described above, a total of 14,640 additional trips per day would be expected to be generated from the development proposed in Measure A. Using a generalized distribution of trips from the developed areas based on current traffic origin and destination data available for Ventura, it is estimated that 40% of the Measure A trips would use Foothill Road in a westerly direction, 40% would use Foothill Road to access southbound routes, and 20% would travel easterly. To calculate impacts to Foothill Road street segments, this distribution pattern was used to calculate the additional traffic from Measure A development that would travel on each of the Foothill Road segments. The resulting impacts are shown in Table 3.

Measure A development would add trips to the segments of Foothill Road in varying amounts in accordance with projected future trip distribution patterns. The Seaward to Hillmont Avenuesegment would be expected to experience an addition of 10,000 ADT. The Hillmont Avenue to Hamilton Street/Ashwood Avenue segment would be expected to experience an addition of 6,000 ADT. The segment from Hamilton /Ashwood Avenue to Day Road would be expected to experience an addition of 9,000 ADT, and the segment from Day Road to Victoria Avenue would be expected to experience an increase of 5,000 ADT. The capacity of Foothill Road from Seaward Avenue to Day Road would be exceeded, and for each of the three segments in that span of roadway, level of service would degrade to LOS "F." For the segment from Day Road to Victoria Avenue, level of service would decline to LOS "E."

Mitigation of Impacts. Typically, level of service impacts identified through detailed traffic reports require mitigation. Usually, this mitigation is accomplished through provision of (1) new alternative arterial roads that can carry the increased traffic burden, or (2) expansion in capacity of the system through the addition of traffic lanes and through a variety of traffic control devices (traffic signals and signage). In the case of the Measure A development proposal, no new arterial roads have been identified. Therefore, it is expected that mitigation would be required to increase capacity along Foothill Road and Poli Street through the length of the impact zone. Typically, the City has required that additional travel lanes be constructed to provide additional capacity. Such an approach would have serious consequences to existing residential neighborhoods that line most of Foothill Road and all of Poli Street. For undeveloped segments along the north side of the road, extensive grading and slope stabilization would be required to add the necessary additional width. Preliminary analysis indicates that as many seven new traffic signals would be required along Foothill Road and surrounding streets.

Conclusion. The Measure A development would generate an additional 14,680 average daily trips to Ventura's street system. Since no new arterial roadways are planned to accommodate these trips, Foothill Road would be the primary arterial street receiving the increased traffic load. The effect would be serious congestion of Foothill Road, resulting in a degradation of Level of Service from "A" (free flow conditions) experienced today to "F" (seriously congested) to two of the four roadway segments, and a degradation from LOS "A" to "E" and LOS "B" to "E" on the other two segments. A more detailed analysis is warranted to ascertain precise impacts to neighborhood streets and the citywide roadway network.

Because the trips would not stop at Foothill Road, but would use the arterial to feed into the overall street system, a more detailed traffic analysis is warranted to determine which additional roadways and intersections of the City's street system would be impacted and what mitigation measures are necessary to ameliorate those impacts.

Sources
Institute of Transportation Engineers, Trip Generation, 6th Edition, 1997
City of Ventura, Comprehensive Plan Update Background Report, August 2002
Lloyd Properties LLC Open 80 Master Plan Act, 2002

© 2002 Ventura Citizens for Hillside Preservation VCHP, No on Measure A Committee

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