Final Traffic Impact Report for the West Entry Parking Structure

September 9, 2002

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I. INTRODUCTION Purpose The purpose of this report is to present the results of the transportation analysis of the West Entry Parking Structure (WEPS). This study analyzed the traffic impacts associated with the proposed WEPS, located on the University of California, Davis campus. Potential impacts of the WEPS on the roadway, transit, bicycle, and pedestrian systems in the vicinity of the project site were analyzed under existing and cumulative conditions. Improvements to intersections and roadways in the vicinity of the project site were recommended to offset project impacts as necessary. This report is organized as follows:

• Chapter I – Introduction: summarizes the proposed WEPS, analysis methodology, and significance criteria used to identify project impacts;

• Chapter II – Existing Conditions: describes the transportation network in the

vicinity of the project site and the existing traffic volumes and peak hour operations;

• Chapter III – Existing Plus Project Conditions: presents the trip generation, distribution, and assignment of project trips onto the surrounding roadway network and summarizes the resulting traffic operations and project impacts with the construction of the proposed WEPS;

• Chapter IV – Cumulative Conditions: summarizes the projected traffic volumes

and operations for study intersections (Year 2005) and at the SR 113/Hutchison Drive interchange (Year 2025) with and without the proposed WEPS and identifies project impacts;

• Chapter V – Mitigation Measures and Recommended Improvements:

recommends improvements to study intersections to restore operations to an acceptable level, evaluates sight distance for vehicles turning from Dairy Road onto La Rue Road, suggests improvements along Hutchison Drive to accommodate the increase in traffic volumes with the WEPS, analyzes the operations of roundabouts on La Rue Road at Dairy Road and Bioletti Way, and discusses potential impacts to emergency vehicles with the construction of the WEPS;

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• Chapter VI – Project Access: evaluates the proposed access to the project site including the opportunities and constraints of providing access on Dairy Road and/or Bioletti Way and discusses access to/from the WEPS at the main driveway and secondary driveway;

• Chapter VII – Pedestrians and Bicyclists at Unsignalized Intersections: presents

the results of the VISSIM micro-simulation analysis and recommends improvements in consideration of bicyclists and pedestrians traveling through the Hutchison Drive/Dairy Road and Hutchison Drive/Kleiber Hall Drive intersections;

• Chapter VIII – Hutchison Drive Access: summarizes the effects of eliminating

access on Hutchison Drive east of Bioletti Way to determine if the reduction in traffic volumes on Hutchison Drive would reduce the needed improvements to serve the proposed WEPS; and

• Chapter IX – Roundabout Dimensions and Operations: suggests the dimensions

of a roundabout at the Hutchison Drive/Bioletti Way intersection and analyzes traffic operations with the construction of a roundabout.

Proposed Project The proposed WEPS will replace an existing surface parking lot, Lot 45, located on the north side of Hutchison Drive between Dairy Road and Kleiber Hall Drive (see Figure 1). The proposed WEPS will provide 1,500 parking spaces and will displace 290 spaces from the existing surface parking in Lot 45, resulting in a net increase of 1,210 parking spaces. The main driveway entrance/exit to the WEPS will be provided by extending Dairy Road north of Hutchison Drive and the secondary driveway will provide access onto Kleiber Hall Drive. Both driveways will include one inbound and one outbound travel lane. Hutchison Drive will serve as the primary access road to/from the north and west (i.e., vehicles traveling towards SR 113 and Russell Boulevard). Access to the south (i.e., towards Old Davis Road) will be provided under one of the following access scenarios:

1. Dairy Road only; 2. Bioletti Way only; or 3. Dairy Road and Bioletti Way.

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Based on discussions with UC Davis staff, Dairy Road is the preferred southern access route for vehicles traveling to/from the WEPS. However, this report includes a complete analysis of each of the three access scenarios1 and discusses the opportunities and constraints of each scenario. In addition to the 290 spaces located in Lot 45 that will be displaced with the construction of the WEPS, the following nearby surface lots will also be removed with the implementation of the WEPS:

• Lot 28 (90 spaces); • Bioletti Way on-street parking (51 spaces, Scenarios 2 and 3 only); and • Dairy Road on-street parking (68 spaces, Scenarios 1 and 3 only).

Analysis Methodology Level of service (LOS) is a qualitative measure describing the operating condition of intersections and roadways. LOS ranges from A through F, which represents driving conditions from best to worst, respectively. In general, LOS A represents free-flow conditions with no congestion, and LOS F represents severe congestion and delay under stop-and-go conditions. Signalized Intersection Analysis The signalized intersections were analyzed using the methodology presented in the Highway Capacity Manual (2000 HCM), Transportation Research Board, 2000. This methodology determines the LOS at signalized intersections by comparing the average control delay per vehicle at the intersection to the thresholds shown in Table 1. Unsignalized Intersection Analysis The unsignalized intersections were also analyzed using methods described in the 2000 HCM. This methodology reports the LOS using the delay thresholds shown in Table 2.

1 The ramp junction analysis was only conducted for access Scenario 1 (i.e., Dairy Road).

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Table 1

Level of Service Definitions – Signalized Intersections

Level of Service Average Control Delay (seconds per vehicle)

A < 10.0 B 10.1 – 20.0 C 20.1 – 35.0 D 35.1 – 55.0 E 55.1 – 80.0 F > 80.0

Source: Highway Capacity Manual, Transportation Research Board, 2000.

Table 2 Level of Service Definitions – Unsignalized Intersections

Level of Service Average Control Delay (seconds per vehicle)

A < 10.0 B 10.1 – 15.0 C 15.1 – 25.0 D 25.1 – 35.0 E 35.1 – 50.0 F > 50.0

Source: Highway Capacity Manual, Transportation Research Board, 2000.

As described in the 2000 HCM, the LOS for all-way stop controlled intersections is based on the average control delay for the entire intersection. Conversely, for side-street stop-controlled intersections, the LOS is measured separately for each individual movement. To be consistent with both 2000 HCM and recent UC Davis planning studies, this report documents the LOS for side-street stop-controlled intersections in two forms:

• Intersection LOS, based on the average control delay for the entire intersection; and • Worst-Case LOS, based on the average control delay experienced by the worst

movement of the intersection. The recommended mitigation measures for side-street stop controlled intersections were targeted to improve the worst-case LOS to an acceptable level.

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Ramp Junction Analysis The on-ramps and off-ramps at the SR 113/Hutchison Drive interchange were also analyzed using methods described in the 2000 HCM. This methodology reports the LOS using the density thresholds shown in Table 3.

Table 3 Ramp Junction Level of Service Criteria

LOS Maximum

Density (pc/mi/ln) Description

A < 10 Unrestricted operation. Merging and diverging vehicles have little effect on other freeway flows.

B > 10 - 20 Merging and diverging maneuvers become noticeable to through drivers, and minimal levels of turbulence exist.

C > 20 - 28 Average speed within the ramp influence area begins to decline as the level of merging or diverging turbulence becomes noticeable.

D > 28 - 35 Turbulence levels become intrusive, and virtually all vehicles slow to accommodate merging or diverging maneuvers.

E >35 Represents condition approaching and reaching capacity operation. Speeds reduce to the low 40s (mph), and the turbulence of merging and diverging maneuvers becomes intrusive to all drivers in the influence area.

F * Represents saturated conditions. At this level, approach demand flow exceeds the discharge capacity of the downstream freeway (and ramp, in the case of diverge areas).

Notes: * Demand exceeds capacity. Source: Highway Capacity Manual, Transportation Research Board, 2000.

Significance Criteria In identifying operational deficiencies based on the LOS analysis, the following LOS thresholds, identified in the UC Davis 1994-2005 Long Range Development Plan Environmental Impact Report (EIP Associates, 1994), were used:

• LOS D is the minimum acceptable LOS for intersections within the Central Campus (i.e., study intersections bounded by Health Sciences Drive to the west, Mrak Hall Drive to the east, Old Davis Road to the south, and Orchard Park Circle to the north);

• LOS E is the minimum acceptable LOS for intersections within the City of Davis; • LOS C is the minimum acceptable LOS for intersections within Yolo County (i.e.,

study intersections outside of the City of Davis and Central Campus); and

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• LOS D is the minimum acceptable LOS for SR 113 and its associated interchanges based on Caltrans standards.

For side-street stop controlled intersections, the minimum acceptable LOS was based on the overall delay at the intersection. Although the intersection was said to operate acceptably if the overall delay met the minimum LOS standards, mitigation measures were recommended to improve the worst-case LOS to an acceptable level. Based on these LOS thresholds, a minimum LOS of “D” was used for each study intersection and ramp junction except for the Russell Boulevard/La Rue Road intersection in the City of Davis, which has a minimum LOS of “E”. Peak Hour Factor According to the 2000 HCM, the peak hour factor defines the relationship between the hourly traffic volumes and the peak 15-minute flow rate. The peak hour factor is an indicator of how much of the peak hour traffic occurs during the peak 15-minute period. Factors range from 0.25 to 1.00, with 1.00 representing an equal distribution of peak hour trips over the entire hour and 0.25 representing the clustering of the entire hour’s trips into a single 15-minute period. For the existing conditions analyses, peak hour factors were calculated at each of the study intersections using the existing 15-minute traffic volumes at each intersection. These peak hour factors ranged from 0.69 to 0.84. For the cumulative analysis, a peak hour factor of 0.75 was used for all study intersections. While this peak hour factor is lower than typical peak hour factors for urban areas, it reflects the focusing of vehicle trips that result from a rigid University class schedule. A peak hour factor of 0.90 was used for the freeway ramp junction analysis.