Non-CEQA Transportation Assessment
Level of Service (LOS) Analysis Procedure
Traffic analysis must be conducted under the supervision or by a registered traffic engineer, civil engineer, or qualified transportation planner. Before initiating the analysis, the analyst and project applicant must meet with Planning Department and Public Works staff to agree on the study area, assumptions, and methodologies. All assumptions and methodologies for the LOS analysis must be reviewed and approved by the City Traffic Engineer.
An LOS analysis is required for projects that meet any of the following criteria:
- Projects that propose variations from the standards and guidelines in this manual.
- Projects expected to generate more than 50 net new vehicle trips during the AM or PM peak hour.
- Projects where the combination of land use and location warrant analysis at the City’s discretion, even if the trip threshold is not met.
The Director of Public Works may also require an analysis if current or proposed traffic conditions in the project area justify it.
Traffic Counts
Traffic counts older than two years should not be used unless approved by the City Traffic Engineer. If no recent traffic counts are available, a qualified data collection firm must gather new data. Turning movement counts at study intersections should be taken in 15-minute intervals from 7:00 AM to 9:00 AM and 4:00 PM to 6:00 PM, unless otherwise specified. Generally, counts should be conducted when local schools are in session, on days with good weather, from Tuesday to Thursday during non-summer months, and should avoid holiday weeks.
Trip Generation
The City accepts trip generation rates from the latest edition of the ITE Trip Generation Manual. If a project’s land use is not covered in the ITE manual, trip generation rates from other agencies or locally approved studies may be used, with supporting documentation required. The analysis should justify any trip generation credits, such as existing uses, transit, or internal capture. Pass-by traffic credits must be based on ITE data or city-approved studies.
Trip Distribution and Assignment
The analysis must include a description of how project-generated traffic will be distributed and assigned to specific roadways. The methodology and assumptions for trip distribution must be approved by the City Traffic Engineer and should consider demographic or market data and the project’s location relative to regional roadways.
Trip assignments should be based on existing and projected travel patterns, considering the future roadway network and travel time characteristics. Trip assignments should reflect project trip generation minus applicable credits.
Traffic Forecasts
The analysis must include total traffic expected at the buildout of the project, factoring in cumulative effects of other projects. The future year forecasts should use the latest SCAG Travel Demand Model or appropriate sub-area travel demand model, and the methodology must be approved by the Director of Public Works.
Until the City’s General Plan update is completed, future buildout forecasts should follow growth rates from the prior LA County Congestion Management Program or the SCAG model.
Analysis Methodologies
The City uses the latest version of the HCM (Highway Capacity Manual) methodology to assess LOS at intersections, based on vehicular delay. LOS ranges from A (free flow) to F (heavy congestion). The peak hour is identified as the highest one-hour period from four consecutive 15-minute intervals in both AM and PM counts.
Key parameters for LOS determination include:
- A peak hour factor (PHF) based on observed conditions for existing traffic and a PHF of 0.95 for future conditions.
- Signalized intersection parameters include a cycle length and pedestrian timing, with minimum left turn split time at 10 seconds.
- Saturation flow rates for various lane types, adjusted for pedestrian and heavy truck activity when needed.
Acceptable analysis programs include Synchro, Vistro, or HCS. Any other program requires approval from the Director of Public Works.
Analysis Scenarios
LOS analysis should evaluate the following scenarios, as required by the Director of Public Works:
- Existing Conditions: Traffic data from within the previous two years.
- Opening Year: Existing traffic plus ambient growth and traffic from pending or approved developments. Multiple opening years may be needed for phased projects.
- Opening Year plus Project: Existing traffic, ambient growth, and approved developments, plus project traffic.
- Horizon Year: Buildout of the City General Plan and circulation system, using SCAG or other projections. Required for projects contributing to intersections with unacceptable LOS or requiring General Plan amendments.
- Horizon Year plus Project: Cumulative traffic for Horizon Year plus project traffic.
For phased developments, interim year analyses are required to assess traffic impacts at each phase. Analysis years must align with project phasing and be approved by the City Engineer.
A summary table showing forecast LOS for each intersection in all scenarios, including improvements, must be included in the report.
Transportation Effects
The City’s acceptable LOS is D or better. Intersections operating at LOS E or F are considered deficient. Improvements will be required if:
- Project traffic degrades intersection operations from LOS D or better to LOS E or F.
- For intersections already at LOS E or F, the project must contribute to improvements to bring the LOS to acceptable levels, or provide a fair share toward improvements. This may include upgrading traffic signal equipment or software.
For unsignalized intersections, improvements are required if:
- Project traffic degrades the intersection to LOS E or F, and
- The intersection meets peak hour signal warrants, based on project volumes or existing conditions.
On-Site Parking Analysis
The analysis must compare the project’s on-site parking supply with City code requirements. For mixed-use developments, a table should detail each land use, size, code parking requirements, and the resultant surplus or deficit. Justification for any parking reductions should be provided, but this does not eliminate the need for a zoning code variance.
Access and Circulation Analysis
This analysis must address the following:
- Number and location of access points.
- Spacing between driveways and intersections.
- Potential signalization of driveways.
- On-site stacking distances, particularly for drive-thrus.
- Shared access arrangements.
- Turn conflicts or restrictions, including truck turning templates where necessary.
- Adequate sight distance for ingress and egress.
- Pedestrian connectivity.
- Any other operational characteristics identified by City staff.
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