HomeMy WebLinkAbout2/18/2025 Item 7b, Horn and Banker-Hix - Staff Agenda CorrespondenceCity of San Luis Obispo, Council Memorandum
City of San Luis Obispo
Council Agenda Correspondence
DATE: February 18, 2025
TO: Mayor and Council
FROM: Matt Horn, Public Works Director
Prepared by: Wyatt Banker Hix, Supervising Civil Engineer
VIA: Whitney McDonald, City Manager
SUBJECT: ITEM 7B. – PRADO INTERCHANGE PROJECT UPDATE AND AWARD
PLANS, SPECIFICATIONS AND ESTIMATES (PS&E) DESIGN
CONTRACT
Staff received the following questions regarding Item 7b:
1) Page 563 of the Council Agenda Report of 9/5/23 shows Table 5.1 –
Alternative A3 Design Year (2050) Peak Hour Mainline, Ramps and Weaving
Section Operation. This table shows that most analyzed segments fall below
LOS C with the A3 project. Am I interpreting this correctly? What is Caltrans
position on A3 given this? I could not find any comparison to the "No Build"
alternative. Were comparable LOS estimates made?
Yes, analysis of traffic conditions both on and off the US 101 mainline were
evaluated for a No-Build scenario and for each interchange design alternative
considered, including the final preferred alternative design for a tight diamond
interchange (A3). While some design alternatives provided benefits of additional
on/off-ramp length for deceleration/acceleration on and off the US 101 mainline,
the traffic operations results on the US 101 mainline and ramp
merge/diverge/weave were generally similar for all the alternatives. There are
segments of US 101 in the vicinity that will fall below Caltrans’ level of service
(LOS) targets with or without the Prado Interchange Project. Ultimately, the
addition of the northbound auxiliary lane along US 101 between Prado Road and
Madonna Road, which was assumed in all interchange design alternatives,
improves the merge/diverge/weave operations in the northbound direction
compared to a No-Build scenario. The final preferred alternative supported by
Caltrans and previously adopted by the City Council on 9/5/23 were determined
based on a variety of metrics and considerations, including traffic operations on
and off the US 101, safety/collision potential, cost, right-of-way and environmental
impacts. Alternative A3 ultimately represented the design option that best
balanced these priorities.
7b. Prado Interchange Project Update and Award PS&E Page 2
2) According to the staff report there is $5.2M for the PS&E allocated from the
Local Revenue Measure fund. Is this already allocated from the current or a
previous budget? Or would this be allocated in the 25-27 financial plan?
These funds have already been allocated to the project from current and previous
budgets. No additional funding requests from the Local Revenue Measure will be
requested as part of the 2025-27 Financial Plan.
3) The section discussing construction debt financing shows $6M to $12M in
potential commitments for debt payments. Where would this funding come
from? Once the City debt financed would it still be possible to obtain state
or federal funding to cover the payments or pay off the balance?
This funding would be allocated from the City’s Capital Improvement Plan (CIP)
budget. Once the City issues debt, the payments would come from the CIP budget.
It is highly unlikely State or Federal grants could be used to cover those debt
payments.
That being said, staff does intend to seek State and Federal grants to help reduce
the impact of the project on the City finances.
4) Is there a report from the Central Coast Transportation Consulting (CCTC)
sensitivity analysis or just what is in the agenda report?
The updated traffic modeling forecasts were completed just in time to present
updated findings to the Council for this agenda item, but the data has not yet been
compiled into a formal report. Based on direction from the Council during this
hearing, including interest in modeling additional analysis scenarios (i.e. results
with increased non-auto mode share), staff will have a formal summary report
prepared, which will be shared with the Council and can be published on the project
website.
5) Why don't we model traffic impacts considering the City adopted mode share
goals? Why only consider the worst case analysis? My understanding is that
CEQA does not require worst case analysis.
While the City’s Travel Demand Forecasting Model does have components that
capture expected increases in non-auto mode share with improvements to transit
service, pedestrian and bicycle infrastructure, and increases in infill and mixed-use
development within the city, the model is generally calibrated to existing traffic
patterns which reflect existing mode share distribution. The reason that the model
is not calibrated to reflect the City’s adopted future mode share targets is that the
model is predominantly used for the purposes of forecasting traffic volumes and
VMT for development review and California Environmental Quality Act (CEQA)
analysis, and the City needs to be able to defend the model analysis and related
findings as reasonable, if not slightly conservative, to defend development
7b. Prado Interchange Project Update and Award PS&E Page 3
approvals from legal challenge. This intent is not to represent a worse-case
scenario, but analysis that is reasonable and defensible.
The mode share goals adopted in the General Plan Circulation Element are
inherently ambitious and while the City is aggressively implementing projects and
programs to support these goals, there is a reasonable likelihood that these goals
are not achieved within the current planning horizon. The table below compares
the City’s mode share goals against current mode share per a 2024 Household
Travel Survey.
Staff is happy to have additional traffic analysis scenarios prepared for the Prado
Interchange Project to test the sensitivity of the current modeling results to further
increases in non-auto mode share. However, it should be noted that the majority
(apx. 55%) of citywide auto trips have at least one trip end outside of the city limits,
and it is unlikely that the city can achieve the targeted mode share goals for
regional trips that are traveling to/from the city from elsewhere in the region. Even
when assuming higher non-auto mode share percentages in the traffic modeling
for local trips, the ultimate reduction in citywide auto trips may improve projected
traffic operations slightly but is unlikely to completely resolve the projected traffic
operations impacts identified in current projections.
6) Why did the City pursue CEQA IS-MND’s instead of a single EIR for the Prado
Interchange, Bridge and Extension projects?
Each of the three Prado projects are being developed along a different timeline,
with the Prado Bridge anticipating construction in 2027, the Prado Interchange in
2029, and no timeline for the Prado Extension. The Prado Extension lacks any
concept level plans or anticipated impacts, and this will not be known until the
property develops, making an environmental analysis not possible at this time.
Before embarking on either the Prado Bridge or Interchange projects, City and
Caltrans staff met to discuss each project and their environmental impact. Since
each project has different funding mechanisms, timelines and project needs, City
and Caltrans staff determined each project should proceed under separate
environmental documents, with each pursuing CEQA IS-MND’s. However, all
projects have been subject to comprehensive environmental review as part of the
Land Use and Circulation Element Update and relevant area and/or specific plans,
as well as detailed analyses included as part of major development plan EIRs.