TURNSTONE PARKING MANAGER
DETAILED SOW February 2026
This document outlines the core processes & deliverables Turnstone will provide to Santa Rosa to best support the paid parking program annually. This document is divided into four sections:
Principles of Operation, Platform Functionality, Additional Services, and Project Budget.
OPERATING PRINCIPLES
Applying relevant lessons from work we're doing with other cities, we follow core operational principles, including:
1. Communication. Turnstone facilitates regular Project Meetings with the City to ensure the platform continues to meet Santa Rosa's needs and to provide a forum for discussion, adaptation to, and adjustment of Santa Rosa's parking program.
2. Accountability. Detailed notes are kept for all meetings, tracking discussions, actions, and follow-through. These notes are shared with all identified stakeholders to ensure alignment and that action items are not missed.
3. Information Sharing. The Turnstone team works with cities of all sizes across the country and has developed specialized expertise in parking. Turnstone will freely share that expertise & information with Santa Rosa, with permission where required.
4. Support. Turnstone can also provide ad hoc support for program development and management. This can include data acquisition & analysis, custom reporting, and the development and execution of advanced predictive models.
By following these principles, we will ensure the City of Santa Rosa receives maximum benefit with minimal commitment, leveraging a system that's consistent, reliable, and easy to use.
PLATFORM FUNCTIONALITY
The Turnstone Parking Manager dashboard will provide continuous, cloud-based data analysis and visualization around curbside parking occupancy, and automatic insights into what’s happening across the City at all times. Users will be able to access clear data visualizations to support the implementation and management of policies, including time limits, rate changes, and on-demand investigation. All data on the platform will be available for download to support offline analysis and/or presentation in other formats. These user benefits are made possible by a unique set of features not available on any other platform. 1 Attachment 1
Data Aggregation & Normalization
Turnstone normalizes multiple complex data types from any vendor, supporting operational analyses.
Data
types
can
include
(but
are
not
limited
to)
hardware
and
mobile-based
transactions,
dynamic
on-street
supply,
lot
and
garage
inventory,
reservations,
permits,
and
events.
All
of
these
types
are
'normalized'
such
that
they
can
be
compared,
combined,
and
otherwise
used
in
concert.
Data Monitoring & Alerting Services
Transactions come from multiple vendors in every city, all with their own mapping, format, and standards.
Turnstone
monitors
these
inputs
continually
for
gaps,
dramatic
changes,
and
trends
over
time,
and
triggers
alerts
when
action
is
required.
Zone/Neighborhood Mapping
Turnstone aggregates supply from the block level up to the neighborhood level. If block-level supply
is
known,
the
zone's
supply
is
the
sum
of
all
blocks
in
the
zone.
This
means
that
occupancies
are
always
at
the
lowest
and
highest
levels
of
inspection,
from
block
all
the
way
up
to
citywide.
If
supply
changes
at
any
time,
the
entire
city
can
be
updated
easily
(and
automatically)
with
no
manual
data
entry
required
by
the
City.
Data Modeling
Turnstone employs several layers of models in order to effectively create a digital representation of
the
City's
curb.
This
collection
of
models
enables
Turnstone
to
make
intelligent
predictions
about
non-payment
while
also
providing
the
underlying
data.
The
availability
of
each
model
2 depends on the data sources available.
1. Dynamic Supply Tracking. The inherently dynamic nature of parking space availability in a
city
is
a
key
driver
for
Turnstone’s
continuous
collection
and
aggregation
of
accessible
data
on
parking
supply,
ensuring
a
clear
and
accurate
view
of
the
parking
system.
Requires:
a
source
of
permit
and/or
red
bag
data.
2. Paid Parking Demand. Turnstone combines transaction data from all hardware meters and
mobile
payment
applications
to
determine
the
average
number
of
spaces
per
hour
paid
on
a
given
block
face.
Requires:
transactional
data.
3. Duration of Stay. Although Paid Parking Demand indicates the general usage of a block face,
it
doesn't
account
for
under-
or
overpayment.
Turnstone's
next
layer
of
analysis
is
a
statistical
curve,
trained
on
manually
collected
sample
data,
that
predicts
the
probability
that
a
paid
vehicle
remains
present
at
time
t
after
payment.
Requires:
transactional
data.
4. Unpaid Behavior. Even with accurately calculated paid behavior, the actual usage of a block
face
may
vary
due
to
unpaid
parking
events.
Turnstone's
advanced
model
is
trained
to
predict
unpaid
behavior
relative
to
paid;
this
prediction
is
then
layered
on
top
of
duration-of-stay
to
better
understand
what
is
happening
in
the
real-world
system.
Requires:
training
data.
5. Overnight Vehicles. Many cities allow vehicles to park for free outside paid hours, both after
the
end
of
the
day
and
in
the
morning
before
the
start
of
the
day.
Turnstone's
overnight
model
accounts
for
these
vehicles,
again
using
historical
samples
for
training
to
generate
occupancy
predictions
for
any
given
block
face
or
zone
in
a
city
with
high
accuracy.
Requires:
training
data
&
accurate
supply
count.
6. Drift Analysis. On a regular—and automated—basis, Turnstone monitors predefined indicators
that
indicate
a
change
on
a
given
block
face.
If
a
significant
change
is
detected,
further
analysis
or
updated
sampling
is
recommended.
Requires:
transactional
data.
Business Intelligence
The backend features described above work in concert to ensure data is complete, accurate, continuous,
reliable,
and
detailed
enough
to
support
the
front-end
functionality
that
delivers
real
value
to
Turnstone's
users.
3 ● Interactive Parking Map reflects transaction volumes, parking demand, rates, and dynamic
supply
at
citywide,
zone,
and
block
face
levels.
Provides
users
with
a
direct
visual
comparison
between
paid
demand
and
actual
on-street
demand,
accounting
for
ADA,
RPZ,
and
other
non-payment
behaviors.
● At-a-Glance Metrics on Average Occupancy, Hourly Occupancy, and Rate vs. Occupancy by
day,
hour,
or
peak
period.
● Parking Impact Analysis Report that will help the City evaluate how changes to land use, parking
supply,
and
permit
allocation
affect
program
performance,
particularly
occupancy
and
revenue.
● Full Data Exports can be downloaded at any time for the dates selected in Parking Manager,
reflecting
all
available
values
at
the
blockface
level.
Includes
hourly
capacity,
reservations,
available
spaces,
paid
&
modeled
occupancy,
parking
rate,
and
net
accrued
dollars.
Download
up
to
three
months
at
once.
Data Collection
To support the City's accuracy goals, two data-collection efforts will be conducted annually, providing
citywide
on-
and
off-street
occupancy
observations
to
validate
parking
behavior
and
continuously
train
the
data
models
Turnstone
employs
to
predict
nonpayment.
4 OPTIONAL SERVICES
The following services can be provided upon request, subject to a fixed-fee quote and written approval
from
the
City.
Rate Review Support
Additional tools & assistance for rate adjustment programming are available on request. This includes
analysis
of
current
and
future
paid
occupancy,
incorporating
seasonal
trends.
Analysis
is
shared
for
the
city's
review
and
further
assessment,
and
Turnstone
provides
subject-matter
expertise
throughout
the
process.
Can
be
provided
at
any
time
with
4 weeks'
notice.
Ad Hoc Data Analysis
Turnstone is staffed with data scientists and engineers who can run trend analyses, what-if? scenarios,
budget
projections,
or
other
ad
hoc
requests.
These
can
be
requested
at
any
time
through
project
meetings
or
via
email.
Custom Reporting
Turnstone includes functionality for automated report generation and distribution. Reports that include
information
already
available
in
the
platform's
backend
can
be
developed
on
request.
This
process
would
include
discovery
calls
with
stakeholders,
design
&
planning
to
ensure
the
report
meets
stakeholder
needs,
and
implementation.
Turnstone Community
Paid parking programs across the country face similar challenges, and cities have developed varied
approaches
to
address
them.
Turnstone
is
committed
to
facilitating
knowledge
sharing
to
advance
program
development
nationwide.
As
the
Turnstone
community
grows,
the
City
will
have
an
opportunity
to
participate
by
sharing
ideas
and
learning
from
others.
For
members
that
opt-in,
Turnstone
will:
● Share relevant learning between municipalities, when permitted; ● Offer to connect organizations facing similar challenges; and ● Facilitate collaborative sessions, virtual or in-person, when feasible.
5 PLATFORM FEES
Below is a summary of remaining costs for Year 1, along with costs for Year 2 and 3, which include
4,000–5,000
spaces,
monthly
project
management
meetings,
and
ad
hoc
data
analysis
support.
ITEM COST
Citywide Data Collection Completed 12/04/25
$ 4,485
Turnstone Platform Access Year 2 07/01/26 – 08/31/27 $ 55,000
Turnstone Platform Access Year 3 07/01/27 – 08/31/28 $ 60,500
Turnstone Impact Analysis Report 07/01/26 – 08/31/28 $ 24,000
Bi-Annual Data Collection (twice per year) 01/01/26 – 08/31/28 $20,000
Total (3 Years) $ 163,985
6 Registered Office: Attention: Scott Lee, 46505 SE Mt Si Rd, North Bend, WA, 98045, United States.
DRAFT INVOICE
City of Santa Rosa
100 Santa Rosa Ave
SANTA ROSA CA 95404
USA
Invoice Date
Feb 6, 2026
Invoice Number
INV-0209
Reference
2026-2028
Turnstone Data Inc.
Attention: Scott Lee
46505 SE Mt Si Rd
NORTH BEND WA 98045
UNITED STATES
Description Quantity Unit Price Tax Amount USD
Citywide Data Collection
(Completed 12/04/25)
1.00 4,485.00 Tax on
Sales
4,485.00
Turnstone Platform Access Year 2
(07/01/26 – 08/31/27)
1.00 55,000.00 Tax on
Sales
55,000.00
Turnstone Platform Access Year 3
(07/01/27 – 08/31/28)
1.00 60,500.00 Tax on
Sales
60,500.00
Turnstone Impact Analysis Report
(07/01/26 – 08/31/28)
1.00 24,000.00 Tax on
Sales
24,000.00
Bi-Annual Data Collection
(01/01/26 – 08/31/28)
1.00 20,000.00 Tax on
Sales
20,000.00
Subtotal 163,985.00
TOTAL TAX 0.00
TOTAL USD 163,985.00
Due Date: