City of Palo Alto
Grade Separation Project
Churchill Avenue, Meadow Drive,
and Charleston Road
City Council Meeting
December 15, 2025
Funded by:
Integrated
Project Team
Ripon Bhatia
Senior Engineer
Ria Hutabarat Lo
Chief Transportation Official
Jill Gibson
Edgar Torres
Whitney DiGiantommaso
Navi Dhaliwal
Provide additional information requested by City Council December 10 Special Meeting
Action: Determine which alternatives to advance to 15%
Meeting Purpose
3 4-Step Model
4 1. Trip Generation
(pop & jobs by zone)
2. Trip Distribution
(gravity model)
3. Mode Split
(by trip type, income etc.)
4. Route Assignment
(based on travel times)
• Best case: Transportation models are forecasts
- Models identify likely delay & simulate outcomes under assumed & forecasted conditions - All inputs are estimates, outputs are never 100% precise - Models are not deterministic; do not reflect macro changes, behavior change, random perturbation - Most accurate for expansion of business as usual
• Critical perspective: Model assumptions have known flaws - Water paradigm (flows, capacity, gravity)
- Do not account for policy & human choice
- Do not account for many elements of induced travel demand - Predict & provide; may be a self-fulfilling prophecy
- Typical prescription is capacity expansion
Understanding Accuracy of Models
5 Induced Travel Demand & Induced Investment
6 S1
Travel
time
(cost)
Q, Traffic Flow
(veh/hour)
Q1
T1
D1
Q2
T2
S2
T1b
D3
Q3
T3
• Density (higher land use density esp. around transit) • Diversity (mix of land uses, more housing in a job-rich city) • Design (walkable urban design)
• Destinations (high quality transit serving regional destinations) • Demand management (info, paid parking, transit passes etc.) What Other Choices Shape Demand?
7 1. Overall Network Delay
• Total time cars are stopped while
traveling through network
2. Approach Delay and
Movement Queues
• Delay: Average time cars stopped at
intersection per approach (e.g.,
northbound)
• Queue: Average distance cars stopped
at an intersection per movement
Traffic Analysis Information
8 Traffic Network for
Meadow/Charleston
3. Travel Times
• Vehicles: Calculated time that considers distance of travel path and average delay at signalized intersections along path
• Bicycles: Calculated time that considers distance of path, average delay at signalized intersections, and average travel speed per mode
Traffic Analysis Information
9 Year 2025 2040
Configuration Existing Hybrid Underpass
with RAB3
Underpass
with DAR3 Existing Hybrid Underpass
with RAB3
Underpass
with DAR3
AM
Per Vehicle1 1.5 min 1 min 0.5 min 0.5 min 3 min 1.5 min 0.5 min 0.5 min Total2 115 hrs 75 hrs 30 hrs 30 hrs 230 hrs 110 hrs 45 hrs 45 hrs PM
Per Vehicle1 3 min 1 min 0.5 min 0.5 min 6 min 2.5 min 0.5 min 0.5 min Total2 230 hrs 95 hrs 30 hrs 35 hrs 470 hrs 200 hrs 45 hrs 45 hrs
1. Rounded to nearest half minute
2. Rounded to nearest 5 hours
3. Assumes Meadow Drive is the underpass alternative
RAB = Roundabout | DAR = Direct Access Ramp
1. Overall Network Delay – Meadow & Charleston
10 2. Approach Delays (Seconds) – Meadow
11 Alma Street at Meadow Drive
Year 2025 2040
Configuration Existing Hybrid Underpass
with RAB1
Underpass
with DAR1 Existing Hybrid Underpass
with RAB1
Underpass
with DAR1
AM
Intersection 41.7 D 34.6 C 9.9 A 10.5 B 50.3 D 40.4 D 11.0 B 12.9 B Northbound 48.4 D 30.6 C *** *** 65.1 E 32.5 C *** ***
Southbound 32.8 C 29.4 C 10.4 B 11.7 B 35.1 D 37.5 D 13.0 B 14.1 B Eastbound 20.4 C 47.0 D 11.3 B 11.2 B 20.6 C 60.7 E 13.4 B 14.5 B Westbound 62.9 E 47.1 D 6.6 A 7.0 A 66.1 E 50.6 D 7.3 A 7.6 A PM
Intersection 62.6 E 37.9 D 9.8 A 10.2 B 81.4 F 49.8 D 12.9 B 12.5 B Northbound 33.5 C 38.4 D *** *** 36.5 D 29.4 C *** ***
Southbound 91.2 F 33.4 C 11.1 B 11.2 B 135.6 F 58.4 E 13.2 B 14.3 B Eastbound 22.8 C 45.7 D 9.7 A 10.9 B 23.3 C 65.0 E 15.4 B 13.2 B Westbound 73.4 E 45.4 D 7.1 A 7.2 A 97.3 F 55.4 E 8.6 A 7.5 A
1. Meadow Drive is the Underpass Alternative - Lower Intersection *** Movements not allowed at intersection approach
RAB = Roundabout | DAR = Direct Access Ramp
2. Average Queues (Feet) – Meadow
12 Alma Street at Meadow Drive
Year 2025 2040
Configuration
Existing Hybrid Underpass
with RAB1
Underpass
with DAR1 Existing Hybrid Underpass
with RAB1
Underpass
with DAR1Existing/
Hybrid Underpass
PM
EBL EBLT* 200 160 30 35 320 195 40 40
EBTR 105 125 120 155
WBL 185 130 270 170
WBTR WBTR* 130 120 25 30 140 135 40 40
NBL 165 115 190 135
NBTR 355 200 455 210
SBL SBLR* 80 70 125 140 90 120 155 165
SBT 175 165 205 210
SBR 100 95 110 210
1. Meadow Drive is the Underpass Alternative
* Movements associated with lower intersection
Rounded up to nearest 5 feet
Bold = exceeding available storage length
RAB = Roundabout | DAR = Direct Access Ramp
2. Average Queues (Feet) – Meadow
13 Alma Street at Meadow Drive
Year 2025 2040
Configuration
Existing Hybrid Underpass
with RAB1
Underpass
with DAR1 Existing Hybrid Underpass
with RAB1
Underpass
with DAR1Existing/
Hybrid Underpass
PM
EBL EBLT* 125 140 30 30 385 185 35 35
EBTR 95 110 130 155
WBL 325 135 835 210
WBTR WBTR* 325 135 30 25 835 210 45 35
NBL 90 110 110 95
NBTR 220 280 270 205
SBL SBLR* 200 105 125 125 255 180 155 155
SBT 495 325 595 495
SBR 95 80 100 80
1. Meadow Drive is the Underpass Alternative
* Movements associated with lower intersection
Rounded up to nearest 5 feet
Bold = exceeding available storage length
RAB = Roundabout | DAR = Direct Access Ramp
2. Approach Delays (Seconds) – Charleston
14 Alma Street at Charleston Road
Year 2025 2040
Configuration Existing Hybrid Underpass
with RAB1
Underpass
with DAR1 Existing Hybrid Underpass
with RAB1
Underpass
with DAR1
AM
Intersection 57.2 E 41.8 D 13.5 B 12.3 B 81.9 F 50.4 D 16.5 B 14.9 B Northbound 73.3 E 39.7 D 13.0 B 11.8 B 118.5 F 45.2 D 16.8 B 14.2 B Southbound 51.1 D 38.1 D 11.8 B 10.7 B 58.5 E 45.2 D 13.3 B 12.6 B Eastbound 13.7 B 47.5 D *** *** 12.7 B 68.7 E *** ***
Westbound 74.3 E 47.8 D 20.4 C 19.3 B 86.8 F 51.6 D 22.9 C 23.5 C PM
Intersection 106.4 F 52.9 D 12.4 B 12.4 B 108.5 F 101.3 F 14.6 B 15.2 B Northbound 48.4 D 47.9 D 11.3 B 11.7 B 55.0 D 75.2 E 12.1 B 12.9 B Southbound 216.2 F 59.1 E 11.0 B 10.9 B 227.2 F 161.9 F 12.3 B 12.3 B Eastbound 13.2 B 52.1 D *** *** 12.6 B 54.5 D *** ***
Westbound 77.9 E 46.7 D 19.2 B 18.4 B 93.7 F 62.7 E 27.2 C 28.5 C
1. Results for Upper Alma and Charleston intersection
*** Movements not allowed at intersection approach
RAB = Roundabout | DAR = Direct Access Ramp
2. Average Queues (Feet) – Charleston
15 Alma Street at Charleston Road
Year 2025 2040
Configuration
Existing Hybrid Underpass
with RAB1
Underpass
with DAR1 Existing Hybrid Underpass
with RAB1
Underpass
with DAR1Existing/
Hybrid Underpass
AM
EBLT 150 190 240 330
EBTR 150 195 250 345
WBLT WBLR* 125 100 115 100 155 115 130 135
WBTR 140 120 245 125
NBL 295 190 1,890 260
NBTR NBTR* 415 330 80 140 610 415 105 230
SBL SBL* 95 80 80 75 125 115 95 95
SBT SBT* 225 215 45 45 260 280 55 55
SBR 75 75 100 110
1. Meadow Drive is the Underpass Alternative
* Movements associated with upper intersection
Rounded up to nearest 5 feet
Bold = exceeding available storage length
RAB = Roundabout | DAR = Direct Access Ramp
2. Average Queues (Feet) – Charleston
16 Alma Street at Charleston Road
Year 2025 2040
Configuration
Existing Hybrid Underpass
with RAB1
Underpass
with DAR1 Existing Hybrid Underpass
with RAB1
Underpass
with DAR1Existing/
Hybrid Underpass
PM
EBLT 150 195 285 275
EBTR 150 200 305 295
WBLT WBLR* 175 120 145 145 235 170 195 200
WBTR 200 140 245 200
NBL 105 120 140 195
NBTR NBTR* 205 185 50 105 250 270 55 120
SBL SBL* 115 95 70 70 120 105 10 80
SBT SBT* 1,420 390 110 110 1,560 1,350 135 135
SBR 95 65 85 85
1. Meadow Drive is the Underpass Alternative
* Movements associated with upper intersection
Rounded up to the nearest 5 feet
Bold = exceeding available storage length
RAB = Roundabout | DAR = Direct Access Ramp
3. Vehicle Travel Times (Seconds)
Meadow Drive Redirected Movements
17 Year 2025 2040
Configuration Existing Hybrid Underpass Existing Hybrid Underpass AM
Northbound to Eastbound 65 60 130 80 55 130
Northbound to Westbound 185 120 130 240 135 135
PM
Northbound to Eastbound 55 60 140 55 55 140
Northbound to Westbound 130 110 140 135 110 145
1. Assumes Charleston Road is the underpass alternative
2. Travel Times rounded up to the nearest 5 seconds
UNDERPASS
UNDERPASS
18 Meadow Drive: Underpass
Northbound Alma Street to
East/Westbound Meadow Drive via Ramp
PARK BLVD
ALMA STALMA ST
PARK BLVD
3. Vehicle Travel Times (Seconds)
Charleston Road Redirected Movements
19 Year 2025 Scenarios 2040 Scenarios
Configuration Existing Hybrid Underpass
with RAB2
Underpass
with DAR2 Existing Hybrid Underpass
with RAB2
Underpass
with DAR2
A
M
Eastbound to Northbound 60 95 135 135 60 115 135 145
Northbound to Westbound 200 90 135 70 95 95 150 75
Southbound to Westbound 65 60 165 155 65 65 180 165
P
M
Eastbound to Northbound 60 100 135 135 60 105 145 145
Northbound to Westbound 120 140 125 65 135 210 130 70
Southbound to Westbound 225 85 160 155 230 180 165 165
1. Assumes Meadow Drive is the underpass alternative
2. RAB = Roundabout | DAR = Direct Access Ramp
3. Travel Times rounded up to the nearest 5 seconds
20 CHARLESTON RD
PARK BLVD
ALMA ST
GREENMEADOW WAY
MUMFORD PL
ELY PL
Wilkie Way
UNDERPASS
Charleston Road:
Underpass with Roundabout
Eastbound Charleston Road (at Wilkie Way)
toNorthbound Alma Street (at Lindero Drive)
21 CHARLESTON RD
PARK BLVD
ALMA ST
GREENMEADOW WAY
MUMFORD PL
ELY PL
Wilkie Way
UNDERPASS
Charleston Road:
Underpass with Roundabout
Northbound Alma Street (at Ely Place) to
Westbound Charleston Road (at Wilkie Way)
CHARLESTON RD
PARK BLVD
ALMA ST
GREENMEADOW WAY
MUMFORD PL
ELY PL
Wilkie Way
UNDERPASS
Charleston Road:
Underpass with Roundabout
Southbound Alma Street (at Lindero Drive) to
Westbound Charleston Road (at Wilkie Way)
3. Bicycle Travel Times (Seconds)
Meadow Drive
23 Year 2025 2040
Configuration Existing Hybrid Underpass Existing Hybrid Underpass AM
Southbound to Eastbound 120 130 130 115 140 130
Southbound to Northbound 135 155 195 130 165 195
Westbound to Northbound 105 100 150 110 100 150
PM
Southbound to Eastbound 115 125 130 110 140 130
Southbound to Northbound 135 155 195 130 165 195
Westbound to Northbound 115 100 145 125 105 150
1. Assumes Charleston Road is the underpass alternative
2. RAB = Roundabout | DAR = Direct Access Ramp
3. Travel Times rounded up to the nearest 5 seconds
UNDERPASS
UNDERPASS
24 Meadow Drive: Underpass
Southbound Park Boulevard (at Maclane St)
to Eastbound Meadow Drive (at Emerson St)
PARK BLVD
ALMA STALMA ST
PARK BLVD
UNDERPASS
UNDERPASS
25 Meadow Drive: Underpass
Southbound Park Boulevard (at Maclane St)
to Northbound Alma Street (at Alma Village)
PARK BLVD
ALMA STALMA ST
PARK BLVD
UNDERPASS
UNDERPASS
26 Meadow Drive: Underpass
Westbound Meadow Drive (at Emerson St) to
Northbound Park Boulevard (at Maclane St)
ALMA STALMA ST
PARK BLVD
PARK BLVD
3. Bicycle Travel Times (Seconds)
Charleston Road
27 Year 2025 2040
Configuration Existing Hybrid Underpass
with RAB2
Underpass
with DAR2 Existing Hybrid Underpass
with RAB2
Underpass
with DAR2
AM
Southbound to Eastbound 100 110 95 95 110 125 95 95
Southbound to Northbound 125 135 125 125 135 150 125 125 Westbound to Northbound 110 95 95 95 115 95 95 95
PM
Southbound to Eastbound 95 105 95 95 165 130 95 95
Southbound to Northbound 120 130 125 125 185 155 125 125 Westbound to Northbound 110 95 95 95 120 100 95 95
1. Assumes Meadow Drive is the underpass alternative
2. RAB = Roundabout | DAR = Direct Access Ramp
3. Travel Times rounded up to the nearest 5 seconds
ALMA ST
UNDERPASS
Charleston Road:
Underpass with Roundabout or DAR
Southbound Park Blvd (at Carolina Ln) to
Eastbound Charleston Road (at Wright Pl)
CHARLESTON RD
ALMA ST
UNDERPASS
Charleston Road:
Underpass with Roundabout or DAR
Southbound Park Blvd (at Carolina Ln)
to Northbound Alma St (at Lindero Dr)
CHARLESTON RD
ALMA ST
ALMA ST
UNDERPASS
Charleston Road:
Underpass with Roundabout or DAR
Westbound Charleston Rd (at Wright Pl)
To Northbound Park Blvd (at Carolina Ln)
CHARLESTON RD
ALMA ST
ALMA ST
PARK BLVD
Churchill Avenue
1. Configuration
• Advance Partial Underpass (LPA)
2. Partial Underpass Landscape Strip
• With OR Without
3. Seale Avenue Bicycle and Pedestrian Crossing
• Seale Avenue Ramp OR Alma Street Ramp
• Rail Committee recommended to eliminate the Seale Avenue Ramp City Council Motion – Churchill Avenue
31 City Council to identify which alternatives to advance to 15% design in preparation for environmental review
City Council Motion – Meadow & Charleston
32 City Council to identify which alternatives to advance to 15% design in preparation for environmental review
Meadow Drive
• Hybrid OR Underpass OR Both
Charleston Road
• Hybrid OR Underpass OR Both
• Underpass
• Roundabout OR Direct Access Ramp
Thank You