If electronic signs on Military Cutoff, Oleander Drive, and Eastwood Road displayed “WB Public Parking FULL,” how many cars would be deterred from crossing the bridge? Here’s an estimation based on realistic assumptions.

• Peak inbound demand (4 hrs): ≈ 7,000 vehicles ​

• Average inbound flow: ≈ 1,750 vehicles/hour ​

• Beach-bound share: ≈ 70% ​

• Drivers exposed to signage: ≈ 85% ​

• Behavior change (deterrence): 5–20%

Scenario: Conservative (5%)
Cars Deterred per Hour: ≈ 50
Cars Deterred (4 hrs): ≈ 200

Scenario: Moderate (10%)
Cars Deterred per Hour: ≈ 100
Cars Deterred (4 hrs): ≈ 400

Scenario: Agressive (20%)
Cars Deterred per Hour: ≈ 200
Cars Deterred (4 hrs): ≈ 800

• Even modest deterrence (~100 cars/hour) reduces bridge backups by about 1,000 feet per cycle. 

• Signs are most effective when they provide real-time, credible updates. 

• Messages paired with pricing or enforcement reminders are more likely to change driver behavior. 

• Signs without trusted data risk being ignored, dropping impact toward the low end (5%).

1. Use real-time meter data to drive sign updates. 

2. Add time-specific guidance (e.g., "likely available after 3 PM"). 

3. Coordinate with navigation apps to extend reach. 

4. Pair with pricing or enforcement notices for credibility.