Grand Army Plaza Workshop Materials — Vehicle Flow Analysis, April 2026

Detailed vehicle flow diagrams showing current conditions vs. proposed design for each approach road.

Union Street Vehicle Flows

• 14% of vehicles using the entire plaza originate from Union Street
• Current: One decision point for most movements creates confusion and unexpected lane changes
• Proposed: Two dispersed decision points with more typical lane changes

Flatbush Avenue (South) Vehicle Flows

• 1,874 vehicles in morning peak hour
• 23% of vehicles using the entire plaza originate from Flatbush (South)
• Traffic distribution: 15.1% to Flatbush (North), 4.7% to Union St, 0.6% to Eastern Parkway, 0.8% to Prospect Park W
• Current: One decision point creates confusion
• Proposed: Two dispersed decision points

Flatbush Avenue (North) Vehicle Flows

• 1,867 vehicles in morning peak hour
• 23% of vehicles using the entire plaza originate from Flatbush (North)
• Current: One decision point creates confusion
• Proposed: Two dispersed decision points

Eastern Parkway Vehicle Flows

• 2,480 vehicles in morning peak hour
• 31% of vehicles using the entire plaza originate from Eastern Parkway
• Traffic distribution: 15.7% to Union St, 1.6% to Flatbush (North), 11.5% to Vanderbilt Ave, 2% to Prospect Park W

Vanderbilt Avenue Vehicle Flows

• 722 vehicles in morning peak hour
• 9% of vehicles using the entire plaza originate from Vanderbilt Ave
• Current: One decision point creates confusion
• Proposed: Two dispersed decision points

Grand Army Plaza Injury Summary, 2020–2025 (5 years)

Category	Total Injuries	Severe	Fatalities	KSI
Pedestrian	8	0	0	0
Bicyclists	14	3	0	3
Motor Vehicle Occupant	184	1	0	1
Motorized Two-Wheelers	13	1	0	1
Total	219	4	0	4

Vision Zero Corridors: Flatbush Ave, Eastern Parkway, and St. Johns Place