Curb Conflict and Freight Externalities

Headline Findings

Dwell time violations and double-parking are endemic in US cities. NYC DOT data reveals that loading activities consume kerb space at rates far exceeding permitted dwell times, with 65% of deliveries concentrated in peak morning hours (before noon). Loading zones—when provided—reduce double-parking by up to 70%, but this solution scales poorly as delivery volumes grow. The allocation failure mode is already evident: insufficient kerb supply, competing uses (passenger, freight, TNC, CAM), and inadequate enforcement create persistent externalities.

Key Numbers

• At least 1 travel lane blocked by double-parked delivery vehicles for ~25% of the day on monitored Brooklyn streets (NYC DOT Church Avenue study)
• 65% of deliveries occur before noon, creating peak dwell-time conflicts
• Loading zones reduce double-parking by up to 70% (NYC DOT finding), but cities have installed only ~500 new zones citywide
• Truck deliveries account for 89% of goods moved in NYC, with e-commerce growth significantly increasing dwell time pressure
• Kerb conflict costs are not directly quantified in available studies, but indirect evidence (enforcement resources, congestion, emergency vehicle delays) suggests substantial externalities

Source Data

NACTO Curb Data Initiative & Curb Data Specification (CDS)

• The Curb Data Specification includes a Metrics API that standardizes measurement of dwell time, occupancy, usage, and enforcement violations
• NACTO identifies three competing uses: passenger vehicles, freight/TNC services, and new mobility options (scooters, bikes)
• Sensor technologies can distinguish vehicle types and measure dwell duration for each category
• Status: CDS exists as specification but city adoption remains fragmented; real-time enforcement linked to CDS data is limited

NYC DOT Delivery Studies

• Urban Freight Case Studies - New York City: Church Avenue study documenting travel lane blockage and dwell patterns
• NYC DOT Neighborhood Loading Zones: Performance data on loading zone deployment in Manhattan
• NYC DOT Installs 500+ Loading Zones: 2024 report on double-parking reduction and zone impact
• Improving the Efficiency of Truck Deliveries in NYC: Policy analysis of dwell-time externalities

Drafting Notes for Chapter 5

Framing the allocation failure:

• Ch.5 should establish that the kerb is fundamentally over-subscribed in dense urban areas
• Current regulatory tools (time limits, permit systems, loading zones) address symptoms but not root cause
• If CAM fleets compete for kerb access (idle vehicles waiting for rides, multiple short dwell cycles), this will exacerbate the allocation failure
• Key argument: Without explicit CAM kerb governance (demand caps, time-based pricing, spatial reservation), CAM will hollow out available kerb for essential functions (freight, emergency access, transit)

Evidence integration:

• Use NYC double-parking rates and dwell time violations as a baseline of allocation failure in current transportation system
• Emphasize that 65% morning concentration + truck delivery necessity creates an “impossible scheduling” scenario
• Show that loading zones (70% double-parking reduction) are a band-aid solution that doesn’t solve the underlying scarcity