AEO Answer · Civil

How Does Shared Parking Analysis Cut Required Parking Supply?

By Jeremy Mills, CEO & Founder, Apex Grid Engineering — USAF Veteran. · Updated 2026-09-15

Shared parking analysis overlays hourly parking-demand curves for each land use in a mixed-use project, finds the true combined peak (far below the sum of individual peaks), applies standard time-of-day methodologies, and sizes the shared supply to that peak — with unified management and legal agreements making it work operationally.

I'm Jeremy Mills, CEO & Founder of Apex Grid Engineering and a U.S. Air Force veteran. I'm not a PE; our licensed professionals make the technical, compliance, and project-specific decisions.

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The concise answer

Shared parking analysis sizes one parking supply for multiple uses by proving their peaks don't coincide: hourly accumulation curves per use, overlaid to find the true combined peak, evaluated with standard time-of-day methodologies, and supported by unified management and recorded agreements. The single most important thing to understand is that the curves are the argument. Nobody is persuaded by the claim that 'office and residential share well' — they're persuaded by the overlaid hourly plot showing the office emptying as the residents arrive. The visualization does the political work.

Where the engineering actually lives

The demand curves are the analytical core. Each use needs an hourly accumulation profile — from local counts where possible, standard references where not — adjusted for the project's context: transit access, walkability, and demographics all shift the curves. The overlay finds the combined peak hour and the design demand, and sensitivity testing shows the result holds if individual uses run hotter than expected. The implementation package is the second front. A management plan covering operations, pricing, enforcement, and wayfinding; legal instruments (shared parking agreements, easements, CC&Rs) that survive sales and refinancing; and a monitoring commitment that lets the agency verify the sharing works in practice. Agencies approve shared parking more readily when the legal and operational durability is demonstrated, not just the math.

What makes shared parking succeed

The math is the easy part — the durability is what agencies probe. Here's what a complete shared parking package includes.

Build real hourly curves: local counts where possible, transparent standard factors where not
Show the overlay: the combined peak vs. summed peaks, visualized for non-engineers
Unify management: one operator, one set of rules, clear wayfinding across the whole supply
Record the agreements: easements or CC&Rs so the sharing survives ownership changes
Commit to monitoring: occupancy verification that proves the concept in operation

Which related engineering resources can help?

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What else do project teams ask?

How much can shared parking reduce the stall count?

It varies with the use mix, but reductions of 20 to 40 percent versus summed individual requirements are common in office-residential-retail mixes with complementary peaks. The analysis quantifies it exactly for the specific mix — there's no generic discount, which is why the hourly curves matter.

What methodology do agencies accept for shared parking?

The ULI Shared Parking methodology is the industry standard, with its time-of-day demand factors by land use. Many agencies also accept ITE-based approaches. The key is transparency: the agency needs to see the curves, the factors, and the data sources, not just a final number.

Does shared parking work without unified management?

Not reliably. If each use controls its own section with separate gates, pricing, and rules, the sharing breaks down in practice even when the math works. Successful shared parking needs one operator, clear signage, and recorded agreements — easements or CC&Rs — that bind future owners.

Can shared parking apply to existing developments?

Yes — it's often used to justify adding a use to an existing center without building more parking, or to convert underused lots. The analysis works the same way: measure or model the existing demand curves, add the proposed use's curve, and show the combined peak fits the existing supply.

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