How the Screening Works
A transparent, rule-based model compares candidate public EV charging sites, sizes a starter installation for each, and flags what needs review before any decision moves forward. It supports planning; it approves nothing.
The Nine Steps
The model is built for public-sector planners and local government staff. It helps them compare candidate sites side by side, pick starter candidates, see where future expansion may be needed, and spot administrative or engineering review issues early.
It runs as a fixed sequence, so every result can be traced back through these steps. Open a step to read what happens there.
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Candidate public EV charging locations are loaded into the model. This run covers twelve sites in Fairfax and Prince William County.
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Each site is described with planning-screen inputs such as site type, public access, operating hours, parking context, nearby charging supply and electrical assumptions.
What Goes In -
The model evaluates demand, electrical and cost feasibility, accessibility, public value, safety and review burden, and future readiness.
How Sites Are Scored -
Each candidate receives a planning-support readiness score. The score exists for comparison between sites, not as a measure of approval.
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Scores and review signals are translated into planning categories: advance, expandable starter, resolve review issues, monitor, or do not advance yet.
Decision Categories -
The model separates install-now ports from future-ready capacity, so a site can start small without closing off growth.
Right-Sizing Ports -
The model identifies fields or site conditions that need confirmation before implementation decisions.
Baseline Check -
Alternative future-demand conditions are tested to see whether future-ready capacity remains adequate.
Scenario Testing -
The model exports site rankings, decision buckets, Tableau-ready files, scenario results and the generated PDF planning report.
Outputs and Limits
What Goes In
Each site is described by planning-screen inputs in six groups. They are early-stage planning attributes: some still need formal confirmation, and none is treated as final, verified engineering data.
Inputs stay private. Only outputs are published.
The real values behind these inputs, such as electrical service ratings, spare capacity, visitor and employee counts and parking counts, appear nowhere on this site. Pages show only what the model produces: ranks, scores, categories, port plans and review needs.
- Site identitySite ID, site name and jurisdiction.
- Context and usePublic-serving use type, operating hours and parking context.
- Demand proxiesHouseholds and jobs nearby, traffic on the nearest arterial, nearby amenities, local EV share and the charging already nearby. Visitor and employee counts size the number of ports; they do not change the readiness score.
- InfrastructureLikely charger placement, electrical service rating and spare electrical capacity.
- Safety and complianceADA and accessibility considerations, emergency disconnect visibility, garage and structure-specific needs, fire and AHJ indicators, and stormwater and site-work indicators.
- Testing conditionsFuture demand scenarios.
How Sites Are Scored
Each site is evaluated, qualitatively and systematically, across six high-level dimensions. The result is the readiness score used to compare sites. No weights for the dimensions are published.
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Demand signal
Whether the site looks likely to support enough public charging demand, judged from its surroundings (households, jobs, traffic, amenities, local EV share), its parking, hours and visit length, and the charging already nearby.
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Electrical and cost feasibility
Whether the site's electrical capacity, service constraints and likely implementation complexity support immediate readiness or pose heavy upgrade burdens.
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Accessibility and site suitability
Whether site access, ADA spacing, parking layout and likely charger placement are viable.
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Public value and equity
Whether the site supports useful public access, serves its community context well and offers strategic planning value.
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Safety, review and implementation burden
Whether AHJ review, fire codes, structured-parking rules, emergency disconnect visibility or stormwater impacts may complicate or slow implementation.
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Future readiness and scenario sensitivity
Whether the site appears structurally and spatially able to support future demand growth under varying planning scenarios.
Decision Categories
The scores and review signals sort every site into one of five categories. The categories help a team triage quickly: which sites warrant detailed engineering study now, and which should wait.
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Tier 1
Advance as strong starter candidates
The strongest current starter candidates in the model, with solid demand and lower implementation friction.
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Tier 2
Good starter candidates with expandable design
These sites may support a starter installation well, but should be planned carefully with future expansion and verification in mind.
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High review
Resolve review issues before expansion
These sites may be useful public assets, but significant review burdens or electrical constraints should be addressed before committing to major capacity.
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Tier 3
Monitor or run a small pilot
These sites should be monitored over time, or considered only for smaller pilot-style planning rather than immediate general expansion.
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Special use
Do not advance for general-public buildout yet
The site should not advance as a general-public charging site unless its foundational assumptions change, for example its public access hours or a fleet-only use case.
Right-Sizing Ports
The aim is to avoid overbuilding while still preparing each site for growth. The model does this by splitting capacity into two recommendations.
25
Install-now ports
A smaller starter recommendation based on immediate feasibility, electrical capacity and modeled current demand.
48
Future-ready ports
The capacity a site should be prepared to accommodate if demand grows, such as conduit, panel space and spatial planning.
Each square is one port. A site's full row is its future-ready total; filled squares are installed now.
Loading the per-site port plan.
Three things to know about the published plan
- It follows the
legacy_v2ranking. The port plan uses the study's acceptedlegacy_v2ranking rather than the canonicalmilestone2_v3ranking shown on the results pages, so its totals of 25 install-now and 48 future-ready ports reconcile with what was presented. On the canonical ranking, the same rules give 25 and 47. - Every site gets at least 2 install-now ports. That includes the Public Safety Training Center (PWC003), where the advice is not to advance a public buildout until the use case is confirmed. Its 2 ports are counted in the total as a placeholder, not as a recommendation.
- Chinn Park Regional Library (PWC004) was closed for renovation when the site data were gathered in June 2026. Its rank and plan assume it reopens much as it was.
Right-sizing is a planning-support recommendation. It must always be checked against engineering, utility, procurement, site design, ADA and permitting review. Electrical capacity is an unverified placeholder at all twelve sites.
Scenario Testing
To check that future-ready recommendations hold up, the model tests whether the future-ready capacity stays adequate under different simulated planning conditions. These six scenarios come from the legacy_v2 sweep.
- BaseDemand grows 1.9 times by 2036, 3.0 times by 2046 and 4.0 times by 2056.No gaps
- High growthDemand grows 2.6 times by 2036, 4.5 times by 2046 and 6.0 times by 2056.No gaps
- Long sessionsFrom the legacy_v2 sweep. Parameters are not published here.No gaps
- Short daily windowFrom the legacy_v2 sweep. Parameters are not published here.No gaps
- Peakier demandFrom the legacy_v2 sweep. Parameters are not published here.No gaps
- Combined stressHigh growth plus a further 15 percent at every horizon.2 gaps
In the legacy_v2 sweep, the first five scenarios showed no future-ready capacity gaps at any site, and combined stress opened two minor gaps of one port each. The growth figures listed are the canonical milestone2_v3 definitions of the same names; they are provisional planning conventions, not yet calibrated to observed charging data.
The canonical milestone2_v3 contract carries four scenario names: baseline, base, high and stress_combined.
Baseline Check
The legacy_v2 baseline run of the prototype, across the Fairfax and Prince William County candidates, produced these results.
- Candidate sites evaluated
- 12
- Tier 1 starter candidates
- 2
- Decision categories applied
- 5
- Tableau-ready data exports
- 15
- Blocking validation errors
- 0
- Warnings
- 0
- Review flags to confirm
- 38
- Info items
- 12
Review flags are not failures
The run has zero blocking validation errors. Each of the 38 review flags marks a field that needs more information or administrative confirmation from local staff before detailed design can proceed. The fields that recur most are:
- Electrical service ratings
- Spare electrical capacity
- Emergency disconnect visibility
- Visitor and employee counts
- Operating hours
- Parking counts
- Likely charger placement
- Garage, fire, AHJ and access reviews at special-use sites
Outputs and Limits
What It Produces
- Public EV Charging Planning Report (PDF)
- Site rankings
- Decision buckets
- Port recommendations
- Scenario results
- Visual summaries
- Tableau-ready CSV exports
What It Does Not Replace
- Final engineering design
- Utility coordination
- Formal permitting
- Procurement processes
- ADA compliance review
- Fire and AHJ review
- Stormwater review
- Construction approval
- On-the-ground site surveys
- Stakeholder confirmation
- Official municipal decision-making