Week 4 — The Curb Productivity Scale: Why Pricing-Only Reform Stalls at Type II

There is a Bortle scale for night skies, a Saffir-Simpson scale for hurricanes, and a Kardashev scale for civilizations. Each describes a phenomenon as a small set of clearly defined levels with criteria any observer can apply. None of them are exact. All of them are useful, because they let us compare across cases and talk about progress.

There is no such scale for the curb. There is no shared vocabulary that tells a city how its curb stacks up against its peers, where it sits on a developmental arc, or what graduating to the next level would actually require. Without one, every conversation about parking technology becomes a feature checklist and an RFP.

We propose the Curb Productivity Scale (CPS) — a five-level classification, Type 0 through Type IV, defined across six dimensions: Policy, Data availability, Wayfinding, Decision-Point Information, Transaction ease, and Enforcement. A city’s level on the scale is the level of its weakest dimension. Two design rules keep the scale honest. First, a city’s overall level is the minimum of its dimension scores — demand-responsive pricing without dynamic signage is a billing trick that does not move you up, because the driver cannot act on what the algorithm decided. Second, the levels are observable from the curb — a driver standing at a space should be able to tell what level the city is at by what is or is not on the sign, the meter, the app, and the corridor wayfinding.

The reason this matters for a Shoup-aligned reform conversation is that the cities held up as exemplars — SFpark, LA Express Park, Seattle, Pittsburgh — operate at Type II overall. They have reached Type III on the Policy dimension with demand-responsive pricing on flagship corridors. The other five dimensions trail. SFpark and LA Express Park both decommissioned their per-space pavement sensors years ago and now infer occupancy from transaction data. Decision-point information remains a smart meter face showing the rate; per-space dynamic indicators with live time-limit enforcement do not exist. Enforcement is officer-driven with handheld assistance, not LPR-based exception dispatch. Under the minimum-of-dimensions rule, even the exemplars are Type II overall — Type III policy on a Type II foundation.

This is the essential thing the CPS framework reveals that the pure pricing argument cannot. A city can do Shoup’s reform — implement demand-responsive pricing, return revenue to the district — and remain stuck at Type II overall because the supporting layers have not caught up. The pricing reform does not deliver its full potential, because the information environment does not let it.

The economic gap between Type II and Type III, on a midsize downtown of 1,500 metered spaces, is on the order of fifty to ninety million dollars a year in foregone commerce. That is not a procurement decision. It is a strategic-planning decision the parking-reform conversation has not, until recently, named.

There is a third option many cities have drifted into when trying to reach beyond Type II without solving the signage problem: differentiated rules — zoned, time-of-day, mixed limits — with the rule disclosure pulled away from the curb into a kiosk or a phone app. The rules exist. They are enforced. But they are not visible at the moment of decision. We call this the third-option trap: complex policy with informationally austere driver experience. Operationally complex. Communicatively opaque. Corrosive to public trust. We will spend Week 5 on why this pattern has emerged in post-Shoup parking technology and why it is the wrong direction.

For now, the practical takeaway. The CPS framework tells a city three useful things: where it currently stands across each dimension; where the gap between dimensions lies (this is almost always between policy ambition and information delivery); and what graduating to Type III actually requires. The technology preconditions are dynamic at-space signage, per-space occupancy sensing, app integration that places “what does this space cost me right now?” in the driver’s pocket and on the device at the same time, multi-channel transaction at the space, and LPR-based exception-dispatch enforcement. The capital required is real. On a 1,500-space midsize downtown the order of magnitude is five to fifteen million dollars. The recovery period — based on the commerce uplift — is short. Most Type II to Type III investments pay back inside eighteen months.

The CPS scale is what Shoup’s framework needs to move from principle to operational sequence. It is also, we hope, what the parking-reform conversation needs to move from RFP-by-feature to investment-by-stage.

Next week: The post-Shoup detour — convenient for whom?