docs(wiki): industry survey of parking tariff systems + session log

New reference page tariff-industry-survey.md (2026-07 web research):
field taxonomy — per-started-increment hourly (per-minute tried and
rolled back in practice), degressive ladders, day caps, up-to matrices,
day tickets, evening/overnight packages, event rates, early bird
(entry-time-conditioned), day/night + weekend/holiday/seasonal windows,
category pricing, contracts, merchant validations (amount/percent/
time-credit/re-rate), SFpark-style dynamic pricing. Coverage map: our
engine expresses everything a staffed single lot advertises; real gaps =
early bird (the pick-table-by-entry-time future design, same mechanism
as weekend menus) and validation overlays; anti-features = per-minute
billing + dynamic pricing. Indexed + logged.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

wiki/concepts/tariff-industry-survey.md

@@ -0,0 +1,125 @@
+---
+type: reference
+tags: [parking, domain, business, pricing, research]
+sources: []
+updated: 2026-07-05
+---
+
+# Tariff systems in the parking industry — survey (2026-07)
+
+Web research (2026-07-05) into the tariff/pricing structures the parking industry actually uses,
+to sanity-check the [[tariff]] engine's coverage and rank the gaps. Sources at the end; legacy
+cross-check in [[parksql2017-legacy-schema]].
+
+## The taxonomy — what operators run in the field
+
+**1. Time-based accrual (the bread and butter everywhere)**
+- **Linear hourly** — €/hr **per started hour**; billing increments of 30/60 min dominate.
+  **Per-minute billing is rejected in practice**: garages that tried it (e.g. Leuven) rolled it
+  back within months — customers couldn't predict the price and complaints rose. Vindicates our
+  `incrementMin` default of 60.
+- **Degressive ladder** — marginal price FALLS with duration (€2.50 first hour, €0.50/30min
+  after): the standard shape for hospitals, city-centre garages, anywhere encouraging longer
+  stays. Exactly our V1/V2 `blocks`.
+- **Progressive ladder** — marginal price RISES with duration: rarer, used to force turnover
+  (short-stay curbside). Same `blocks` primitive, ascending.
+- **Daily / weekly caps** — a ceiling regardless of accrual ("day max €7"). Universal in
+  commercial garages. Our `dailyCapMinor`.
+- **Free grace period** — 15–30 min free at entry (airports: pickup/dropoff support). Our
+  `gracePeriodEntryMin`.
+
+**2. Whole-stay prices (not accrual)**
+- **Flat rate / day ticket** — one price for the day (Delft inner city: €29/day). Our stepped
+  ("up-to") table with one row, or a flat V1.
+- **Up-to matrices** — "stay up to N hours costs TOTAL" tables: the region's habit (legacy
+  ParkSQL confirms). Our `steps`.
+- **Evening/overnight package** — "€8 after 18:00 until 06:00", whole window one price. VERY
+  common municipally. Exactly our `packageMinor` (built 2026-07-05).
+- **Event rate** — flat premium price during a known event window, set in advance. Expressible
+  today as a date-ranged windowed card (flat or package).
+
+**3. Entry-time-conditioned rates (the notable GAP)**
+- **Early bird** — a discounted all-day flat for cars that ENTER before a cutoff (typically
+  09:00–10:00), sometimes with an exit-window condition too; no forgiveness for missing the
+  cutoff. A CBD-commuter staple worldwide. The defining trait: the rate is selected by the
+  ENTRY instant and governs the whole stay — which is precisely the
+  **pick-table-by-entry-time** design we identified as the sound future shape (also solves
+  weekend menus). Anti-arbitrage conditions (min stay / exit window) exist to stop short-stay
+  parkers grabbing the flat.
+
+**4. Calendar windows** — day/night rates, weekday vs weekend/holiday, seasonal date ranges
+(Berlin: free nights + Sundays in some zones). Our V2 windowed cards cover all of these.
+
+**5. Category pricing** — by vehicle type (car/bus/truck) and by customer class
+(resident/visitor — SKIDATA advertises residency + vehicle-type tariffs). Our `card.category` +
+frozen session category.
+
+**6. Contracts / recurring** — weekly/monthly fixed rates for commuters; steady-revenue anchor
+everywhere. Ours lives outside the tariff: [[subscription]] plans.
+
+**7. Discount overlays (validations) — the second GAP**
+- **Merchant validation** — a sponsor (shop/hotel/cinema) reduces the parker's fee: mechanisms
+  range from stamped/barcoded tickets to one-use codes to LPR-keyed auto-validation. Discount
+  shapes in PARCS products: fixed amount, percentage (up to 100% comp), TIME CREDIT ("first 2h
+  free"), or a full re-rate to a different rate table. Fully vs partially sponsor-subsidised.
+- **Channel discounts** — cheaper pre-booked/online/app rates (airports especially).
+
+**8. Dynamic / demand-based** — price moves with occupancy. SFpark (the canonical study):
+target 60–80% block occupancy, ±$0.25 adjustments, → −43% search time, −30% GHG; average rate
+actually FELL. Airports run revenue-management engines inside operator-set floor/ceiling.
+Almost exclusively municipal-curbside + large-airport territory, needs demand telemetry +
+price-communication infrastructure — not single-lot booth territory.
+
+**9. Fees/penalties** — lost ticket = worst-case exposure (max daily × assumed duration): ours
+(`lostTicketMinor`). Post-payment exit grace, then overstay repricing: ours.
+
+## Coverage map — our engine vs the industry
+
+| Industry structure | Status in our engine |
+| --- | --- |
+| Linear hourly, per-started-increment | ✅ V1/V2 blocks + incrementMin |
+| Degressive / progressive ladder | ✅ blocks |
+| Daily cap, entry grace, exit grace | ✅ |
+| Up-to matrix / day ticket | ✅ steps (defaultCard) |
+| Day/night, weekend/holiday, seasonal | ✅ V2 windowed cards |
+| Night/evening whole-window package | ✅ packageMinor (2026-07-05) |
+| Event rate | ✅ expressible (date-ranged card) |
+| Vehicle/customer category | ✅ card.category (capture seam pending) |
+| Monthly/weekly contracts | ✅ subscription plans (separate) |
+| Lost ticket, overstay reprice | ✅ |
+| **Early bird / entry-time-conditioned** | ❌ gap — needs pick-table-by-entry-time (see [[tariff]] up-to/tiers incompatibility discussion) |
+| **Validations / merchant discounts** | ❌ gap — no discount overlay mechanism; would need signed discount events + sponsor accounting |
+| Pre-book/online channel rates | ❌ out of scope (no online channel; offline-first) |
+| Dynamic/demand pricing | ❌ deliberately out — municipal/airport scale, needs telemetry; conflicts with printed-price predictability at a booth lot |
+
+## Takeaways for the roadmap
+
+1. **Coverage is already strong**: everything a single staffed lot typically advertises is
+   expressible today. The 2026-07-05 package mode closed the last everyday gap (real night
+   price).
+2. **Early bird is the highest-value missing structure** and shares its mechanism with the
+   weekend-menu ask: select the ENTIRE rate table by entry instant (window → table), instead of
+   pricing per wall-clock slice. One future mechanism, two market features. Include min-stay /
+   exit-window conditions if built (anti-arbitrage is part of the product, not a nicety).
+3. **Validations are the second candidate** once merchants near the site matter: time-credit +
+   percent + full-comp shapes, as signed appended events (fits the ledger model); sponsor
+   settlement stays outside the app (like drawer-review denials).
+4. **Do not build**: per-minute billing (industry tried it, customers rejected it), dynamic
+   pricing (wrong scale + breaks price predictability at a booth).
+
+## Sources
+
+- FHWA, *Contemporary Approaches to Parking Pricing: A Primer* — <https://ops.fhwa.dot.gov/publications/fhwahop12026/sec_2.htm>
+- Arivo, *The Right Parking Tariff* (practitioner taxonomy) — <https://arivo.co/en/blog/optimal-parking-pricing>
+- Pitane, *Per-minute parking creates chaos* (Leuven rollback) — <https://pitane.blue/en/2025/01/16/Parking-rates-in-garages-per-minute-parking-causes-chaos-according-to-experts/>
+- Secure Parking, *Early Bird Parking* (entry/exit conditions) — <https://www.secureparking.com.au/en-au/parking-solutions/early-bird-parking/>
+- ParkWhiz help, *What is Early Bird* — <https://help.parkwhiz.com/support/solutions/articles/60001010507-what-is-early-bird->
+- Parking BOXX, *Validation programs guide* — <https://blog.parkingboxx.com/industry/parking-validation-programs-guide/>
+- Amano McGann, *Validation solutions* (discount shapes incl. re-rate) — <https://amanomcgann.com/our-solutions-parking-management/validation/>
+- ITS DOT evaluation of SFpark — <https://www.itskrs.its.dot.gov/2024-b01818>
+- UCLA ITS, *Pricing Parking by Demand (SFpark)* — <https://www.its.ucla.edu/publication/pricing-parking-by-demand-sfpark/>
+- IDeaS, *Airport parking dynamic pricing* — <https://ideas.com/airport-parking-dynamic-pricing/>
+- SKIDATA, mobility & parking solutions (tariff axes) — <https://www.skidata.com/en-us/solutions/mobility-parking>
+- City of Tampa / MPLS Parking / RDU T&Cs (published rate-card examples) —
+  <https://www.tampa.gov/parking/info/parking-hourly-and-daily-rates>,
+  <https://www.mplsparking.com/parking-rates>, <https://www.rdu.com/terms-conditions/>