Plan of work

Working task list for this piece — the index.md article is the writeup; this is the status tracker.

Done

• Tax incentives — see 01-tax-incentives.md
• Model & TCO survey — see 02-model-tco-survey.md
• First-cut new-car price vs. range chart (22 trims) — see 03-price-range-sketch.html
• Secondhand market survey — see 04-secondhand-market-survey.md
• Secondhand price-band chart, Tesla by trim tier — see 05-secondhand-price-bands.html
• Price-vs-mileage Pareto sketch — see 06-secondhand-price-vs-mileage.html
• Worked case study: Model Y vs. Model 3 secondhand + pricing a real LeBonCoin listing — see 07-reading-a-real-listing.md
• Stub: why it's hard to tell if a used car is a good deal — see 08-why-buying-a-used-car-is-hard.md
• Two concrete recommendation tracks in index.md — budget/secondhand/short-range vs. nicer everyday family car — replacing the earlier single-list recommendation
• Extended secondhand survey to the budget segment: Fiat 500e has a real (and wide) secondhand market; confirmed Twingo E-Tech and ë-C3 are too new to have one yet — see 04-secondhand-market-survey.md
• EV vs. petrol (ICE) total cost of ownership, purchase price + depreciation + running costs together — see 09-ev-vs-ice-total-cost.md
• Euro NCAP safety pass on the budget/family shortlist — decisive, reshuffled the list: Leaf (5★) top pick, Fiat 500e (4★) second, Dacia Spring/Zoe (1★/0★) ruled out despite price — see 04-secondhand-market-survey.md
• Budget-track recommendation confirmed: secondhand Nissan Leaf, per real annual mileage (~10,000km/yr, confirmed low-mileage isn't a risk to the EV-vs-ICE case) and home-charging-dependent range math
• Added BYD Dolphin Surf and Peugeot e-208 to the safety pass — both also 5★, genuinely competing with the Leaf recommendation, not just fallbacks
• Correction: the Citroën ë-C3's earlier "0-star" rating was for a different, India-spec car (Global NCAP), not the France-market ë-C3, which is actually unrated — fixed in 04 and index.md
• Full comparison table — new + secondhand, price, ~75%-incentive net price, safety, range, maintenance/yr, and total running cost/yr at 10,000km — see 10-budget-ev-shortlist-comparison.md
• Stacked bar chart, base price + 3yr maintenance per car, sorted by total — see 11-budget-shortlist-cost-bars.html
• Added VW ID.3 to Track B — new price (€34,990-48,100), secondhand (€17,790-39,990), 5-star Euro NCAP, fast charging — see 04-secondhand-market-survey.md and index.md
• Created a top-level "Buy a Car" hub page — links here as the current project, highlights 4 key sub-pages as cards; a home for future car-buying research beyond just this one — see ../Buy a Car/index.md
• Added Volkswagen ID.7 (Pro/Pro S) to the premium segment in the price-vs-range dataset and chart
• Rewrote index.md as a proper article: verdict table up top, price-vs-range chart reframed as the computed 8-car efficient frontier (drawn as a connected line, replacing the old unlabelled scatter), tight comparison tables for both tracks, methodology moved down under "The research"
• Added the first real secondhand BYD Dolphin Surf listing (SIPA Mérignac, 2026-08-12, €19,990, 100km, "Occasion récente") to 04 and to the used price-vs-mileage Pareto chart — priced at new, not below it, which corrects the earlier "too new for a secondhand market" note; it becomes the new frontier anchor point at the low-mileage end
• Filled the 06 data gap — real listings sourced for Dacia Spring, Nissan Leaf, Peugeot e-208, VW ID.3, BYD Atto 3, Renault Zoe, plus a range-midpoint for Fiat 500e. Result: the price-vs-mileage frontier collapses to just Dolphin Surf + Dacia Spring, exposing why range/mileage alone is the wrong frontier axis (see top priority above)
• Added reader-facing caveats before both frontier charts (03, 06, and index.md) flagging that Dacia Spring anchors both frontiers on price/range or price/mileage alone despite its 1★ safety rating — plus a new appendix, 12-weighted-quality-score-notes.md, mapping candidate dimensions and open questions for a real weighted quality score. Design notes only.
• Extended the appendix to a second, equally-broken axis: sticker price is the wrong X-axis on both frontiers — should be annualized cost of ownership (depreciation/yr + running costs/yr + risk-adjusted damage/repair), with a worked example (€60k car depreciating €2k/yr beats €30k car depreciating €3k/yr on true cost). Design notes only — both axes now flagged as the top priority above, still unsolved.
• First real pass at the price/cost axis — 13-five-year-cost-of-ownership.html: (entry − 5yr resale) + 5yr running costs, for 8 cars across both tracks, using real secondhand listings where available (Spring, Model 3, Model Y) and clearly-flagged estimates where not (Dolphin Surf, ID.7 — both too new for real 5yr data). Findings: secondhand Leaf beats every car here including the Spring; Model Y currently beats Model 3 (thin data, flagged provisional). Genuine progress, not a finished answer — see caveats in 12 and 13.
• Content architecture cleanup: trimmed narrative/callouts out of the standalone chart pages (03, 06, 11) that duplicated or belonged in index.md/the numbered docs — chart pages now carry a one-line standalone caption + the chart + data table + source links, with all interpretation living in index.md (03→index.md, 06→04-secondhand-market-survey.md, 11→10-budget-ev-shortlist-comparison.md). Also fixed two stale footer references left over from an earlier template. Reduces the duplicate-editing risk that caused the earlier redundant-callout cleanup.
• Restyled index.md's verdict section as HTML pick-cards (matching the "Buy a Car" hub's visual language: CSS custom-property theme tokens, light/dark aware) with inline SVG car-silhouette icons in place of the old plain markdown table.
• Swapped the SVG icons for real car photos — Wikimedia Commons, CC BY-SA 4.0, downloaded locally to assets/car-photos/ (not hotlinked) with in-card attribution to the photographer and a license link, satisfying the CC BY-SA attribution/share-alike terms. Nissan Leaf (2018 Tekna, photo by Vauxford) and Tesla Model 3 (2023, photo by Alexander Migl).

Still to do

• ⏭️ TOP PRIORITY — both frontier charts have the wrong axes, not just one. Quality axis still fully open (see 12) — concrete evidence: the used price-vs-mileage frontier collapses to just Dolphin Surf + Dacia Spring, with the Spring dominating on price alone despite 1★ safety. Price axis has a first pass now (13) but isn't rigorous yet: several exit values are estimated not sourced, running costs lean on brackets not full distributions, no damage/repair-risk line item, and no real per-model depreciation curve (13 uses single point-in-time listings, not a curve). Both still rank above the other open items below.
• Charts embed via iframe, not inline HTML/JS — known limitation, not fixed. Flowershow renders plain .md raw-HTML blocks via something like innerHTML, which browsers never execute <script> tags from — confirmed live: our inline <script> code survives in the published page source untouched, but the SVGs/tables it should populate stay empty. Flowershow does have a <CustomHtml html={...}/> component built for exactly this (their own example embeds a Tally form's script), but it requires MDX rendering (syntaxMode: mdx in frontmatter, or a .mdx file extension) and its docs don't confirm whether inline <script> logic (not just external script src=) executes through it — untested. Worth revisiting if iframe's mobile UX (fixed height, nested scroll) becomes a real problem.
• Resolve BYD Dolphin Surf's actual bonus écologique eligibility right now — depends on whether the specific car being bought is still China-built or already from the Hungary plant (ramping up from Q2 2026); the 10-table flags this as uncertain rather than resolving it
• Get a real Euro NCAP rating for the France-spec Citroën ë-C3 and a rating (once available) for Renault Twingo E-Tech — both currently unrated in this research
• Deeper used-market pass — individual listing samples (not aggregate/aggregator-summary bands, several still 1-listing anchors after this pass) and battery SOH figures where sellers disclose them, especially for the Nissan Leaf and Peugeot e-208 now that both are leading picks
• Confirm home charging access — the Leaf recommendation assumes overnight home charging; public-only charging would weaken the case
• Flesh out 08-why-buying-a-used-car-is-hard.md — more worked examples, a proper checklist; decide if/when it splits into its own piece outside this folder
• Weigh VW ID.3 properly against Model 3/e-208 in Track B — currently just added as a name with data, not yet compared in any depth
• Final recommendation and purchase decision — Track A (budget) narrowed to Leaf/e-208/Dolphin Surf pending the incentive question; Track B (family) still open, now three-way between Model 3, e-208, and ID.3

Files

• index.md — the article
• plan.md — this file
• 01-tax-incentives.md — bonus écologique, leasing social, malus, sources
• 02-model-tco-survey.md — models surveyed, running costs, depreciation trends, sources
• 03-price-range-sketch.html — interactive new-car price-vs-range chart
• 04-secondhand-market-survey.md — used-listing price bands, sources, Euro NCAP safety data
• 05-secondhand-price-bands.html — used price-band chart, Tesla by trim
• 06-secondhand-price-vs-mileage.html — used price-vs-mileage Pareto sketch
• 07-reading-a-real-listing.md — Model Y vs. Model 3 secondhand + a real listing priced against the research
• 08-why-buying-a-used-car-is-hard.md — stub piece on the general problem
• 09-ev-vs-ice-total-cost.md — is EV actually better value than petrol, purchase price + depreciation + running costs
• 10-budget-ev-shortlist-comparison.md — full table: new/secondhand, price, incentive-adjusted price, safety, range, running costs
• 11-budget-shortlist-cost-bars.html — stacked bar chart, base price + 3yr maintenance per car
• 12-weighted-quality-score-notes.md — appendix: design notes for a real price/quality frontier (both the quality axis and the price→annualized-cost axis)
• 13-five-year-cost-of-ownership.html — first real pass at the price/cost axis: (entry − 5yr resale) + 5yr running costs, 8 cars
• assets/leboncoin-model-y-listing.png — the listing screenshot used in 07
• data-ev-models.json / data-used-ev-price-bands.json — datasets behind the charts