Showing LaneDepartureWarning from vPIC Without Inventing ADAS Grades

NHTSA vPIC often returns lane-assist catalog fields on DecodeVinValues-style payloads -- including LaneDepartureWarning and related lane-keep / lane-assist tokens when the pattern includes them. Those strings are useful on a free VIN decode card. The trap is turning a single sourced field into an IIHS-equivalent grade, "Lane Assist Package," or brochure ADAS suite that the catalog never asserted.

This post is about honest display: show LaneDepartureWarning when vPIC provides it, refuse ADAS-grade inventing, and allow a clean "not provided" state when the field is empty. Keep lane-departure catalog values separate from crash-test scores, BlindSpotMon, ForwardCollisionWarning, and OEM suite marketing names. A sourced token is still only a token: it does not prove the feature is present, calibrated, or undamaged on the listed vehicle. (Blind-spot honesty is a separate topic; here the focus is LaneDepartureWarning and close cousins.)

What LaneDepartureWarning is (and is not)

LaneDepartureWarning is a catalog attribute associated with the VIN decode. It answers a narrow question: which lane-departure warning token did the decode associate with this pattern?

It does not answer:

• Whether the vehicle earned an IIHS or NHTSA star rating for lane support
• Whether a dealer "Lane Assist Package," "Driver Assist," or OEM suite name is equipped
• Camera vs radar hardware, haptic vs audible alert, or steering-assist details you did not source
• Whether the feature works today, was optioned, or was deleted after manufacture
• A composite "ADAS completeness" score built from missing neighboring fields

Empty LaneDepartureWarning does not authorize a default "Standard" badge, and a positive token does not mean "full lane-keep suite verified." Do not fill gaps from Make/Model/Year folklore or a chart keyed only by model year.

Normalize empties, do not invent grades

Treat blank, "Not Applicable", "N/A", and similar tokens as missing. Keep a sourced string when present; do not rewrite it into "Lane Keep Assist Plus" or an IIHS-style grade.

const EMPTY = new Set([
  "",
  "not applicable",
  "n/a",
  "na",
  "null",
  "none",
  "unknown",
]);

export type LaneDepartureView = {
  value: string | null;
  source: "vpic" | "missing";
};

export function viewLaneDepartureWarning(fields: {
  LaneDepartureWarning?: string | null;
}): LaneDepartureView {
  const raw = (fields.LaneDepartureWarning ?? "").trim();
  if (!raw || EMPTY.has(raw.toLowerCase())) {
    return { value: null, source: "missing" };
  }
  return { value: raw, source: "vpic" };
}

export function laneDepartureLines(view: LaneDepartureView): string[] {
  if (view.source === "missing") {
    return [
      "Lane departure warning: not provided by vPIC for this VIN",
    ];
  }
  return [
    `Lane departure warning (vPIC): ${view.value}`,
    "Catalog token only -- not an ADAS grade or package claim",
  ];
}

The footnote matters. Buyers over-read a single lane field as a verified suite. Show the sourced token; if blank, say "not provided" -- no greyed "Standard" and no invented package name.

Forbidden upgrades

Product pressure often asks for:

1. Mapping any non-empty LaneDepartureWarning into "Lane Assist Package included"
2. Inventing IIHS / Euro NCAP / star-equivalent language from catalog lane fields
3. Bundling LaneDepartureWarning with BlindSpotMon or ForwardCollisionWarning into "Full ADAS"
4. Defaulting blank LaneDepartureWarning to "Standard" so mid-trim cars look complete
5. Renaming catalog tokens into OEM suite marketing names you did not source

Refuse those. If you show other ADAS catalog fields from separate sourced keys, show each on its own row. Never invent a package name inside the LaneDepartureWarning mapper.

export function assertNoLaneAdasInvent(moduleSource: string): void {
  const banned = [
    /lane assist package/i,
    /iihs/i,
    /5-star equivalent/i,
    /full adas/i,
    /driver assist suite/i,
    /euro ncap/i,
  ];
  for (const re of banned) {
    if (re.test(moduleSource)) {
      throw new Error(
        `LaneDepartureWarning module must not invent ADAS grades: ${re}`,
      );
    }
  }
}

export type CardRow = { label: string; value: string };

export function cardRows(fields: {
  LaneDepartureWarning?: string | null;
  BlindSpotMon?: string | null;
  ForwardCollisionWarning?: string | null;
}): CardRow[] {
  const view = viewLaneDepartureWarning(fields);
  const out: CardRow[] = [];
  if (view.source === "missing") {
    out.push({
      label: "Lane departure warning",
      value: "not provided",
    });
  } else {
    out.push({
      label: "Lane departure warning",
      value: String(view.value),
    });
  }

  const bsm = (fields.BlindSpotMon ?? "").trim();
  if (bsm && !EMPTY.has(bsm.toLowerCase())) {
    out.push({ label: "Blind spot monitoring (vPIC)", value: bsm });
  }
  const fcw = (fields.ForwardCollisionWarning ?? "").trim();
  if (fcw && !EMPTY.has(fcw.toLowerCase())) {
    out.push({ label: "Forward collision warning (vPIC)", value: fcw });
  }
  return out;
}

Keep neighboring ADAS fields on their own labeled rows. Never concatenate them into "Full Lane Assist Package."

UI copy that stays honest

Prefer:

• "Lane departure warning (vPIC): Standard"
• "Lane departure warning: not provided by vPIC for this VIN"
• A short footnote: catalog token, not an ADAS grade or package claim

Avoid:

• "IIHS Lane Support Good -- verified"
• "Full Driver Assist Suite included"
• Grey placeholders that look like real lane-assist data when the field was empty

Quick checks

import assert from "node:assert/strict";

assert.equal(viewLaneDepartureWarning({}).source, "missing");
assert.deepEqual(
  laneDepartureLines(viewLaneDepartureWarning({})),
  ["Lane departure warning: not provided by vPIC for this VIN"],
);

const std = viewLaneDepartureWarning({
  LaneDepartureWarning: "Standard",
});
assert.equal(std.value, "Standard");
assert.ok(
  laneDepartureLines(std).some((l) =>
    /not an ADAS grade or package/i.test(l),
  ),
);
assert.ok(
  !laneDepartureLines(std).some((l) =>
    /iihs|full adas|lane assist package/i.test(l),
  ),
);

const rows = cardRows({
  LaneDepartureWarning: "",
  BlindSpotMon: "Standard",
  ForwardCollisionWarning: "Standard",
});
assert.ok(
  rows.some(
    (r) =>
      r.label.includes("Lane departure") && r.value === "not provided",
  ),
);
assert.ok(rows.some((r) => r.label.includes("Blind spot")));
assert.ok(rows.some((r) => r.label.includes("Forward collision")));
assert.ok(!rows.some((r) => /full adas|iihs/i.test(r.value)));

Review rule: lane-departure modules must not contain ADAS-grade or package marketing phrases except in forbidding tests. Never upgrade a blank into "Standard."

Takeaway

LaneDepartureWarning is a catalog token. Display it with clear sourcing, allow "not provided," and never use it as a key into invented IIHS grades, OEM suite names, or "full ADAS" bundles. Your free VIN UI stays trustworthy when lane-departure data is either a real vPIC value with a modest footnote -- or absent -- and safety marketing lives somewhere else, clearly labeled, or not at all.

I maintain VIN Lookup, a free VIN decode based on NHTSA data.