route_condition_forecast

Per-segment weather and hazard forecasting along a planned route.

You have a route. The driver will reach segment N at time T. What weather and hazards will be there when she arrives — not now, not at the start, but at her actual time-of-arrival per segment?

route_condition_forecast projects current driving_weather conditions and fleet_hazard zones onto route segments using time-of-arrival weighting. The result is a RouteForecast answering "what will conditions be when she gets there?" segment by segment.

Pure Dart. No Flutter.

0.2.0 fixes a safety defect present through 0.1.5. A route whose segments carried unmeasured weather answered hasAnyHazard == false — i.e. it declared itself CLEAR — and that answer flowed into adaptive_reroute, which reported "Route is clear" with confidence: 1.0. Verdicts are now tri-state and the bool accessor is gone; if (forecast.hasAnyHazard) will not compile. Read the CHANGELOG before upgrading — the compile error is the fix.

What it gives you

• RouteSegmenter — splits a route into time-aware segments.
• RouteConditionForecaster — projects forecast conditions onto segments with ETA weighting; flags hazard intersections.
• RouteForecast — typed result with per-segment condition snapshots, hazard intersections, and a tri-state SafetyVerdict get hazard (hazardous / notHazardous / unknown), plus firstHazardEtaSeconds, firstUnassessedSegment, coversWholeRoute.
• ForecastProvider — pluggable; ships with CurrentConditionsForecastProvider (uses current weather as best estimate) for cases where no time-series forecast source is available.

Install

dependencies:
  route_condition_forecast: ^0.2.0

Use

import 'package:route_condition_forecast/route_condition_forecast.dart';

final forecaster = RouteConditionForecaster(
  forecastProvider: CurrentConditionsForecastProvider(currentWeather),
  hazardZones: myHazardZones,
);

final forecast = await forecaster.forecast(routeResult);

// TRI-STATE. `unknown` is not "clear": it means the route could not be
// assessed (an unmeasured segment, or a maneuver that carried no position and
// so was never forecast at all).
//
// Do NOT write `forecast.hazard == SafetyVerdict.hazardous ? warn() : allClear()`
// — that puts `unknown` back in the all-clear branch, which IS the defect.
switch (forecast.hazard) {
  case SafetyVerdict.hazardous:
    print('Hazard at ${forecast.firstHazardEtaSeconds} seconds in.');
  case SafetyVerdict.unknown:
    print('Route conditions unknown — the route could not be assessed.');
  case SafetyVerdict.notHazardous:
    print('Route assessed, no hazard found.');
}

for (final segment in forecast.segments) {
  print('Seg ${segment.index}: ${segment.condition.summary} '
        '(arrival in ${segment.etaSeconds}s)');
}

When to use this

When you have a planned route and need to know what conditions the driver will encounter as she progresses through it — not just current conditions at the starting point. Useful for:

• "Snow is coming in 30 minutes; will I be in the worst of it on the highway segment or the city segment?"
• "Hazard reported 5 km ahead; will I reach it before or after the road warms above freezing?"
• "Pre-trip risk summary: how many segments of the planned route have active hazard zones?"

If you only need current conditions at a single point, depend on driving_weather directly.

License

BSD-3-Clause. See LICENSE.