fleet_hazard 0.2.0

Fleet telemetry hazard model and geographic clustering for driver-assisting navigation. Road condition reports, hazard zones, and a pure Dart aggregation algorithm with pluggable providers. No Flutter [...]

fleet_hazard

Fleet telemetry hazard model and geographic clustering for driver-assisting navigation.

When to use this package

Use fleet_hazard when you need to turn individual snowy or icy vehicle reports into clustered, map-ready hazard zones.

Features

• FleetReport model with road condition, timestamp, confidence, and position.
• HazardZone cluster model with severity, vehicle count, and average confidence.
• HazardAggregator pure-Dart clustering algorithm for snowy and icy reports.
• FleetProvider abstract interface so apps can swap simulated, local, or remote telemetry backends.
• Pure Dart package with no Flutter dependency.

Install

dependencies:
  fleet_hazard: ^0.1.1

Quick Start

import 'package:fleet_hazard/fleet_hazard.dart';
import 'package:latlong2/latlong.dart';

final reports = [
  FleetReport(
    vehicleId: 'V-001',
    position: const LatLng(35.050, 137.250),
    timestamp: DateTime.now(),
    condition: RoadCondition.snowy,
  ),
  FleetReport(
    vehicleId: 'V-002',
    position: const LatLng(35.052, 137.252),
    timestamp: DateTime.now(),
    condition: RoadCondition.icy,
  ),
];

final zones = HazardAggregator.aggregate(reports);

for (final zone in zones) {
  print('${zone.severity.name}: ${zone.vehicleCount} vehicles');
}

Integration Pattern

fleet_hazard usually lives between a telemetry stream and a map overlay. Collect reports from your provider, aggregate them into zones, then render the zone summaries in whatever map widget or overlay layer your app uses.

import 'dart:async';

import 'package:fleet_hazard/fleet_hazard.dart';
import 'package:flutter/material.dart';

class HazardSummaryList extends StatefulWidget {
  const HazardSummaryList({
    super.key,
    required this.provider,
  });

  final FleetProvider provider;

  @override
  State<HazardSummaryList> createState() => _HazardSummaryListState();
}

class _HazardSummaryListState extends State<HazardSummaryList> {
  final reports = <FleetReport>[];
  StreamSubscription<FleetReport>? subscription;

  @override
  void initState() {
    super.initState();
    subscription = widget.provider.reports.listen((report) {
      setState(() {
        reports.add(report);
      });
    });
    widget.provider.startListening();
  }

  @override
  void dispose() {
    subscription?.cancel();
    widget.provider.stopListening();
    widget.provider.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final zones = HazardAggregator.aggregate(reports);

    return ListView(
      shrinkWrap: true,
      children: [
        for (final zone in zones)
          ListTile(
            title: Text('${zone.severity.name} zone'),
            subtitle: Text(
              '${zone.vehicleCount} vehicles • '
              '${zone.radiusMeters.toStringAsFixed(0)}m radius',
            ),
          ),
      ],
    );
  }
}

In a full navigation UI, this same zones list is what you would pass to a map overlay layer so the driver sees clustered snowy and icy segments, not raw per- vehicle noise.

Implement a provider

class MyFleetProvider implements FleetProvider {
  @override
  Stream<FleetReport> get reports => _controller.stream;

  @override
  Future<void> startListening() async {
    // Connect to your telemetry source
  }

  @override
  Future<void> stopListening() async {
    // Stop updates
  }

  @override
  void dispose() {
    // Release resources
  }
}

API Overview

Type	Purpose
FleetReport	Individual vehicle report carrying position, road condition, confidence, and timestamp.
HazardZone	Clustered geographic hazard summary with severity and confidence rollups.
HazardAggregator	Pure Dart clustering algorithm that converts reports into hazard zones.
FleetProvider	Stream-based interface for simulated, local, or remote fleet telemetry sources.
RoadCondition	Canonical hazard labels such as dry, snowy, and icy.

See Also

• kalman_dr — Dead reckoning through GPS loss (tunnels, urban canyons)
• routing_engine — Engine-agnostic routing (OSRM + Valhalla)
• driving_weather — Weather condition model for driving (snow, ice, visibility)
• driving_consent — Privacy consent with Jidoka semantics (UNKNOWN = DENIED)
• driving_conditions — Pure Dart computation models for road surface, visibility, and safety score simulation
• navigation_safety — Flutter navigation safety state machine and safety overlay
• map_viewport_bloc — Flutter viewport and layer composition state machine
• routing_bloc — Flutter route lifecycle state machine and progress UI
• offline_tiles — Flutter offline tile manager with MBTiles fallback

Part of SNGNav

fleet_hazard is one of the 10 packages in SNGNav, an offline-first, driver-assisting navigation reference product for embedded Linux.

License

BSD-3-Clause — see LICENSE.