    if (pieCanvas) {
                    const ctx = pieCanvas.getContext('2d');
                    new Chart(ctx, {
                        type: 'pie',
                        data: {
                            labels: transportStats.map(stat => stat.transportMode),
                            datasets: [{
                                data: transportStats.map(stat => convertDistance(stat.totalDistanceKm)),
                                backgroundColor: transportStats.map(stat => transportColors[sta