latlngs = [<?php for ($i=0;$i<count($latts);$i++){echo '['. $latts[$i] .', '. $longs[$i]     .']';if($i!=count($latts)-1){echo ',';}} ?>],
itinerary = L.polyline(latlngs, {color: 'red'});
itinerary.addEventListener('click dblclick', function(e) {
    console.log(e);
    var res = e.latlng; // that's nice but I'd like to be able to get e.speed, etc...
});
map.addLayer(itinerary);