Puzzle

Road construction is sometimes quite puzzling, especially with large bridges, long tunnels, etc..
But this piece of asphalt should not give a reason for being puzzled. At the right hand side the road is a bit lower, and that road is going to have a new layer of asphalt replacing the old and cracking one.
Away from us, so to the top side of the picture, is a bridge, with a fix surface that can't be lowered.
The construction workers had removed the asphalt between the crossing and the road to the right last week, and this morning they filled the gap with asphalt.
But: they kept the new asphalt at the level of the right road, thus leaving a kind of sill or threshold.
Will they put a quite thin layer of asphalt on top of the new asphalt? Will that stick to the bottom layer, or will it be too thin? Why didn't they fill the gap properly this morning already, without the need to come a second time? I'm puzzled.