level sensors for good road evenness, ultrasonic measuring accuracy placed on tarmac spreading machine

accuracy alignment asphalt asphalting automatic automotive bitumen blacktopping bridge construction correcting equalization equates evenness flatting fresh gasket good grade gravel heat height hot industrial industry layer laying level machine machinery measure measured measurement measuring modern multiplex non-contact noncontact pavement paving pebble positioning realign road roadwork roller sensing sensor sensors site slope special spreader spreading steamroller tar tarmac ultrasonic value workplace