Pavement flatness instrument

The utility model discloses a road surface flatness instrument, which comprises a rack, a front rotating wheel set, a rear rotating wheel set, a measuring wheel set, a traction rod and a controller, the front rotating wheel set and the rear rotating wheel set are respectively connected with the front end and the rear end of the rack, one end of the rack is further connected with a cleaning mechanism for cleaning dust, and the cleaning mechanism is located in front of the front rotating wheel set. The cleaning mechanism comprises a cleaning brush, and the overall length of the cleaning brush is larger than the width of the rack. According to the road surface flatness instrument provided by the utility model, the cleaning mechanism for cleaning pebbles, soil and the like on the road surface is arranged in front of the front rotating wheel set, and the road surface can become clean through the cleaning mechanism, so that the impact of obstacles such as the pebbles, the soil and the like on the testing wheel and