The Road Safety Foundation said 458 road crashes in July killed 416 people and injured 629.
Its monthly assessment counted 57 women and 48 children among those killed.
The foundation recorded 159 motorcycle crashes, or 34.71 percent of all crashes, in which 138 people died.
It said pedestrian deaths numbered 106, while 51 drivers and assistants were killed.
National highways accounted for 169 crashes, followed by regional roads with 155, city roads with 66 and rural roads with 61.
Loss of control was listed in 164 crashes, head-on collisions in 123, pedestrian strikes in 108 and rear-end crashes in 54.
The foundation counted 711 vehicles involved, including 172 motorcycles, 131 three-wheelers and 124 buses.
It said 28.82 percent of crashes occurred in the morning and 19.43 percent at night.
Dhaka division had the highest reported total, with 133 crashes and 125 deaths; Barishal division had the lowest, with 28 crashes and 24 deaths.
In Dhaka city, the foundation recorded 34 crashes, 18 deaths and 47 injuries.
The foundation cited defective vehicles and roads, speeding, unskilled driving, long working hours, low-speed vehicles on highways, traffic-law violations and weak traffic management as key factors in its assessment.
It recommended reforms including restructuring the National Road Safety Council and transport agencies, removing expired vehicles, improving driver training and health care, and building service roads along highways.