No opposite drive / Deceleration zone

Ordinary roadblock can slow down the cars, but it has no definite function of preventing retrograde. The roadblock we designed can avoid this problem; we conceived it as asymmetrical patterns. When you drive on the right way, the slope is gentle but your speed will be slow down; while you drive in reverse, the slope become steep, you will be slow down rapidly and feel strong shock, warming that you are in danger. So some accidents caused by driving in reverse can be avoided or decreased to some extent.