It looks dangerous and honestly, they look very stupid.
Japanese law allows people to drive go karts on the street with no helmet.
More info.
https://www.expedia.com/things-to-do/go-kart-experience-on-tokyo-roads.a449458.activity-details?regionId=201&semcid=US.MULTILOB.GOOGLE.AT-c-EN.TSHOP&semdtl=a11345517908.b153620168546.r1.g1dsa-497511626357.i134296799554.d1270357722301.e1c.j19033254.k120636.f11t1.n1.l1g.h1b.m1&gclid=EAIaIQobChMInqXi7bTx4AIVC4GzCh1VzQMAEAAYASAAEgJAHvD_BwE