Bumpers vane mabasa ekudzivirira kuchengetedza, kushongedza kwemotokari, uye kuvandudzwa kweiyo aerodynamic maitiro emota. Kubva pane imwe nzvimbo yekuchengetedza maonero, apo tsaona yakadzika-yakadzika yekukwereta inoitika, mota inogona kuridza chinhu chinodzikisira kuchengetedza kumberi uye kumashure miviri yemotokari; Inogona kutamba imwe nhaka mukudzivirira vanofamba netsoka muchiitiko chetsaona nevanofamba netsoka. Panyaya yekutaridzika, inoshongedza uye yave chikamu chakakosha kurongedza kutaridzika kwemotokari; Panguva imwecheteyo, iyo mota bundu zvakare ine imwe yeiyo aerodynamic.
Panguva imwecheteyo, kuitira kuti uderedze kukuvara kune vagari vemota mune chiitiko chekushambadzira tsaona, gonhi rinowanzoiswa pamota kuti isimbise simba rekukanganisa kwemusuwo wemota. Iyi nzira inoshanda, yakapusa, uye ine zvishoma shanduko kune chimiro chemuviri, uye chakashandiswa zvakanyanya. Kuisirwa kwemusuwo bumper ndiko kuisa mwero wakakwira-simba rakakwira , kuumba "madziro emhangura", kuitira kuti vagari vemota vane nzvimbo yakakwirira yekuchengetedza. Ehezve, kuisa rudzi urwu rwemusuwo bumper hakuzowedzera kuwedzera mamwe emitengo kune vagadziri vemotokari, asi vagari vemota, kuchengetedzeka uye pfungwa yekuchengetedza vanowedzera zvakawanda.