Bumper ifite imikorere yo kurinda umutekano, imitako no kunoza ibimenyetso bya Aerodynamic byimodoka. Duhereye ku mutekano, imodoka irashobora gukina uruhare rwa buffer mugihe impanuka yihuta yo kugongana, kurinda umubiri wimodoka imbere kandi yinyuma; Mugihe habaye impanuka hamwe nabanyamaguru bishobora kugira uruhare runaka mukurinda abanyamaguru. Duhereye kubigaragara, ni ibyuma kandi bihinduka igice cyingenzi cyo kugaragara mumodoka. Mugihe kimwe, bumperi yimodoka nayo ifite ingaruka zimwe na kimwe cya aerodynamic.
Muri icyo gihe, kugirango bagabanye ibyangiritse kubayifite impanuka kuruhande, ubusanzwe bihambiwe nimiryango kugirango yongere imbaraga zo kurwanya imiryango. Ubu buryo ni ingirakamaro, yoroshye, ntoya, ntoya kumiterere yumubiri, yakoreshejwe cyane. Nko mu 1993 Shenzhen Imurikagurisha mpuzamahanga ry'imodoka, umuryango wimodoka wafunguwe kugirango ushireho amenyo kubari bateraniye aho kubona, kwerekana imikorere myiza yumutekano.
Kwishyiriraho urugi rumper kiri muri buri rugi rwisahani yumuryango utambitse cyangwa oblique imbaraga zimodoka zigenda hejuru, kugirango imodoka yimodoka izengurutse urutoki, kugirango imodoka yimodoka izenguruke, kugirango imodoka yicyuma ifite ahantu ntarengwa. Birumvikana ko kwishyiriraho urugi rurengera urugi bizatangira ibiciro bimwe byabakora imodoka, ariko kubatwara imodoka, umutekano no kumva umutekano bizongera byinshi.
