Isibane sebhuleki ephezulu siqhele ukufakwa kwinxalenye ephezulu ngasemva kwesithuthi, ukuze imoto eqhuba ngasemva kube lula ukuyibona ibhuleki yangaphambili yesithuthi, ukuthintela ingozi yangasemva. Ngenxa yokuba imoto ngokubanzi inezibane ezimbini zebhuleki ezifakwe ekupheleni kwemoto, esinye ngasekhohlo nesinye ngasekunene, ngoko ke isibane sebhuleki ephezulu sikwabizwa ngokuba sisibane sebhuleki sesithathu, isibane sebhuleki ephezulu, isibane sebhuleki sesithathu. Isibane sebhuleki ephezulu sisetyenziselwa ukulumkisa imoto engasemva, ukuze kuthintelwe ukungqubana kwangasemva.
Izithuthi ezingenazo izibane eziziibhuleki eziphezulu, ingakumbi iimoto ezincinci ezine-chassis ephantsi xa zibhuleki ngenxa yendawo ephantsi yesibane sebhuleki yangasemva, zihlala zingakhanyi ngokwaneleyo, ezi zithuthi zilandelayo, ingakumbi abaqhubi beelori, iibhasi kunye neebhasi ezine-chassis ephezulu ngamanye amaxesha kunzima ukuzibona ngokucacileyo. Ke ngoko, ingozi efihlakeleyo yokungqubana ngasemva inkulu kakhulu. [1]
Iziphumo ezininzi zophando zibonisa ukuba ukukhanya kwebhuleki ephezulu kunokuthintela kwaye kunciphise ukwenzeka kokungqubana kwangasemva. Ke ngoko, izibane zebhuleki ephezulu zisetyenziswa kakhulu kumazwe amaninzi aphuhlileyo. Umzekelo, eMelika, ngokwemigaqo, zonke iimoto ezisandula ukuthengiswa kufuneka zixhotyiswe ngezibane zebhuleki ephezulu ukusukela ngo-1986. Zonke iilori ezikhaphukhaphu ezithengisiweyo ukusukela ngo-1994 kufuneka nazo zibe nezibane zebhuleki ephezulu.
