▁Por it . ▁ ▁In ▁the ▁early ▁ 1 9 6 0 s , ▁Adam ▁Op el ▁AG ▁chose ▁D uden hof en ▁as ▁the ▁location ▁for ▁their ▁test ▁centre , ▁which ▁came ▁into ▁service ▁in ▁ 1 9 6 6 . ▁In ▁the ▁middle ▁of ▁a ▁ 4 . 8   km - long ▁high - speed ▁loop ▁track ▁are ▁found ▁a ▁crash - test ▁facility ▁and ▁a ▁ 6 . 7   km - long ▁test ▁track ▁with ▁all ▁conce iv able ▁road ▁types ▁for ▁long term ▁tests . ▁ ▁Begin ning ▁in ▁the ▁ 1 9 6 0 s , ▁Rod g au ▁opened ▁up ▁six ▁major ▁industrial ▁par ks ▁with ▁a ▁combined ▁area ▁of ▁ 2 1 9   ha ▁in ▁which ▁settled ▁mainly ▁service ▁business es ▁such ▁as ▁the ▁IBM ▁product ▁distribution ▁centre ▁( until ▁ 2 0 0 5 , ▁there after ▁Mann - M ob ilia ▁log istics ▁centre ), ▁the ▁firm ▁Atlas ▁Rhein ▁Main , ▁the ▁F EG RO ▁wh oles ale ▁market , ▁ME WA ▁Text il service , ▁G E OD IS , ▁Pe psi - Col a ▁Deutschland , ▁Per kin El mer ▁Life ▁and ▁Anal yt ical ▁Sciences ▁and ▁a ▁D HL ▁postal ▁fre ight ▁centre . ▁All ▁together , ▁in ▁mid - 2 0 0 5 , ▁there ▁were ▁reported ▁to ▁be ▁ 3 , 8 7 1 ▁business es ▁in ▁Rod g au , ▁among ▁them ▁ 2 3 ▁super mark ets ▁from ▁the ▁best ▁known ▁ch ains ▁and