Dry bulk tanks: Question Dry bulk tanks: Answers Cannot be driven on interstates. Take special care to be driven. Are usually not allowed to cross railroad tracks. Explanation Dry bulk tanks require special care to be driven, both because they have high centers of gravity and because the weight of the load can shift in transit. This questions appears in the following tests: Idaho Class B Knowledge Test Iowa Class A Knowledge Test Iowa Class A Knowledge Test Missouri Class A Knowledge Test Nebraska Class B Knowledge Test