Combination of independent clauses containing quantities

Solution 1:

Choice 1A seems correct, as the quantifier doesn't distribute itself individually across "vehicles, trains, aircraft". Logical operations treat the and and or cases differently, but in less-formal cases, and and or can treat them similarly.

For part 2, one can add "each of" to the sentence, "...officials inspect the more than 350 million travelers and 100 million each of vehicles, trains, and aircraft entering and exiting...", for precise but clumsy wording.

Comment: For more variations of wording (and re the problem with whether all those people and vehicles cross the subject bridge, or transit the 330 ports also mentioned), post in writers.stackexchange.

Solution 2:

1) It is more likely that interpretation A is correct. However, as Matt points out, the word vehicles can be vague, so better wording is needed here.

2)When the exact number and type of vehicles is known, you write ...x automobiles (I take it this is what is meant with the word vehicles), y trains and z aircraft entering...