A is an article. Articles accompany nouns, not verbs. Thus, an "a" article is perfectly possible in situations (that crop up from time to time in questions here) where there is a singular/plural discrepancy between the subject and the predicate that contains a noun (e.g., "Our problem was the widespread views on this subject"). For a situation of "n. pl. + are + n. sg.", a real-world usage example would be:
The methane detections were a big surprise. (source)
"Were" is governed by the plural of "detections". All of those multiple things were one single big surprise. Hence "a".
Things that were a hassle should be shared. (source)
Same logic. We have "were" because the word "things" is plural. But all of them are "a hassle".
In the case of your sentence, there is no such discrepancy. There is only one noun that has to be taken into account. It's the noun phrase "a wide range of car types." The main word here is "range". Thus, you must bring the verb in agreement with the word "range."
So it should be, "There is a wide range of car types."
It's not the article that is determined by a verb. Both the article and the verb are determined by a noun. The verb would be determined by the subject of the sentence. However, the predicate "was/were + noun phrase" could have a noun in any state of countability or multiple-ness (it's not a word, but you know what I mean).
Thus, yes, "a" can come after "are". It's just not determined by "are."