"Connecticut State Police What is your emergency?"
"I-95 Northbound from Exit 9. Vehicle nearly hit the center divider. Still failing to maintain his lane. His speed has dropped to 35 (normal is 70+ at night). Vehicle description is as follows: blah blah. New York tag. Vehicle now in the right lane approaching exit 10."
"Thank you. (click)"
"She hung up on me!"
Part of the problem might be A) you didn't identify why this was important info, or B) didn't ID yourself.
2 ways I get around the 911 problem: "This is MDINANA, I'm an off-duty EMT..." which ususally works well when it comes to patching me through to the correct department quickly. Additionally, I've been known to just call 411 and ask for the dispatch center for the local agency- they don't ask nearly as many questions. Like others have said, the 7-digit number is often less busy than 911.