State lawmakers on Wed­nesday announced a new proposal to curb truck terror attacks by compelling vehicle-rental workers to grill customers on their plans — and then report sketchy ­answers to authorities.

But many on the front lines were skeptical that terrorists would say anything damning. “If someone’s going to do something crazy, they’re not going to tell you,” said Chris Watson, 40, a manager at VTI Van Rentals in Brooklyn.

State Sen. Jeff Klein and his Independent Democratic Caucus released their “Vehicle Ramming Protection Act” a week after an ISIS sympathizer plowed a Home Depot rental truck into people on a bike path in lower Manhattan, killing eight.

The bill — which Klein plans to introduce in the next couple of weeks — requires the state Division of Homeland Security to create guidelines for rental companies to screen customers based on their responses to specific questions and “suspicious activity,” like repeatedly renting vans.

“Someone looks suspicious, someone pays in cash — these are sometimes just common-sense things that I think we should require companies to do in a uniform way to spot these telltale signs,” said Klein who represents parts of The Bronx and Westchester.

Van-rental and commercial trucking companies would also have to create “vehicle-ramming prevention plans,” which could sound alarms if a trucker suddenly veers off route — possibly signaling a carjacking.

“I think it’s not a bad start, albeit a nascent attempt, to start trying to address this issue,” said Jack Thomas Tomarchio, a Foreign Policy Research Institute senior fellow and ex-Department of Homeland Security official.