Doucet's design comprises a stack of 3D-printed concrete benches, which weigh over one ton and attach to each other via steel rods. When the chunky seats are hit by a vehicle, they remain linked and skid along discs to form a barrier.
Rely, which was built at Times Square for this year's NYCxDesign festival, is intended as a "discreet" alternative for protecting pedestrianised areas from vehicle-ramming attacks carried out by terrorists, as well as car accidents.
"Traditional concrete barriers meant to provide safety from weaponised vehicles tend to be brutalist, intrusive and function as an ugly reminder that we are not safe in large congregations," Doucet told Dezeen.
"Rely adopts a different, humanist approach, offering alternate function as seating when not performing protective duties, and enhancing its surroundings with beauty rather than constant reminders of aggression."
Doucet is the latest designer to propose solutions to deter terrorists following a spate of attacks on pedestrians using vehicles, including one in Manhattan in 2017.
Italian architect Stefano Boeri proposed employing trees and bulky planters instead of intimidating military-style barricades, while UK engineering firm ATG Access designed the Surface Guard to protect fans at football grounds without "an unfriendly or menacing feel".
Doucet teamed up with UrbaStyle, a concrete street furniture manufacturer, to produce the Rely Bench.
Together, they worked to develop a system that 3D prints the benches with extrusion, a technique that dispenses material through a computer-controlled nozzle or an orifice. Extrusion is typically used with plastic filament and has never been applied to concrete before, according to Doucet.
"The manufacturing technique is novel as well," said the designer. "Each component is digitally extruded in a wholly digital manufacturing process, which has never before been applied to concrete."
The benches have a triangular profile, so that they can be easily stacked in "infinite" configurations, while the printing methods leaves striated markings on the surface.
This is Doucet's latest attempt to improve safety on roads, following a motorcycle helmet with built-in lights that flash red when the driver slows down or brakes.
Rely was built for the Times Square Design Lab initiative from 10-22 May to coincide with NYCxDesign 2019.