The device is constructed from mostly off-the-shelf materials. The straps, which are made from a fabric that secures crates on trailer trucks, are unfurled by the mechanism that inflates car airbags. By next year, the team plans to make SQUID strong enough to stop a 120mph, 5,000-pound truck. The device is now an obvious white disk, but because it spans a traffic lane, it's hard to avoid. The final version will blend into the street, explains the company's president, Martin Martinez, "but we don't want to tell bad guys what it's going to look like."