The Police Department has been planning a high-tech security network for Midtown Manhattan involving surveillance cameras, license plate readers and chemical sensors, although it was not clear whether it could have prevented the attempted car bombing in Times Square on Saturday night.

The network, patterned after one under development in Lower Manhattan, would eventually use public and private security cameras and license plate readers and would be able to record and track every vehicle moving between 34th and 59th Streets, river to river. But because neither the S.U.V. used in the attempt nor the license plate on it had been reported stolen, it would not have raised any immediate red flags.

Eventually, police officials have said, the networks would be able to notice whether a car was circling any area suspiciously. Because the security network is not yet in place in Midtown, it was not known whether the S.U.V. was driven directly to its target on Saturday night.

The network could have been triggered via its chemical, biological and radiological sensors, presuming that the material in the vehicle, which is not yet fully analyzed, was detectable.