Some drivers in North Fort Worth on Friday were stopped at a police roadblock and directed into a parking lot where they were asked by federal contractors for samples of their breath, saliva and even blood. The request was part of a government research study aimed at determining the number of drunken or drug-impaired drivers.**UPDATE TO THE VIDEO ABOVE** Fort Worth police initially said they could not immediately find any record of their officers being involved in the roadblock, but on Tuesday police spokesman Sgt. Kelly Peel said that the department's Traffic Division coordinated with the NHTSA on the use of off-duty officers after the agency asked for help with the survey. "We are reviewing the actions of all police personnel involved to ensure that FWPD policies and procedures were followed," he said. "We apologize if any of our drivers and citizens were offended or inconvenienced by the NHTSA National Roadside Survey."