Federal Communications Commission
Notation 8491: The National Transportation Safety Board (NTSB) has reviewed the Federal Communications Commission (FCC) Notice of Proposed Rulemaking (NPRM), which was published at 78 Federal Register 21320 (April 10, 2013). The proposed rule would revise Part 15 of the Commission’s rules to permit operation of Unlicensed National Information Infrastructure (U-NII) devices within the 5 gigahertz (GHz) band. The 5 GHz band, specifically the frequency band between 5.850 and 5.925 GHz, serves as the platform for connected vehicle technologies essential to the advancement of transportation safety.
Connected vehicle technologies that rely on Dedicated Short Range Communications Service (DSRCS) systems are operating in the Intelligent Transportation Service (ITS) allocation on the 5 GHz band. Careful attention to interference risk is essential when considering permitting spectrum sharing, as proposed in this NPRM.
Since the mid-1990s, the NTSB has advocated intelligent vehicle technologies that rely on radar, vehicle-to-vehicle, or vehicle-to-infrastructure communications. Such technologies include collision warning and collision avoidance systems. The NTSB first addressed collision avoidance during its investigation of a 1995 multivehicle collision in Menifee, Arkansas,1 in which a commercial vehicle entered dense fog, slowed from 65 mph to between 35 and 40 mph, and was then struck from behind. Subsequent collisions occurred as vehicles drove into the wreckage. This accident, which involved eight loaded truck-tractor semitrailer combination units, resulted in five fatalities.
Even then, before today’s wirelessly connected world existed, the need to establish dedicated communication airwaves for technologies that could prevent such collisions was recognized. As a result of the Menifee accident, the NTSB issued Safety Recommendation H-95-46 to the FCC, which states as follows:
Expedite rulemaking action on the allocation of frequencies that would enhance the development possibilities of collision warning systems.
The FCC successfully allocated spectrum for collision avoidance systems, and Safety Recommendation H-95-46 was classified “Closed—Acceptable Action” in 1999. The NTSB is concerned that the proposed rulemaking for spectrum sharing may compromise this necessary spectrum allocation for collision avoidance systems, by increasing the potential for dangerous interference.
Since the closure of Safety Recommendation H-95-46, the NTSB has issued several additional safety recommendations concerning technologies that rely on wireless communication in the frequency band established by the FCC in response to Safety Recommendation H-95-46. These include recommendations to the National Highway Traffic Safety Administration (NHTSA) to research, establish performance standards for, and then require, advanced collision avoidance safety technologies on passenger and commercial vehicles. The NTSB issued the following recommendations as a result of investigations into accidents that killed or injured dozens of people.
To the National Highway Traffic Safety Administration:
Complete rulemaking on adaptive cruise control and collision warning system performance standards for new commercial vehicles. At a minimum, these standards should address obstacle detection distance, timing of alerts, and human factors guidelines, such as the mode and type of warning.
After promulgating performance standards for collision warning systems for commercial vehicles, require that all new commercial vehicles be equipped with a collision warning system.
2 (a) National Transportation Safety Board, Vehicle- and Infrastructure-based Technology for the Prevention of Rear-End Collisions, SIR-01/01 (Washington, DC: National Transportation Safety Board, 2001). (b) National Transportation Safety Board, Truck-Tractor Semitrailer Rear-End Collision into Passenger Vehicles on Interstate 44, Near Miami, Oklahoma, June 26, 2009, HAR-10/02 (Washington, DC: National Transportation Safety Board, 2010).
Complete rulemaking on adaptive cruise control and collision warning system performance standards for new passenger cars. At a minimum, these standards should address obstacle detection distance, timing of alerts, and human factors guidelines, such as the mode and type of warning.
Determine whether equipping commercial vehicles with collision warning systems with active braking and electronic stability control systems will reduce commercial vehicle accidents. If these technologies are determined to be effective in reducing accidents, require their use on commercial vehicles.
These recommendations to NHTSA have been repeatedly reiterated as a result of more recent investigations in which we have seen fatalities and injuries as a consequence of the absence of such accident-prevention technology.
These systems have advanced over the years since the NTSB began advocating their development, standardization, and inclusion in modern vehicles. The US Department of Transportation has sponsored voluntary standards, conducted cost-benefit analyses, and begun fleet operational testing. NHTSA analyses show that DSRCS-based connected vehicle technology could address approximately 80 percent of the crash scenarios involving non-impaired drivers.4 Given the progress that has been made by government and industry leaders in this area, such an outcome is a realistic possibility. The NTSB believes that all newly manufactured automobiles and commercial motor vehicles should be equipped with these crucial lifesaving technologies and has made “Mandate Motor Vehicle Collision Avoidance Technologies” a priority on our current Most Wanted List.
The implementation of this technological opportunity to improve transportation safety so significantly must not be compromised by issues associated with interference on the 5 GHz band. The NTSB is not opposed to spectrum sharing in principle, but the security of preestablished communication frequencies related to transportation safety must first be ensured. Spectrum sharing could put the frequencies at risk of dangerous interference, and much is still unknown about frequency interference when it comes to vast numbers of connected vehicles in motion. A single incident like the case of interference encountered by the Federal Aviation Administration (FAA) with its Doppler radar could stall progress and cause concern within the industry—or even result in accidents, once these systems are deployed.
The National Telecommunications and Information Administration (NTIA) is beginning its evaluation process to test the use of UNII devices on the 5 GHz band. The NTIA 5 GHz report, cited in the subject NPRM, identifies a number of risk elements associated with the likelihood of harmful interference from large numbers of U-NII devices and concludes that further analysis will be required to determine how the identified risk factors can be mitigated. Such analysis should be conducted before safety-sensitive frequencies are opened up to UNII devices. Yet, the need for such analysis will likely delay the widespread deployment of these much-needed safety systems.
The NTSB appreciates the opportunity to provide these comments. Given our long history of advocating for collision avoidance technologies, the NTSB is very concerned that the development of these technologies—potentially saving thousands of lives each year—would be put at risk. Consequently, we urge the FCC to ensure that potential delays to the development of the collision avoidance development are considered before UNII devices are allowed to operate in the 5 GHz band and that the key elements of the transportation safety systems that communicate on the same frequency are adequately and reliably protected.