Most longtime NMA members understand the weaknesses of using radar to measure vehicle speeds. However, less experienced drivers and even the courts regard radar as foolproof. Nothing could be further from the truth, and we have fresh evidence that further erodes radar’s patina of infallibility.
A member of the NMA Board recently attended a meeting of the American Academy of Forensic Sciences and was kind enough to forward us this description of one of the research presentations titled “Testing of Police Radar”. The research was conducted by two professional engineers, one of whom previously worked for one of the radar manufacturers.
The gist of the presentation is that, despite 30 years of technological innovations, radar still suffers from the same reliability and performance issues that have made it unacceptable as evidence in a court of law. The researchers state that radar cannot meet the requirements of the Daubert test, which is a set of standards trial judges use to determine whether or not expert testimony is based on valid scientific reasoning and methodology:
The reality of police radar is that it fails when subjected to the Daubert test. In this regard, police radar operation should be repeatable—this research demonstrates that it is not a repeatable technique and is, in fact, subject to operator interpretation when multiple targets are present.
The researchers tested several radar unit brands and units. With only one target, the units were pretty consistent in their speed measurements. However with multiple targets, there was no guarantee as to which vehicle’s speed was displayed. They observe that “the radar units can well read different speeds … the decision to issue a citation is highly dependent upon the operator, relative to the instrument.” This refers to one of radar’s biggest downfalls: it can’t distinguish one vehicle from another.
The researchers further explain that radar can pick out either the strongest signal or the fastest signal, depending on road conditions and the mix of vehicles on the road. It cannot, however, pick out the speed of the nearest vehicle. They point out that radar “gun sights” intended to aid target acquisition are useless. They also note that one radar manufacturer allows the officer to black out the displayed speed of the police vehicle in moving mode to conceal from the motorist that the officer was exceeding the speed limit.
Even though the researchers come from a technical/scientific background, they have the presence of mind to point out that radar speed enforcement encourages policing for profit. The NMA has been making this argument for years, but we have seen few other observers make the same connection between shoddy speed enforcement and revenue generation. The researchers further warn that using unreliable radar readings as an excuse to conduct a traffic stop and execute a questionable vehicle search raises Fourth Amendment questions:
But some jurisdictions use strict traffic enforcement as the basis of presumptive traffic stops—they will issue a warning for the traffic violation and instead are looking for a reason to search a vehicle for contraband.
Can anyone say civil forfeiture?
Overall, the study further supports the conclusion that radar speed measurement is unreliable, easily misused and often abused for revenue purposes. In the NMA’s “Fight That Ticket!” e-book, we show you how to use the many kinds of radar error to undermine the officer’s scripted testimony. When you prove to the court that what the officer has testified to is physically impossible or technically violates proper radar procedures, the prosecution’s case will be seriously compromised.