The opinion
Dissenting Opinion by
Mr. Justice Musmanno:
If there is one proposition in American law which is more firmly established than any other, one which is regarded almost with reverence since it involves the most precious possession of any citizen—his liberty and his good name—it is that no person may be convicted of crime unless the evidence establishes his guilt beyond a reasonable doubt. Reasonable doubt has been defined in a hundred different manners. One statement sums it up as follows: “Reasonable doubt is neither excessively timid nor excessively bold. It is not to be gauged by the actions of the man who would hesitate to cross a bridge resting on concrete piers and sus *297 pended by indestructible steel; nor by the actions of the man who would cross a bridge against fifty angels warning him that the piers had crumbled and the spans had fallen. Reasonable doubt is the doubt of a reasonable man. When the reason, like a bird flying over the sea, looks in vain for a substantial object on which to rest and fold its wings of perplexity, it can be said that the mind is in a state of reasonable doubt.” Commonwealth v. Clinton, 391 Pa. 212, 219 .
I cannot read the record in this case and say that the doubt which the evidence produces ever found a solid rock upon which to rest, assured that justice had been done and that the accused was convicted in accordance with the standards of American proof, engraved in the bronze of undeviating fairness and propriety.
This case involves the use of radar on the highway to record the speed of passing automobiles. No one can possibly laud the purpose of traffic radar more than I. To the extent that it reduces the appalling carnage occurring on the highways of the nation every day, by removing from the thoroughfares the reckless speeder, it is more than worth its weight in the gold of the lives it saves. Where the radar instrument is one that has been scientifically tested and proved to be mechanically reliable, and where it is scientifically applied so as to record the speed of a single automobile, there can be no question that the meter reading is á dependable one, and the conviction of the accused person, if the meter shows that the car was exceeding the speed limit, is not only warranted and justified, but imperative.
There can be no question also that the mere fact that motorists know that the radar’s eye is on them and that, like an unerring bloodhound, it will catch those who violate the speeding laws, serves to hold elevated the toe which might otherwise press the ac *298 celerator down to breakneck speed and possible bodycrnsbing collision. All that mast be taken for granted. Where a single automobile moves through the radar beam, the speed which is registered on the dial can only refer to one automobile because there is only one recording, and the officer manipulating the instrument sees who it is that is producing the recording.
In the case before us, however, there were five motor vehicles within the radar beam. Which one offended against the speed laws of the Commonwealth? Which one caused the radar needle to register 60 miles per hour? The Commonwealth says that it was the vehicle being driven by the defendant W. L. Bartley. The defendant denies he was the guilty driver.
We must understand that the radar instrument here under discussion does not, unlike military radar, show moving objects. It produces only one instantaneous, lightning flash result, a figure which speaks of miles p>er hour. In the field of identification the instrument is deaf, dumb and blind. Identification must be left to a human being and where a human being stands, there stands inevitably at his side, the possibility of human error. That possibility is minimal where only one car is involved, but where two cars enter into the pattern of moving events, doubt, raises its disturbing head.
Robert L. Bomboy, testifying for the Commonwealth as an expert in the use of radar, Avas asked by defendant’s counsel: “If they [the police officers] are observing the car in the lane, that’s in the right lane because it’s the first one to hit the beam and after the two cars go through, frankly, they don’t know which one has exceeded the speed limit, do they?” (Emphasis supplied)
The expert replied: “That’s right. . . .”
Bomboy also testified that where there are two vehicles within the registering .beam the radar picks up *299 “the largest moving object.” But when he was asked -if it always picked up the “largest object,” he replied: “Not necessarily.”' The following then occurred: “Q. I don’t understand that. A. All right, sir. Q. Wherein is- the difference? What do you mean by a better reflection? A. By the quantity'of energy received by the radar from, the moving target. Q. Wouldn’t you get a better reading on a larger target than a smaller one? A. Not if the car were going at a high rate of speed because when the car goes at a high rate of speed the Doppler frequency is higher and the present emphasis networks in" the radar takes over.”
All this, of course, raises a doubt of its own.
Defense counsel put more questions concerning two moving vehicles and then, asked which-one would register on the meter. The expert replied: “The car going at the highest rate of speed provided you get the best target return from it.” Does not -the proviso here— “provided you get the best target return from it”—eat up the main premise? Who and what determines what is the best'target return?
It appears that size, speed and proximity are all vital factors in- determining which vehicle is being clocked as to speed, but it has not been expertly decided which factor dominates over the other two when they vie for appearance on the dial. It is said that if two cars are at. the moment of recording running abreast, the nearer one to the radar instrument will register even though the one farther away is actually traveling at a higher rate of'speed."
But the doubt which is generated when only two cars, are involved becomes a complete rout, so far as technical accuracy - is concerned,- when three, four or five vehicles are within the radar beam simultaneously.
Up until this time we have said nothing about visibility, but it must now be stated that the recording in this case-was made at. night'in total darkness. There *300 were two police officers in the radar car, Chylak, who held the radar meter, and Rogers, who looked out into the road. Since more than one vehicle was on the highway at this point, as I have already stated, how did Rogers know which car it was that his partner noted in the radar dial as traveling 60 miles per hour? Rogers explained at the trial that he knew the exact spot where Chylak clicked the speed and that he saw the defendant’s car at that spot. It was an intriguing theory, but under cross-examination it was less than convincing: “Q. You said it was the first vehicle? A. You might say I knew because we have almost a given spot where the radar picks the vehicle up and you can just tell when the vehicle hits that given spot. . . . Q. I don’t follow you. This is midnight. This is late at night. It is pitch dark without headlights on these cars? A. Yes, sir. Q. You tell me how you can identify or point to a specific spot on this road anywhere along there and say positively that at that point a vehicle crosses? A. Well, if you direct your eyes back at one given place long enough, you can more or less tell it is a given spot. Q.. That’s the way you did it? A. That’s the way I did it.” (Emphasis supplied)
To say that one can pick out an exact spot in Stygian darkness and tell which car, out of a number of cars, passed that spot at a given instant, tips the scales of incredulity to the point where reasonable doubt dominates the entire face of acceptable evidence. Moreover, Rogers’ evidence was based on an assumption, which in itself is the antithesis of certainty. He was asked: “You just assume he said—when he said, ‘Sixty.’ You assume the first car was the car that went through that beam?” He replied: “That’s right, sir.”
I respectfully assert that this Court is doing the cause of effective radar surveillance a disservice by affirming a conviction which is founded in darkness, immersed in doubt, and wrapped in assumptions.
*301 What should be done is to build faith in radar where it is properly applied because, as I have said, it aims at saving human life. But it must not be used as an engine for trapping innocent motorists. I do not doubt that in time the radar system of checking automobile speed will develop to the point that even with multiple cars in the scene, the instrument will perfectly point out the motorist offender. It has not yet reached that stage of perfection and its meritorious record, to the extent of its capabilities, should not be marred by attributing to its mechanical virtues which it does not possess, thereby weakening the faith of the motoring public in its efficacy generally.
For these reasons I dissent.