with whom SAUFLEY, C.J., and CLIFFORD, J. join, concurring.
[¶ 25] I join in the Court’s opinion except on the question of the admission of the expert testimony of Albert Godfrey. God-frey applied the algebraic equation for a critical speed scuff analysis to a 131-foot scuff mark and a 42-foot skid mark left on the road surface by Irving’s car immediately before it left the road and entered a field. As noted by the Court, Godfrey’s decision to apply the formula to a scuff mark without any sign of crossover (crossover is exhibited when a rear tire scuff mark crosses over a tire scuff mark left by the corresponding front tire) and with evidence of braking was contrary to the expert opinion of the State’s other expert witness, Trooper James Wright. It was also contrary to the opinion provided by the defendant’s expert, Dr. Thomas Bohan, who testified that the formula should not be applied when there is evidence of braking.
[¶ 26] Serious questions were raised regarding the reliability of Godfrey’s expert opinion in part because of his application of the critical speed scuff analysis under these circumstances, but also because his testimony was internally contradictory and, at times, difficult to comprehend. For example, considerable attention was paid to the conflict between Godfrey’s pretrial report in which he wrote “that while the vehicle was traveling at a very high rate of speed, it probably was not traveling upwards of 100 miles an hour[,]”9 and his voir dire testimony in which he testified “I can see the vehicle traveling upwards of a hundred miles per hour.” In addition, Godfrey referred at different points of his testimony to 100 mph as representing the “minimum” speed and the “maximum” speed of Irving’s vehicle.
[¶ 27] The preceding problems were compounded by a more fundamental problem associated with the scientific basis for Godfrey’s opinion. He explained the algebraic formula that is employed in critical speed scuff analysis, which is derived from Newton’s laws of physics: “To calculate *212the speed, it is [3.86] times the square root of the radius of that scuff times the coefficient of friction plus or minus the super elevation of the roadway.” He also explained that the multiple of 3.86 used to determine the “[m]inimum speed of a yaw mark ... was calculated from years of experimentation in the development of that formula.” Godfrey offered no scientific basis, however, for his decision to reduce the 103 mph speed, derived from the formula, to 100 mph. He acknowledged that if a vehicle’s brakes are being applied, the critical speed scuff analysis will produce a speed that is higher than the actual speed. He testified:
Brakes can be applied without locking the wheels in a critical speed scuff and not negligibly change the — it will be slightly lower — or the speed will be slightly higher that it will give you. We know that at the end of it the wheel was locked up; therefore, I am being conservative by my hundred and three miles an hour, saying there in my third of a century plus experience, that that hundred and three is probably a little high; that brakes were starting to be applied somewhere during that scuff because the wheel did lock up at the end of it. Therefore, the hundred and three probably — it might be true, a hundred and three might actually be true there, but I’m being conservative saying there that I ought to reduce it down some due to the fact that at the end of it the wheel locked up. That’s why ... I am saying there upwards of a hundred miles an hour.
[¶ 28] Thus, after having testified to his belief that critical speed scuff analysis can be applied with accuracy to scuff marks where there is no evidence of crossover and there is evidence of braking, a position contrary to the State’s other expert witness and Irving’s expert witness, Godfrey acknowledged the need to deviate from the formula because of the evidence of braking. He offered neither a scientific basis for such deviation nor a formula for determining the deviation. The only basis for Godfrey’s deviation from a formula based upon established science was his “third of a century plus experience.”
[¶ 29] In State v. Boutilier, 426 A.2d 876, 879 (Me.1981), the standard for determining the admissibility of expert opinion testimony was described as follows:
When determining the admissibility of proffered expert opinion testimony in terms of its relevance and helpfulness to the jury, the presiding justice should evaluate whether what is claimed as “scientific” is really so, and in this regard one important (if not controlling) consideration is whether the matters involved have been generally accepted or conform to a generally accepted scientific theory.
[¶ 30] The divergence of Godfrey’s opinion from Trooper Wright’s and Dr. Bo-han’s opinions regarding the use of critical speed scuff analysis made it particularly important for the State to establish that Godfrey’s determination of speed was premised entirely, not just partially, on an accepted scientific theory. Because the State failed to meet this burden, Godfrey’s expert opinion was not shown to be reliable and should not have been admitted.
[¶ 31] Although I conclude that the trial court erred in admitting Godfrey’s testimony, I concur in the Court’s opinion because the error was harmless. “Error is harmless when it is highly probable that it did not affect the jury’s verdict.” State v. DeMass, 2000 ME 4, ¶ 17, 743 A.2d 233, 237. The State offered the expert opinion of Trooper Wright that Irving’s vehicle was traveling a minimum of 73 mph in the field after leaving a road that was posted as a 35 mph speed zone. In addition, the *213lay testimony and exhibits established, among other things, that even after Irving’s vehicle left the road and crossed a grassy field, it was traveling at a rate of speed sufficiently high for it to become airborne immediately before striking a tree. The strength of the State’s evidence, apart from Godfrey’s expert opinion, supports the conclusion that it is highly probable that Godfrey’s testimony did not affect the jury’s verdict.
. The report was not received in evidence; this excerpt from the report was stated on the record by the trial judge.