                                NOT FOR PUBLICATION WITHOUT THE
                               APPROVAL OF THE APPELLATE DIVISION
        This opinion shall not "constitute precedent or be binding upon any court." Although it is posted on the
     internet, this opinion is binding only on the parties in the case and its use in other cases is limited. R. 1:36-3.




                                                         SUPERIOR COURT OF NEW JERSEY
                                                         APPELLATE DIVISION
                                                         DOCKET NO. A-5486-16T2

STATE OF NEW JERSEY,

          Plaintiff-Respondent,

v.

RICHARD CARRERA,

     Defendant-Appellant.
_____________________________

                    Argued September 21, 2018 – Decided August 26, 2019

                    Before Judges O'Connor and DeAlmeida.

                    On appeal from the Superior Court of New Jersey, Law
                    Division, Essex County, Indictment No. 17-04-0908.

                    Stefan Van Jura, Deputy Public Defender, argued the
                    cause for appellant (Joseph E. Krakora, Public
                    Defender, attorney; Stefan Van Jura, of counsel and on
                    the brief).

                    Kayla     Elizabeth   Rowe,      Acting       Assistant
                    Prosecutor/Special Deputy Attorney General, argued
                    the cause for respondent (Theodore N. Stephens II,
                    Acting Essex County Prosecutor, attorney; Kayla
                    Elizabeth Rowe, of counsel and on the brief).
PER CURIAM

      Defendant Richard Carrera appeals from a December 9, 2016 order of the

Law Division denying his motion to preclude the anticipated testimony of an

expert witness who used historical cell site data analysis to opine defendant's

cell phone was used in the general area of a homicide at the approximate time

of the crime. After the trial court denied the motion, defendant entered a guilty

plea to manslaughter and a weapons offense, reserving the right to challenge the

court's decision. We affirm in part, reverse in part, and remand for further

proceedings.

                                       I.

      This appeal arises from the February 8, 2014 shooting death of Reylin

Torres in a car on a Newark street. The details of the shooting are not relevant

to the issues before the court. A grand jury indicted defendant and co-defendant

Mark Hoskins for the shooting, charging them with: first-degree conspiracy to

commit murder, N.J.S.A. 2C:5-2 and N.J.S.A. 2C:11-3(a)(1); first-degree

murder, N.J.S.A. 2C:11-3(a)(1); second-degree unlawful possession of a

weapon, N.J.S.A. 2C:39-5(b); second-degree possession of a weapon for an

unlawful purpose, N.J.S.A. 2C:39-4(a); second-degree conspiracy to commit

robbery, N.J.S.A. 2C:5-2(a)(1) and N.J.S.A. 2C:15-1(a)(1); first-degree robbery,


                                                                         A-5486-16T2
                                       2
N.J.S.A. 2C:15-1(a)(1); first-degree felony murder, N.J.S.A. 2C:11-3(a)(3); and

second-degree certain persons not to have weapons, N.J.S.A. 2C:39-7(b).

Defendant entered a plea of not guilty.

      During discovery, the State notified defendant of its intention to call FBI

Special Agent John Hauger, a member of the FBI's Cellular Analysis Survey

Team (CAST), as an expert in historical cell site data analysis. Hauger was

prepared to offer the opinion that, based on his analysis of historical cell site

data, cell phones belonging to defendant and Hoskins exchanged transmissions

in the general area of the crime scene at about the time of the shooting.

      Defendant moved pursuant to N.J.R.E. 104 to preclude Hauger's

testimony. Although he did not object to Hauger's qualifications as an expert or

claim that the proposed testimony was within the ken of the average juror,

defendant argued the process Hauger used to reach his opinion is not a generally

accepted method in the scientific community, rendering his opinion and exhibits

inadmissible.   Defendant also challenged the admission of the illustrative

exhibits the expert created to assist the jury to understand his opinion.

      The following facts are derived from the record of the hearing on

defendant's motion, at which Hauger and Sprint radio frequency engineer

Michael Zahra, who was qualified at the hearing as an expert in


                                                                            A-5486-16T2
                                          3
telecommunications, and cell tower and cell phone operations, testified.

Historical cell site data analysis relies on the fact that a cell phone uses radio

frequencies to connect to nearby cell phone towers. A typical cell tower has

three 120 degree sectors, covering the full 360 degrees surrounding the tower

with antennae tilted downward for the purpose of providing blanket connectivity

near the tower. The area covered by a tower is not a perfect circle and the

coverage areas of nearby towers may overlap, particularly in urban areas.

      From the moment a cell phone is turned on it constantly scans the radio

frequency environment for the strongest signal from a cell tower. The cell

phone's scanning takes place whether or not the cell phone is moving. When a

cell phone "sees" a tower, it identifies itself, provides its location to the tower,

and receives acknowledgment from the tower. The tower with the "strongest,

clearest" signal is the one to which the cell phone will "more than likely"

connect. This is known as the "serving cell" and is not necessarily the closet in

proximity to the cell phone, as the closest tower may not be operative, or its

signal may be blocked by an obstruction, such as a building or natural feature.

The cell phone surveys other towers around the serving cell, measuring the

signal strength of those towers. If a cell phone is in an area of overlapping

coverage, it may switch back and forth between serving cells.


                                                                            A-5486-16T2
                                         4
      The cell phone idles on the serving cell until the user initiates a call. At

that point, the cell phone communicates with the tower, indicating that it is

trying to make a call. The tower thereafter authorizes the call. If the tower is

operating at capacity, it will reroute the cell phone to another nearby tower,

provided the cell phone's connection to that tower is sufficient to support the

call. A cell phone can communicate with a tower only if the cell phone is within

the tower's range. An at-capacity tower, therefore, will never reroute a cell

phone to a tower to which the cell phone cannot connect. Towers in the Newark

area reach capacity an average of less than two percent of the time. A call placed

in an area of overlapping coverage could be routed to either tower providing

coverage.

      A record is generated when a cell phone connects to a tower to make a

call. The record contains the calling number, the number dialed, the date and

time that a call was placed, the end time of the call, the duration of the call, and

the last tower to which the phone was connected during the call. No record is

created if the cell phone is unable to connect to a tower when attempting a call.

An ongoing call may be transferred from tower to tower, particularly if the cell

phone is moving, but may also be transferred when a tower approaches capacity.

Only the towers at which a call originates and ends are recorded.


                                                                            A-5486-16T2
                                         5
      Hauger explained that historical cell site data analysis provides "the

approximate area . . . of where a cell phone was when it connected" to an

identified sector of a tower at a particular date and time. When Hauger examines

a call to a particular sector of a tower, he depicts on a map a "footprint" that

roughly reflects a 120-degree, open-ended pie-wedge shape of intended

coverage for that sector. The depiction does not have "a nice crisp line" showing

the outer bound of a tower's signal. In addition, the actual coverage area may

extend beyond the depicted coverage area.

      Hauger specified that although he can show a phone communicated within

the footprint of the sector of a tower on a particular date and time, he is not able

to place the phone at any specific location within the footprint. As he explained,

"[a]ll I can do is say the phone utilized this particular tower or this particular

sector for this particular call, and that sector most likely covers this area." He

admitted "there's no way to measure how far away . . . a phone was from a

particular tower" and his analysis would "never be able to tell you where a phone

was down to the address or to the corner[.]"

      The State introduced maps created by Hauger depicting his opinion of the

roughly pie-wedge shaped area covered by a sector of T-Mobile Tower 3397

(Tower 3397) and Sprint Tower 41-2 (Tower 41-2), both of which are near the


                                                                            A-5486-16T2
                                         6
site of the shooting. Data from the communications companies identified these

towers as having hosted three transmissions between cell phones belonging to

defendant and Hoskins on February 8, 2014, between 7:30 p.m. and 7:34 p.m.,

the date and approximate time of the shooting. The calls involved a cell phone

assigned a T-Mobile number and a cell phone assigned a Sprint number. The

murder site was near the coverage areas depicted on the maps.

      The T-Mobile number called the Sprint number first, using Tower 3397

near the intersection of Orange and Seventh Streets in Newark, about a block

from the crime scene. The data indicated that the call used an antenna serving

sector seven of the tower. Using a chart depicting the pie-wedge shaped area

covered by the sector seven antenna overlaid on a map of Newark, Hauger

opined the cell phone with the T-Mobile number was in the pie-wedge shaped

area near the murder scene. He also opined that the T-Mobile phone number the

received two calls from Tower 3397's sector seven in the next two minutes.

      Based on the historical cell phone data from the cell phone assigned the

Sprint phone number, Hauger opined that the Sprint cell phone communicated

with Tower 41-2, which was close to Tower 3397 and also near the intersection

of Orange and Seventh Streets, for four calls during the approximate time of the




                                                                        A-5486-16T2
                                       7
shooting: the three calls from the T-Mobile phone number and a fourth incoming

call from a phone number in the 862 area code.

      Although he relied on the map depicting the 120-degree intended service

area of the towers, Hauger testified that "there is no way to tell without doing

drive tests what the actual . . . limit of the sector is" for the towers. He conducted

a drive test for the two towers on December 22, 2015, twenty-two months after

the shooting. He described the process of conducting a drive test as follows:

             [I u]se a device called . . . [a] gladiator autonomous
             receiver, it's a scanner, built by Venture Designs which
             is a scanning company that builds scanners for the cell
             phone industry. So I take the scanner and program it
             for Sprint and T-Mobile and I get in my car. What the
             scanner is doing is it's listening for the Sprint and T-
             Mobile frequencies where cell phones communicate on.
             And it's measuring the signal strength of the towers as
             I drive by. So I plug in the machine, set it up to measure
             the right – the appropriate characters – or carriers, and
             basically drive every street in the area so the scanner
             listens to the cellular environment and it determines
             where a particular phone would go if a phone was
             placed at that particular moment. It does it like two or
             three times a second. So what a drive test is is a – the
             best way that we have currently of determining what the
             actual cellular footprint of a tower is, without the
             theoretical pie wedges that we've been showing. It is
             the measured radio frequency.

      He testified that he was trained with the Gladiator device annually and

that the device was examined for calibration annually. Testifying that cell phone


                                                                              A-5486-16T2
                                          8
carriers use a similar device for signal strength testing, Hauger stated that he

believed the Gladiator device is capable of providing a reliable scientific opinion

on cell site coverage. Hauger's drive test enabled him to produce a map with a

shaded area displaying the Gladiator's readout of the extent of the "dominant

coverage area" of the towers. Testifying the "dominant coverage area" displays

the range in which a cell phone would "more than likely" connect to that tower,

Hauger clarified that a cell phone would not connect to that tower one-hundred

percent of the time, especially near the edges of the "blob" where it would

potentially connect to a neighboring tower. Yet, according to Hauger, the drive

test largely confirmed the pie-wedge shaped coverage predictions he created.

      Hauger acknowledged limitations to the drive-test, including that he can

only drive down streets and could not go in homes or non-public buildings.

Therefore, the Gladiator produces readings while driving down each street and

interpolates the outer bounds of the signal coverage map between streets at the

edge of the coverage area and in houses and other buildings. It is important to

note that the "dominant coverage area" as depicted by Hauger appears as a




                                                                           A-5486-16T2
                                        9
meandering shape, with disconnected outlying areas, missing inner portions, and

arms reaching out in multiple directions. 1

      Hauger noted that terrain, including buildings and "any kind of large glass

structure, large glass and concrete," a bus, and even creek beds and water can

affect a cell phone connecting to the geographically closest cell tower.

Specifically, Hauger agreed that office buildings in Newark would affect which

tower a phone "saw best" and that radio waves could bounce off buildings or

other structures. He testified that "with reflection, refraction, that sort of thing,

radio waves do all kinds of things when confronted with steel, concrete, you

know, glass, that sort of thing." Hauger explained that a cell phone's ability to

communicate with a tower could be affected by

             [a]ny new construction. Any large buildings. Well,
             new construction is kind of – I really wouldn't want to
             say all new construction because, I mean, somebody
             could do a – build a sidewalk and that wouldn't effect
             anything. But any large buildings that are either
             demolished or constructed in that general area,
             especially the area I drove relative to February of 2014,
             that would affect [the tower signal footprint], yes.




1
  Hauger clarified that a drive test only presents a footprint of signal strength at
ground level, which does not reflect dominant signal strength if the phone is
elevated, such as on a rooftop, or depressed, such as in a basement, or inside a
private building.
                                                                             A-5486-16T2
                                        10
      Hauger testified that there were multi-story apartment and commercial

buildings in the area of the towers he tested. He conceded he did not examine

building records or any other source to determine if any buildings were built or

demolished in the twenty-two months between the crime and the drive test. He

testified that he "certainly didn't notice any[ buildings that were] brand-new."

      Hauger consulted T-Mobile records and a legal compliance attorney for

T-Mobile to confirm there was no change to Tower 3397's location, antenna tilt,

or its tower angle/azimuth between the date of the shooting and the date of the

drive test. On Tower 41-2, all tower elements remained the same, except during

the twenty-two-month period the antenna angle was decreased by two degrees.

Hauger offered the opinion that this change could potentially expand the tower's

footprint slightly. He could not explain the basis for that opinion, apart from

saying "a bunch of people" told him what the effect of the change in the antenna

angle would be.

      Hauger did not consult maintenance logs to determine if the towers

surrounding Tower 3397 and Tower 41-2 were operational on February 8, 2014.

He acknowledged if the surrounding towers were not operational, the two

relevant towers would have had expanded cellular range footprints.




                                                                          A-5486-16T2
                                       11
      Zahra's testimony disputed Hauger's assumption that a cell phone will

always connect to the tower from which it detects the strongest, clearest signal.

He testified that when the tower with the strongest, clearest signal is at or near

capacity, a cell phone will be rerouted to a neighboring tower with sufficient

coverage. In addition, after reviewing Hauger's coverage maps, Zahra agreed

Hauger's approximations of the two tower's coverage areas were fair. 2

      On December 9, 2016, the court issued a written opinion and order

denying defendant's motion. The court noted that the parties did not dispute

Hauger's expertise or that the field of historical cell site data analysis was

beyond the ken of the average juror. The only issue before the court was whether

the methods used by Hauger to reach his opinions were sufficiently reliable to

admit his testimony and the exhibits he created.

      The court rejected defendant's two primary objections to the reliability of

Hauger's methods – that calls may be rerouted from overloaded towers and that

Hauger's drive testing was limited by his inability to enter homes and other non-

public places. The court accepted Zahra's testimony that calls are rerouted from

the tower with the strongest signal when that tower is at or near capacity, which


2
  Notably, the record contains no evidence with respect to the live tracking of a
cell phone using GPS coordinates, triangulation of radio signals, or otherwise.
The data examined by the experts concerned the historical use of cell phones.
                                                                          A-5486-16T2
                                       12
the court determined occurred only approximately two percent of the time. In

addition, the court observed that a rerouted call will be sent to a tower with

coverage in the area in which the cell phone is located, resulting in a minimal

geographic deviation from the coverage area of the tower from which it was

rerouted. In addition, the court, while recognizing the limitations of the drive

test and the pie-wedge shaped maps depicting the intended coverage area of the

two towers, concluded that the methods used by Hauger were sufficiently

reliable to render the maps and his testimony admissible.

      On June 6, 2017, defendant withdrew his not guilty plea and entered a

negotiated plea of guilty to second-degree manslaughter, N.J.S.A. 2C:11-

4(b)(1), and second-degree unlawful possession of a weapon, N.J.S.A. 2C:39-

5(b)(1), reserving his right to appeal the trial court's decision.   The court

sentenced defendant pursuant to the plea agreement to a six-year term of

imprisonment with an eighty-five-percent parole ineligibility period pursuant to

the No Early Release Act (NERA), N.J.S.A. 2C:43-7.2, as well as to a three-

year period of special parole supervision for manslaughter, and a concurrent

five-year term of imprisonment for the weapons offense, with forty-two months

of parole ineligibility pursuant to the Graves Act, N.J.S.A. 2C:43-6(c). The

remaining counts were dismissed.


                                                                        A-5486-16T2
                                      13
      This appeal followed. Defendant raises the following arguments for our

consideration:

            POINT I

            THE TRIAL COURT'S RULING ADMITTING THE
            RESULTS OF THE DRIVE TEST AND HAUGER'S
            OPINION ON THE LOCATION OF DEFENDANT'S
            CELL PHONE NEAR THE TIME OF THE
            HOMICIDE SHOULD BE REVERSED BECAUSE
            THE "CAST" METHODOLOGY UPON WHICH
            THEY RELY IS: 1) INHERENTLY UNRELIABLE;
            AND 2) ESPECIALLY UNRELIABLE IN THIS
            CASE.

            POINT II

            THE TRIAL COURT'S RULING ADMITTING THE
            PIE[-]WEDGE MAPS SHOULD BE REVERSED
            BECAUSE THEY ARE NOT RECOGNIZED BY THE
            RADIO      FREQUENCY       ENGINEERING
            COMMUNITY, AND IN ANY EVENT, THE
            GEOGRAPHICAL REPRESENTATIONS THEY
            EMBODY ARE TOO CRUDE TO AID THE JURY.

                                       II.

      Expert testimony is admissible when "scientific, technical, or other

specialized knowledge will assist the trier of fact to understand the evidence or

to determine a fact in issue" and the proposed expert has the requisite

"knowledge, skill, experience, training, or education" to form an expert opinion.




                                                                         A-5486-16T2
                                      14
N.J.R.E. 702. The rule creates three requirements for admission of expert

testimony:

             (1) the intended testimony must concern a subject
             matter that is beyond the ken of the average juror; (2)
             the field testified to must be at a state of the art such
             that an expert's testimony could be sufficiently reliable;
             and (3) the witness must have sufficient expertise to
             offer the intended testimony.

             [State v. Kelly, 97 N.J. 178, 208 (1984).]

As noted above, only the second factor is at issue here.

      It is well-established that New Jersey courts apply the general acceptance

within a scientific community test set forth in Frye v. United States, 293 F. 1013

(D.C. Cir. 1923), to determine the admissibility of expert testimony in criminal

cases. While our Supreme Court "adopted the factors identified in Daubert v.

Merrell Dow Pharms., Inc., 509 U.S. 579, 593-95 (1993), and a methodology-

based approach for determining scientific reliability in certain areas of civil law,

[the Court has] not altered [its] adherence to the general acceptance test for

reliability in criminal matters." State v. Cassidy, 235 N.J. 482, 492 (2018).

             "Proof of general acceptance within a scientific
             community can be elusive," and "[s]atisfying the test
             involves more than simply counting how many
             scientists accept the reliability of the proffered
             [technique]." State v. Harvey, 151 N.J. 117, 171
             (1997).     General acceptance "entails the strict
             application of the scientific method, which requires an

                                                                            A-5486-16T2
                                        15
            extraordinarily high level of proof based on prolonged,
            controlled, consistent, and validated experience." Ibid.
            (quoting Rubanick v. Witco Chem. Corp., 125 N.J. 421,
            436 (1991)). The proponent of the technique has the
            burden to "clearly establish" general acceptance, State
            v. Johnson, 42 N.J. 146, 171 (1964), and may do so
            using "(1) expert testimony, (2) scientific and legal
            writings, and (3) judicial opinions," State v. Cavallo, 88
            N.J. 508, 521 (1982)[.]

            [Ibid. (alterations in original).]

"Thus, the test in criminal cases [is] whether the scientific community generally

accepts the evidence."      Harvey, 151 N.J. at 170.        To establish general

acceptance, "the party proffering the evidence need not show infallibility of the

technique nor unanimity of its acceptance in the scientific community."

Cassidy, 235 N.J. at 492. "[T]he State's burden is to prove that the . . . test and

the interpretation of its results are non-experimental, demonstrable techniques

that the relevant scientific community widely, but perhaps not unanimously,

accepts as reliable." Harvey, 151 N.J. at 171.

      "Whether expert testimony is sufficiently reliable to be admissible under

N.J.R.E. 702 is a legal question we review de novo." State v. J.L.G., 234 N.J.

265, 301 (2018). "When reviewing a decision on the admission of scientific

evidence, an appellate court should scrutinize the record and independently




                                                                           A-5486-16T2
                                        16
review the relevant authorities, including judicial opinions and scientific

literature." Harvey, 151 N.J. at 167.

      Having carefully reviewed the record in light of the applicable precedents,

we affirm the trial court's conclusion that historical cell site data analysis is

generally accepted in the scientific community and sufficiently reliable to be

admitted into evidence to show the general location of a cell phone at a particular

time. We therefore affirm the court's December 9, 2016 order to the extent that

it reaches the same conclusion. However, we conclude that shortcomings in

Hauger's methodology render the opinion he offered in this case unreliable. As

a result, we reverse that portion of the trial court's order permitting the admission

of Hauger's testimony and the exhibits he created, and remand for further

proceedings. We add the following comments.

                                        III.

      There is no published opinion in this State squarely addressing the

admissibility of historical cell site data analysis in a criminal matter. A number

of out-of-state and federal precedents, however, are instructive.

      Federal courts have been receptive to expert testimony regarding

historical cell site data analysis. "District courts that have been called upon to

decide whether to admit historical cell-site analysis have almost universally


                                                                             A-5486-16T2
                                        17
done so." United States v. Hill, 818 F.3d 289, 297 (7th Cir. 2016); accord United

States v. Reynolds, 626 Fed. Appx. 610, 616-17 (6th Cir. 2015) (allowing

historical cell site data analysis to show where parties other than defendant were

not); United States v. Schaffer, 439 F. App'x 344, 347 (5th Cir. 2011)

(concluding that the field of historical cell site data analysis "is neither untested

nor unestablished"); United States v. Weathers, 169 F.3d 336, 339 (6th Cir.

1999) (admitting expert testimony on historical cell site data analysis); United

States v. Jones, 918 F. Supp. 2d 1, 5 (D.D.C. 2013) (finding "the use of cell

phone location records to determine the general location of a cell phone" to be

both widely accepted and "based on reliable methodology"); United States v.

Evans, 892 F. Supp. 2d 949, 955-56 (N.D. Ill. 2012) (finding "granulization

theory" to be unreliable science, but still finding other historical cell site data

analysis methods have been adequately tested).

      So too have the courts of other States. State v. DePaula, 166 A.3d 1085,

1097-99 (N.H. 2017) (admitting historical cell site data analysis as lay witness

testimony); State v. Johnson, 797 S.E.2d 557, 563 (W.Va. 2017); Pullin v. State,

534 S.E.2d 69, 71 (Ga. 2000); Wilson v. State, 195 S.W.3d 193, 200-02 (Tex.

Crim. App. 2006) (allowing a Sprint employee to testify as an expert on

historical cell site data analysis); contra Phillips v. State, 163 A.3d 230, 234


                                                                             A-5486-16T2
                                        18
(Md. Ct. App. 2017) (noting trial court found the State failed to establish the

FBI agent's drive tests were generally accepted in the relevant community).

      Courts, however, have barred admission of expert testimony on historical

cell site data analysis where the method used by a particular expert renders the

testimony unreliable.   See generally Omnipoint Commc'n. Enters., L.P. v.

Zoning Hearing Bd., 331 F.3d 386, 399 (3rd Cir. 2003) (finding a lack of drive

test data renders an expert's opinion on signal strength unsupported); United

States v. Sepulveda, 115 F.3d 882, 891 (11th Cir. 1997) (finding the expert's

testimony lacked precision and thus did not support the particular premise at

issue).

      This court has allowed expert testimony on drive testing in civil matters

for the purpose of showing lackluster cell coverage in a municipality. N.Y.

SMSA Ltd. v. Twp. of Mendham Zoning Bd. of Adjustment, 366 N.J. Super.

141, 150 (App. Div. 2004); N.Y. SMSA, L.P. v. Bd. of Adjustment, 370 N.J.

Super. 319, 337 (App. Div. 2004); Sprint Spectrum, L.P. v. Zoning Bd. of

Adjustment, 360 N.J. Super. 373, 379 (App. Div. 2003); Sprint Spectrum, L.P.

v. Borough of Upper Saddle River Zoning Bd. of Adjustment, 352 N.J. Super.

575, 587-88 (App. Div. 2002). We have recognized that a cell phone company




                                                                        A-5486-16T2
                                      19
performing a drive test "to determine the gap in coverage was accurate and

accepted in the industry[.]" Sprint Spectrum, 360 N.J. Super. at 389.

      The Seventh Circuit found that "[h]istorical cell-site analysis can show

with sufficient reliability that a phone was in a general area, especially in a well-

populated one.    It shows the cell sites with which the person's cell phone

connected, and the science is well understood." Hill, 818 F.3d at 298 (noting

that the analysis "requires specialized training" which was satisfied by the FBI

Special Agent in the matter, who had employed the method extensively). The

court, however, made clear that historical cell site data analysis must be

presented with caution:

             Our concern is that the jury may overestimate the
             quality of the information provided by this analysis.
             We therefore caution the government not to present
             historical cell-site evidence without clearly indicating
             the level of precision—or imprecision—with which
             that particular evidence pinpoints a person's location at
             a given time. The admission of historical cell-site
             evidence that overpromises on the technique's
             precision—or fails to account adequately for its
             potential flaws—may well be an abuse of discretion.

             [Id. at 299.]

      Hauger adequately conveyed the limitations inherent in historical cell site

data analysis, acknowledging its limitation of providing only a general area in

which a cell phone could be located.         Had this matter proceeded to trial,

                                                                             A-5486-16T2
                                        20
defendant's counsel would have been free to explore through cross-examination

the limitations of Hauger's analysis.

      Our analysis also applies to the charts Hauger created to depict the

intended pie-wedge shaped coverage area of the towers. Pie-shaped wedges are

not intended to portray a cell tower sector's actual coverage area. Jones, 918 F.

Supp. 2d at 5.

            [T]he size of the pie-shaped wedge is unimportant. The
            radius of the sides of the wedge, and thus the distance
            of the connecting arc from the cell tower, is not meant
            to convey the coverage area of the signal coming from
            that antenna. The wedge is drawn in simply to indicate
            the direction of the sector to which the phone
            connected. The signal from that antenna could extend
            less far or farther away from the cell tower than the
            length of the pie-shaped wedges. Thus, because [the
            FBI Special Agent] does not purport to portray the
            "coverage area" of any particular cell tower or antenna,
            he cannot be said to have used an unreliable
            methodology in doing so.

            [Ibid.]

      Both experts agreed that pie-wedge charts generate a reliable estimation

of the coverage area of a given cell tower sector. Although defendant rightly

points out that the drive test reflected a coverage footprint that exceeded the

120-degree pie wedge in some places and contained gaps within the pie wedge

in others, Hauger used the pie-wedge shaped areas solely as a starting point


                                                                         A-5486-16T2
                                        21
before his drive test. Further, Hauger made the limitations inherent in pie-wedge

charts clear throughout his testimony, acknowledging they are merely an

estimation and starting point, not an actual footprint boundary. Had this matter

proceeded to trial presumably those limitations would have been made known

to the jury.

                                        IV.

      It is undisputed that a tower's footprint can shift over time due to changes

in the surrounding environment. "[B]ecause radio waves extend out horizontally

and then descend, coverage is affected by the surrounding topography . . . ."

Sprint Spectrum, L.P., 360 N.J. Super. at 379. "While the proximity of the user

is a significant factor in determining the cell tower with which the cell phone

connects, it is not the only one . . . . [O]ther factors include . . . geography and

topography . . . and 'environmental and geographical factors.'" Hill, 818 F.3d at

295-96 (quoting Aaron Blank, The Limitations and Admissibility of Using

Historical Cellular Site Data to Track the Location of a Cellular Phone, 18 Rich.

J.L. & Tech. 3, 5 (2011)). "[S]ignal strength may depend upon environmental

and geographical factors, including the weather, topography, and level of urban

development." Blank, 18 Rich. J.L. & Tech. at 3.




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                                        22
      Hauger acknowledged that because he did not examine construction

records or any other source of information he did not know whether any

buildings or other structures were built or destroyed in or around Tower 3397

and Tower 41-2 in the twenty-two months between the shooting and his drive

test. If there were buildings erected in those months, the coverage map for the

towers, as measured during Hauger's drive test, could represent a smaller

dominant signal range than existed at the time of the shooting. If buildings were

destroyed during that period, Hauger's drive test coverage map might show a

larger dominant signal range than existed at the time of the shooting.

      Although we affirm the court's conclusion that a drive test is a generally

accepted method of historical cell site data analysis, we conclude that Hauger's

failure to investigate environmental changes in the area of the two towers in the

twenty-two months between the shooting and the drive test render his opinion

in this matter unreliable. Hauger's observation that he did not notice any new

construction during the drive test is insufficient to render his drive test reliable.

We therefore reverse the December 9, 2016 order to the extent that it permitted

the admission of Hauger's testimony and the exhibits he created.




                                                                             A-5486-16T2
                                        23
      To the extent we have not specifically addressed any of defendant's

remaining arguments it is because we conclude they lack sufficient merit to

warrant discussion in a written opinion. R. 2:11-3(e)(2).

      Affirmed in part, reversed in part, and remanded for proceedings

consistent with this opinion. We do not retain jurisdiction.




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