                         Nebraska Advance Sheets
	                       HALL v. COUNTY OF LANCASTER	969
	                              Cite as 287 Neb. 969

it deems just.24 Because there is no issue of fact and the City
is entitled to judgment as a matter of law, we determine the
controversy accordingly.
                      CONCLUSION
   We conclude that the improvement unit mandating the
paving of one block of Donna Street, which intersected Jean
Drive, was plainly authorized by the second sentence of
§ 18-2001. We reverse the judgment of the district court and
remand the cause with direction to enter judgment in favor of
the City.
                   R eversed and remanded with direction.

24	
      U.S. Bank Nat. Assn. v. Peterson, 284 Neb. 820, 823 N.W.2d 460 (2012).




          Jeff Hall, appellee and cross-appellee, v. County
             of Lancaster, appellant and cross-appellee,
                 and Norris School District No. 160,
                    appellee and cross-appellant.
                                    ___ N.W.2d ___

                        Filed April 18, 2014.    No. S-13-724.

 1.	 Tort Claims Act. Whether the allegations made by a plaintiff present a claim that
     is precluded by exemptions set forth in the State Tort Claims Act is a question
     of law.
 2.	 Political Subdivisions Tort Claims Act: Tort Claims Act. The Political
     Subdivisions Tort Claims Act includes a discretionary function exception similar
     to that contained in the State Tort Claims Act, and thus, cases construing the State
     Tort Claims Act exception are equally applicable to the discretionary function
     exception in the Political Subdivisions Tort Claims Act.
 3.	 Political Subdivisions Tort Claims Act: Appeal and Error. An appellate court
     has an obligation to reach its conclusion on whether a claim is precluded by
     exemptions set forth in the Political Subdivisions Tort Claims Act independent
     from the conclusion reached by the trial court.
 4.	 Political Subdivisions Tort Claims Act: Immunity: Waiver. The Political
     Subdivisions Tort Claims Act provides limited waivers of sovereign immunity
     which are subject to statutory exceptions.
 5.	 Pretrial Procedure: Parties. A pretrial order is binding upon the parties.
 6.	 Pretrial Procedure: Pleadings. The issues set out in a pretrial order supplant
     those raised in the pleadings.
    Nebraska Advance Sheets
970	287 NEBRASKA REPORTS


 7.	 Immunity: Waiver. Sovereign immunity is an affirmative defense that can
     be waived.
 8.	 Political Subdivisions Tort Claims Act: Appeal and Error. In actions brought
     under the Political Subdivisions Tort Claims Act, an appellate court will not dis-
     turb the factual findings of the trial court unless they are clearly wrong.
 9.	 Judgments: Appeal and Error. When determining the sufficiency of the evi-
     dence to sustain the trial court’s judgment, it must be considered in the light most
     favorable to the successful party; every controverted fact must be resolved in
     favor of such party, and it is entitled to the benefit of every inference that can be
     deduced from the evidence.
10.	 Negligence: Proof. In order to recover in a negligence action, a plaintiff must
     show a legal duty owed by the defendant to the plaintiff, a breach of such duty,
     causation, and damages.
11.	 Trial: Negligence: Proximate Cause. Determination of causation is ordinarily a
     matter for the trier of fact.
12.	 Proximate Cause: Words and Phrases. A proximate cause is a cause that pro-
     duces a result in a natural and continuous sequence and without which the result
     would not have occurred.
13.	 Negligence: Proximate Cause: Proof. To establish proximate cause, the plaintiff
     must meet three basic requirements: (1) Without the negligent action, the injury
     would not have occurred, commonly known as the “but for” rule; (2) the injury
     was a natural and probable result of the negligence; and (3) there was no efficient
     intervening cause.
14.	 Trial: Judgments: Evidence: Appeal and Error. Where neither party requests
     that the trial court make specific findings of fact and conclusions of law, if there
     is a conflict in the evidence, the appellate court in reviewing the judgment ren-
     dered will presume that the controverted facts were decided in favor of the suc-
     cessful party, and the findings will not be disturbed unless clearly wrong.
15.	 Judgments. In the absence of a request by a party for specific findings, a trial
     court is not required to make detailed findings of fact and need only make its
     findings generally for the prevailing party.
16.	 Trial: Negligence: Damages: Appeal and Error. Because the purpose of com-
     parative negligence is to allow triers of fact to compare relative negligence and
     to apportion damages on that basis, the determination of apportionment is solely
     a matter for the fact finder, and its action in this respect will not be disturbed on
     appeal if it is supported by credible evidence and bears a reasonable relationship
     to the respective elements of negligence proved at trial.
17.	 Appeal and Error. An appellate court is not obligated to engage in an analysis
     that is not necessary to adjudicate the case and controversy before it.

  Appeal from the District Court for Lancaster County: Steven
D. Burns, Judge. Affirmed in part, and in part reversed and
remanded for further proceedings.
  Joe Kelly, Lancaster County Attorney, and Richard C.
Grabow for appellant.
                  Nebraska Advance Sheets
	                HALL v. COUNTY OF LANCASTER	971
	                       Cite as 287 Neb. 969

  Jeanelle R. Lust, of Knudsen, Berkheimer, Richardson &
Endacott, L.L.P., for appellee Norris School District No. 160.

  Terry R. Wittler, of Cline, Williams, Wright, Johnson &
Oldfather, L.L.P., and Vincent M. Powers, of Vincent M.
Powers & Associates, for appellee Jeff Hall.

  Heavican, C.J., Connolly, Stephan, McCormack, Miller-
Lerman, and Cassel, JJ., and Bishop, Judge.

    Cassel, J.
                        I. INTRODUCTION
   A pickup truck and a schoolbus collided at a rural “blind
intersection,” where a stop sign facing the truck was missing.
The district court determined that both drivers were negligent.
But the court also found that the county was liable, reasoning
that it would have discovered the sign was missing if it had
conducted regular sign inspections. Because there was no evi-
dence to support that premise, the court was clearly wrong in
determining that the county’s lack of a sign-inspection policy
was a proximate cause of the accident. We reverse the judg-
ment finding the county liable and remand the cause for a
reallo­ ation of liability between the driver of the pickup truck
      c
and the school district based upon the existing record.

                       II. BACKGROUND
                     1. Factual Background
   On August 24, 2009, a pickup truck operated by Jeff Hall
collided with a bus owned by Norris School District No. 160
(Norris) and operated by Ronny Aden. The collision occurred
at the intersection of South 25th Street and Gage Road in
Lancaster County, Nebraska. South 25th Street and Gage Road
are gravel country roads with a speed limit of 50 miles per
hour. Neither vehicle was exceeding the speed limit. Hall was
proceeding south on South 25th Street, while the bus was east-
bound on Gage Road. The bus was on Hall’s right. A diagram
from an exhibit in evidence illustrates the intersection and the
direction of travel of each vehicle.
    Nebraska Advance Sheets
972	287 NEBRASKA REPORTS




   The intersection had limited visibility and was “blind” for
both drivers. Corn planted near the road obstructed Hall’s
view to the right and Aden’s view to the left. The stop sign
for southbound traffic on South 25th Street was missing at the
time of the collision. There was no evidence that the County of
Lancaster (County) had actual notice of the missing stop sign
prior to the accident. Aden, who had driven the same bus route
hundreds of times since 2007, had seen a vehicle at the inter-
section only once or twice a year. He did not believe there was
a stop sign at the intersection, but, rather, believed it to be an
“open intersection.” Hall had not previously traveled on South
25th Street, and he assumed there would be a stop sign for east
and west traffic, because he did not have one.
   Hall testified that his rate of speed as he approached the
intersection was between 45 and 50 miles per hour and that he
slowed as he got closer to the intersection because he always
slowed as he approached an intersection on a “county road.”
He estimated his speed to be 40 miles per hour as he entered
the intersection. Aden accelerated as he approached the inter-
section, but the bus did not increase in speed, because it was
traveling up an incline. Aden told an investigating officer that
                   Nebraska Advance Sheets
	                 HALL v. COUNTY OF LANCASTER	973
	                        Cite as 287 Neb. 969

he was driving 47 to 48 miles per hour. Aden testified that a
safe speed for the bus going into the blind intersection would
have been 20 to 25 miles per hour.
   Ted Sokol, Ph.D., an engineer performing accident recon-
struction, concluded that there was not enough time for either
driver to react once the vehicles became visible to one another.
According to Sokol, Hall entered the intersection first, but the
vehicles entered at approximately the same time. Sokol opined
that Aden should have been more cautious as he approached
or entered the intersection and that Aden could have avoided
the accident by not assuming traffic on South 25th Street was
going to stop and by approaching at a much lower speed so
that he could have stopped before entering the intersection.
According to Sokol, the bus’ maximum speed would have
needed to be about 23 miles per hour in order for Aden to
perceive and react in time to stop before getting to the west
edge of South 25th Street. Sokol testified that Hall could have
stopped without entering the intersection if Hall had slowed to
18 miles per hour.
   Benjamin Railsback, a mechanical engineer, concluded that
the speed of the vehicles was not a contributing factor in the
accident. He testified that due to the sight obstruction created
by the corn, neither vehicle was visible to the other at a point
in time where either driver had the opportunity to perceive
and react in order to avoid the accident. He testified that the
vehicles would have entered the intersection within a fraction
of a second of one another. Railsback did not have any criti-
cism of Aden’s driving, because Aden “acted reasonably and
drove reasonably through the intersection.”
   Hall suffered substantial injuries as a result of the accident.
Aden and the children who were being transported in the bus
also suffered personal injuries. Additionally, Norris incurred
property damage.

                  2. P rocedural Background
   Hall sued the County and Norris, alleging that the colli-
sion was proximately caused by the negligence of the County
and of Aden. Hall alleged that Aden was negligent in failing
to yield the right-of-way, operating the schoolbus too fast for
    Nebraska Advance Sheets
974	287 NEBRASKA REPORTS



the conditions, failing to keep proper control of the bus, and
failing to keep a proper lookout. He alleged that the County
was negligent in failing to have a traffic control device in
place, failing to maintain the stop sign that had been in place,
and “failing to take effective practices to ensure that a traffic
control device would be in place.” Hall further alleged that the
County failed to have in place any type of policy or practice
to inspect or determine if a stop sign had been removed from
an intersection.
   The County’s responsive pleading alleged that it was immune
from suit. The County alleged that Hall was negligent in sev-
eral respects and that he was negligent in such a degree as to
bar recovery or to proportionately diminish the amount sought
as damages. The County further alleged that the negligence of
Hall and Aden were efficient intervening causes.
   Norris filed an answer, counterclaim, and cross-claim.
Norris alleged that Hall was contributorily negligent in a
degree equal to or greater than the total negligence alleged
against Norris and the County. Norris claimed that Hall was
negligent by failing to yield the right-of-way to Norris’ school-
bus, failing to have his vehicle under proper and reasonable
control, operating his vehicle at a speed greater than was
reasonable under the conditions, and failing to keep a proper
lookout. Norris asserted a counterclaim against Hall, alleging
that he proximately caused damage and injuries to Norris by
virtue of his negligent acts and omissions. Norris’ cross-claim
against the County alleged that the County was negligent for
failing to discover through reasonable inspection that the stop
sign was missing at the intersection and that such negligence
was a proximate cause of injuries to Aden, injuries to the
children on the bus, and property damage incurred by Norris.
Norris sought judgment against both Hall and the County in
the amount of $157,847.83.
   In the County’s amended answer to Norris’ cross-claim, the
County alleged that it was immune from suit. The County fur-
ther alleged that it did not have actual or constructive notice of
the malfunction, destruction, or removal of the stop sign. The
joint pretrial conference order did not expressly identify immu-
nity from suit as a legal issue presented by the case.
                        Nebraska Advance Sheets
	                      HALL v. COUNTY OF LANCASTER	975
	                             Cite as 287 Neb. 969

                  3. District Court’s Decision
   Following a bench trial, the district court entered judg-
ment in Hall’s favor. The court stated that “regardless which
driver had the right[-]of[-]way, both drivers were negligent
for approaching the intersection at a rate of speed that was too
fast for the circumstances.” The court found that Aden’s neg-
ligence was greater than that of Hall. As to Norris’ claims, the
court found that Aden’s negligence was 50 percent and denied
Norris’ claims for recovery.
   The district court also found the County to be negligent.
The court determined that the County would have discov-
ered the stop sign was missing had it carried out a reason-
able inspection and that the absence of a regular inspection,
particularly during the high-risk time of year when crops are
mature in late summer and early fall, was not reasonable. The
court concluded that Aden’s and Hall’s conduct was foresee-
able. Ultimately, the court found the County liable, stating that
“[h]ad the stop sign been in placed [sic] it would have been
clearly visible to Hall so that he could have stopped at the
intersection and avoided the collision.”
   The court explicitly determined that the negligence of Norris
was 50 percent and that Hall’s percentage of negligence was 30
percent. The court also stated that the combined negligence of
Norris and the County was 70 percent. Thus, as the County and
Hall acknowledge, the court implicitly allocated the County’s
negligence as 20 percent. The court entered judgment against
Norris and the County, jointly and severally, in the amount
of $770,000. Additional findings of the district court will be
included in the analysis.
   The County timely appealed, and Norris filed a cross-
appeal. We moved the case to our docket under our statutory
authority to regulate the caseloads of the appellate courts of
this state.1
              III. ASSIGNMENTS OF ERROR
  The County assigns that the district court erred in failing to
determine that the County maintained its sovereign immunity

 1	
      Neb. Rev. Stat. § 24-1106(3) (Reissue 2008).
    Nebraska Advance Sheets
976	287 NEBRASKA REPORTS



for discretionary policy decisions made in relation to sign
inspections and related documentation.
   The County and Norris each assign error regarding the dis-
trict court’s ultimate determinations of negligence. The County
contends that the court erred in determining that the County’s
sign-inspection policies and documentation were so inadequate
as to give the County constructive notice of a missing stop
sign, in determining that the County’s failure to adopt an
adequate sign policy was a proximate cause of Hall’s dam-
ages, and in failing to determine that the acts of Hall and Aden
were efficient intervening causes for the claims of Norris and
Hall against the County so that any negligence against the
County could not be considered the proximate cause of Hall’s
or Norris’ damages. Norris assigns that the court erred in not
determining that Hall was more than 50 percent at fault as a
result of the court’s failure to make findings on violations of
the Nebraska Rules of the Road.2
   Norris also assigns that the district court erred in failing to
allocate Hall’s damages into economic and noneconomic dam-
ages and failing to allocate percentages of fault to Norris and
the County on Hall’s claims.
                        IV. ANALYSIS
                    1. Sovereign Immunity
                            (a) Issue
   The County argues that it maintained sovereign immunity
for decisions made regarding the adoption and implementation
of a sign-inspection policy. But Hall counters that the discre-
tionary function exception was not an issue at trial.
                     (b) Standard of Review
   [1-3] Whether the allegations made by a plaintiff present a
claim that is precluded by exemptions set forth in the State Tort
Claims Act is a question of law.3 The Political Subdivisions

 2	
      See Neb. Rev. Stat. §§ 60-601 to 60-6,381 (Reissue 2010, Cum. Supp.
      2012 & Supp. 2013).
 3	
      See Fickle v. State, 273 Neb. 990, 735 N.W.2d 754 (2007), modified on
      other grounds 274 Neb. 267, 759 N.W.2d 113.
                      Nebraska Advance Sheets
	                    HALL v. COUNTY OF LANCASTER	977
	                           Cite as 287 Neb. 969

Tort Claims Act includes a discretionary function exception
similar to that contained in the State Tort Claims Act, and
thus, cases construing the State Tort Claims Act exception are
equally applicable to the discretionary function exception in
the Political Subdivisions Tort Claims Act.4 An appellate court
has an obligation to reach its conclusion on whether a claim is
precluded by exemptions set forth in the Political Subdivisions
Tort Claims Act independent from the conclusion reached by
the trial court.5

                     (c) Additional District
                         Court Findings
   The district court did not specifically reference Neb. Rev.
Stat. § 13-910 (Reissue 2007) or make any findings regarding
sovereign immunity or the discretionary function exception.

                          (d) Discussion
   [4] The Political Subdivisions Tort Claims Act provides
limited waivers of sovereign immunity which are subject to
statutory exceptions.6 If a statutory exception applies, the claim
is barred by sovereign immunity.7 The County argues that the
district court erred in implicitly determining that § 13-910(2)
did not apply to Hall’s theory that the County had construc-
tive notice of the missing stop sign by virtue of not adopting
an adequate sign-inspection policy. The County relies on the
statute stating that the Political Subdivisions Tort Claims Act
shall not apply to “[a]ny claim based upon the exercise or
performance of or the failure to exercise or perform a discre-
tionary function or duty on the part of the political subdivision
or an employee of the political subdivision, whether or not the
discretion is abused.”8

 4	
      See Shipley v. Department of Roads, 283 Neb. 832, 813 N.W.2d 455
      (2012).
 5	
      See Fickle, supra note 3.
 6	
      Shipley, supra note 4.
 7	
      Id.
 8	
      § 13-910(2).
    Nebraska Advance Sheets
978	287 NEBRASKA REPORTS



   The County’s responsive pleadings claimed immunity. The
County asserted that it was entitled to immunity because Hall’s
and Norris’ claims were based on the exercise or performance
of or the failure to exercise or perform a discretionary function
or duty on the part of a political subdivision or an employee
of the political subdivision.9 The County further alleged that
it was immune from suit, because the claim alleged by Norris
arose out of the malfunction, destruction, or unauthorized
removal of any traffic or road sign, signal, or warning device,
and that the County did not have actual or constructive notice
of such malfunction, destruction, or removal.10
   Hall claims that the County waived the issue of immunity.
He points out that the joint pretrial conference order listed only
three legal issues for trial: Norris’ negligence, the County’s
negligence, and Hall’s negligence. Indeed, the pretrial order
did not identify sovereign immunity or the discretionary func-
tion exception as an issue for trial. The district court did not
explicitly address immunity in its judgment. But the pretrial
order framed the claim against the County as including the
“fail[ure] to discover through reasonable inspection that the
stop sign was missing at the intersection where the collision
occurred.” This framed the issue in light of the provision of
§ 13-910(9) regarding actual or constructive notice of a miss-
ing sign.
   [5,6] The pretrial order is binding upon the parties.11 And
the issues set out in a pretrial order supplant those raised in
the pleadings.12 The joint pretrial conference order in this
case did not identify immunity as an issue, and it specifically
ordered that “trial of this case will be governed by the terms of
this pretrial conference order and the terms hereof supersede
all prior pleadings in this case.” This court has affirmed the
limiting of the issues at trial to those specified in the pretrial

 9	
      See id.
10	
      See § 13-910(9).
11	
      Olson v. England, 206 Neb. 256, 292 N.W.2d 48 (1980).
12	
      Cotton v. Ostroski, 250 Neb. 911, 554 N.W.2d 130 (1996).
                        Nebraska Advance Sheets
	                      HALL v. COUNTY OF LANCASTER	979
	                             Cite as 287 Neb. 969

order and limiting the admission of evidence to the issues thus
established on numerous occasions.13
   [7] Further, sovereign immunity is an affirmative defense
that can be waived. The exceptions set forth in § 13-910 are
affirmative sovereign immunity defenses to claims brought
pursuant to the Political Subdivisions Tort Claims Act.14 We
have interpreted exceptions to the State’s waiver of immu-
nity under both the State Tort Claims Act and the Political
Subdivisions Tort Claims Act as affirmative defenses that the
State must plead and prove.15 In Reimers-Hild v. State,16 the
defendants did not raise sovereign immunity as an affirmative
defense in their answer and the court’s pretrial order specified
that the sole issue at trial was whether the plaintiff’s claim
was timely filed. On appeal, the defendants argued that the
action against the State was barred by sovereign immunity.
We recognized that sovereign immunity implicated a juris-
dictional issue that may be raised at any time by any party,
but we declined to consider it because it was not raised in the
trial court. We noted that the record was created by stipula-
tion, that the parties apparently did not contemplate the sov-
ereign immunity issue at that time, and that we did not know
what arguments might have been made or evidence adduced
had the State raised a sovereign immunity defense in the dis-
trict court.

                          (e) Resolution
   By failing to identify sovereign immunity as an issue for
trial in the joint pretrial conference order, we conclude that
the County waived its claim that it was entitled to immu-
nity under the discretionary function exception contained in
§ 13-910(2).

13	
      See Cockrell v. Garton, 244 Neb. 359, 507 N.W.2d 38 (1993) (collecting
      cases).
14	
      Doe v. Omaha Pub. Sch. Dist., 273 Neb. 79, 727 N.W.2d 447 (2007).
15	
      Doe v. Board of Regents, 280 Neb. 492, 788 N.W.2d 264 (2010).
16	
      Reimers-Hild v. State, 274 Neb. 438, 741 N.W.2d 155 (2007).
    Nebraska Advance Sheets
980	287 NEBRASKA REPORTS



                    2. Negligence of County
                            (a) Issue
   The County argues that the district court erred in deter-
mining that it was liable because it did not have an adequate
sign-inspection policy. Evidence established that the County
did not have a written policy or a set schedule for conducting
sign inspections. The court determined that the County’s sign-
inspection procedures were so inadequate as to give the County
constructive notice of the missing sign. The County argues that
the court erred in determining that the County’s sign-inspection
procedures were a proximate cause of Hall’s damages.
                     (b) Standard of Review
   [8,9] In actions brought under the Political Subdivisions
Tort Claims Act, an appellate court will not disturb the fac-
tual findings of the trial court unless they are clearly wrong.17
When determining the sufficiency of the evidence to sustain
the trial court’s judgment, it must be considered in the light
most favorable to the successful party; every controverted
fact must be resolved in favor of such party, and it is entitled
to the benefit of every inference that can be deduced from
the evidence.18
                      (c) Additional Evidence
                              at Trial
   The Lancaster County engineering department maintained
over 800 miles of arterial roads in the county. Employees of
the engineering department were trained to look for damaged
or “down” signs while performing their work duties. As one
employee testified, “[P]atrol operators . . . out running the
roads . . . are [the County’s] first line of defense.” The sheriff’s
office also notified the County of signs that were missing. If a
stop sign was missing, the County tried to replace it as soon
as possible.
   Troy Foster, a laborer for the Lancaster County engineer-
ing department, mows ditches along the county roads. Foster

17	
      Blaser v. County of Madison, 285 Neb. 290, 826 N.W.2d 554 (2013).
18	
      Ginapp v. City of Bellevue, 282 Neb. 1027, 809 N.W.2d 487 (2012).
                   Nebraska Advance Sheets
	                 HALL v. COUNTY OF LANCASTER	981
	                        Cite as 287 Neb. 969

makes it to each “spot” in his area about twice a year, and he
mows each area once a year. Foster testified that when he first
began mowing, the district supervisor for the southeast area
of Lancaster County told him to look for damaged or “down”
signs while performing his job and to call the supervisor if such
a sign was found. Foster testified that during times of inclem-
ent weather or when he was not otherwise mowing, his duty
would be “to go around and look for signs that are down, lean-
ing, any kind of repairs that need to be done.” He testified that
signs are inspected “during our daily business or, you know, as
we are going from place to place, we check signs then.” There
was no pattern that he would follow, and he would not know if
a fellow employee had gone to the same place. Foster did not
make any record of where he had been to look for signs. Foster
testified that he was not given a map or chart showing the loca-
tion of signs within the county, but he also testified that at one
time, employees were given maps showing “by the sections”
where signs should be.
   Employees of the Lancaster County engineering department
testified regarding their most recent work at the intersection
prior to the August 24, 2009, accident. Foster had last mowed
near the intersection on June 24, and he testified that the stop
sign was present at that time. Rick DeBoer, who performs
general road maintenance for the County in the spring and
summer months, graded South 25th Street to Gage Road and
beyond on August 17. He testified that he automatically checks
for signs while grading, that he would have done so on that
day, and that he did not remember the stop sign being down.
If it had been down, DeBoer would have immediately called it
in or fixed it.
   An employee with the Lancaster County engineering depart-
ment maintains a computer database of all the signs owned by
Lancaster County which includes when the signs have been
replaced. The database also tracks why a sign is replaced,
including, for example, routine maintenance, installation of
a new sign, or the sign was stolen or vandalized. Each sign
is replaced every 10 years. Every year, an employee runs a
query through the database which results in a list of signs to be
replaced that year.
    Nebraska Advance Sheets
982	287 NEBRASKA REPORTS



                      (d) Additional District
                          Court Findings
   The district court found the County to be negligent. The
court stated that the County did not take reasonable steps to
ensure that the stop sign was in place and that a collision at
the intersection was foreseeable in the absence of a stop sign.
The court observed that there was no policy in place for rou-
tine or more frequent inspections during the months that the
intersection was rendered “blind” by mature corn. The court
noted that no records of traffic control device inspections were
kept by employees who routinely worked in the area, even
though employees kept records of what areas were mowed
and what roads were maintained, and that there was no record
of the route taken or observations made during inclement-
weather inspections.
   The district court found that the County would have discov-
ered the stop sign was missing had it carried out a reasonable
inspection and that the absence of a regular inspection, particu-
larly during the high-risk time of year, was not reasonable. The
court further found that “the inspections which were conducted
were not designed to assure a reasonable inspection of the traf-
fic control devices of the county. They were only conducted
haphazardly, in inclement weather, without a map of where
devices were located and without a search pattern that assured
complete inspection.”
   The district court considered the foreseeable nature of Aden’s
and Hall’s conduct. The court stated that it was foreseeable that
drivers on Gage Road and South 25th Street would not slow to
the extremely slow speeds necessary to avoid a collision and
that it was foreseeable that the risk of collision rises signifi-
cantly at the time of the year the collision occurred. The court
found the County liable, stating that Hall could have stopped at
the intersection and avoided the collision if the stop sign had
been in place.
                          (e) Discussion
   The district court correctly recognized that the claim against
the County based upon the missing stop sign was premised
                        Nebraska Advance Sheets
	                      HALL v. COUNTY OF LANCASTER	983
	                             Cite as 287 Neb. 969

upon the County’s failure to discover the absence of the sign
“within a reasonable time after actual or constructive notice”19
to the County. The court also correctly recognized that there
was no evidence of actual notice to the County. But the court
reasoned that constructive notice could be found in the absence
of a sign-inspection policy. We disagree.
   [10] In order to recover in a negligence action, a plaintiff
must show a legal duty owed by the defendant to the plaintiff,
a breach of such duty, causation, and damages.20 For purposes
of this opinion, we will assume, without deciding, that the
County breached a duty by failing to have a sign-inspection
policy. Once the County elected to erect a stop sign, it was
required to maintain it in conformance with the Manual on
Uniform Traffic Control Devices (Manual).21 With regard to
maintenance of traffic signs, the Manual provides in part:
         To assure adequate maintenance, a schedule for
      inspecting (both day and night), cleaning, and replac-
      ing signs should be established. Employees of highway,
      law enforcement, and other public agencies whose duties
      require that they travel on the roadways should be encour-
      aged to report any damaged, deteriorated, or obscured
      signs at the first opportunity.
The above provision is labeled as a “[g]uidance,” which the
Manual defines as “a statement of recommended, but not man-
datory, practice in typical situations, with deviations allowed if
engineering judgment or engineering study indicates the devia-
tion to be appropriate.” Notably, the Manual does not prescribe
a frequency for the inspection of signs.
   [11-13] Determination of causation is ordinarily a matter
for the trier of fact.22 By finding the County liable, the district
court determined that it was a proximate cause of the dam-
ages. A proximate cause is a cause that produces a result in a
natural and continuous sequence and without which the result

19	
      See § 13-910(9).
20	
      Blaser, supra note 17.
21	
      See § 60-6,121.
22	
      Brandon v. County of Richardson, 261 Neb. 636, 624 N.W.2d 604 (2001).
    Nebraska Advance Sheets
984	287 NEBRASKA REPORTS



would not have occurred.23 To establish proximate cause, the
plaintiff must meet three basic requirements: (1) Without the
negligent action, the injury would not have occurred, com-
monly known as the “but for” rule; (2) the injury was a natural
and probable result of the negligence; and (3) there was no
efficient intervening cause.24
   In actions brought pursuant to the Political Subdivisions
Tort Claims Act, this court has, on occasion, reversed the
judgment of the district court with respect to causation despite
the generally deferential standard of review. In Brandon v.
County of Richardson,25 the trial court found the victim to
be contribu­orily negligent, but we reversed that finding and
             t
stated that the record failed to show that the victim’s conduct
was a proximate cause. We reasoned, in part, that “[t]he record
does not show that had [the victim] kept law enforcement
accurately informed of her whereabouts or returned for the
second interview . . . the result would have been different.”26
And in Koncaba v. Scotts Bluff County,27 we reversed a trial
court’s judgment in the plaintiff’s favor after determining that
the record established, as a matter of law, that the plaintiff’s
decedent was contribu­orily negligent and that such negligence
                       t
was a proximate cause of the accident.
   On this record, no reasonable fact finder could conclude
that the County’s failure to have a sign-inspection policy was
a proximate cause of the accident. Hall and Norris had the
burden to show that if the County had established a proper
procedure for inspecting its signs, it would have discovered the
missing stop sign and replaced it before the accident occurred.
But there is no evidence to establish how long the stop sign
was missing or how frequently sign inspections should be con-
ducted under the circumstances. Thus, Hall and Norris cannot
establish that the sign was missing long enough that it would

23	
      Stacy v. Great Lakes Agri Mktg., 276 Neb. 236, 753 N.W.2d 785 (2008).
24	
      Radiology Servs. v. Hall, 279 Neb. 553, 780 N.W.2d 17 (2010).
25	
      Brandon, supra note 22.
26	
      Id. at 667-68, 624 N.W.2d at 627.
27	
      Koncaba v. Scotts Bluff County, 237 Neb. 37, 464 N.W.2d 764 (1991).
                       Nebraska Advance Sheets
	                     HALL v. COUNTY OF LANCASTER	985
	                            Cite as 287 Neb. 969

have been discovered pursuant to a sign-inspection procedure.
And because the Manual does not mandate any frequency of
inspection, liability in this case cannot be fairly attributed to
the County’s lack of a formal policy for sign inspections. As a
matter of law, the record fails to show that the County’s fail-
ure to have a sign-inspection policy was a proximate cause of
the accident.

                         (f) Resolution
   Because there was no evidence to establish that the County’s
failure to have a sign-inspection policy was a proximate cause
of the accident, we reverse the judgment of the district court
finding the County liable and apportioning fault to it. We
remand the cause to the district court to apportion the County’s
share of negligence between Hall and Norris.28

                      3. Hall’s Negligence
                            (a) Issue
   Norris argues that by failing to determine who had the right-
of-way at the intersection, the court failed to give proper con-
sideration as to whether Hall’s contributory negligence should
bar his recovery as a matter of law.

                     (b) Standard of Review
   In actions brought under the Political Subdivisions Tort
Claims Act, an appellate court will not disturb the factual find-
ings of the trial court unless they are clearly wrong.29
   [14] Where neither party requests that the trial court make
specific findings of fact and conclusions of law, if there is a
conflict in the evidence, the appellate court in reviewing the
judgment rendered will presume that the controverted facts
were decided in favor of the successful party, and the findings
will not be disturbed unless clearly wrong.30

28	
      See Downey v. Western Comm. College Area, 282 Neb. 970, 808 N.W.2d
      839 (2012).
29	
      Blaser, supra note 17.
30	
      C. Goodrich, Inc. v. Thies, 14 Neb. App. 170, 705 N.W.2d 451 (2005).
    Nebraska Advance Sheets
986	287 NEBRASKA REPORTS



                     (c) Additional District
                         Court Findings
   The court found that “regardless which driver had the
right[-]of[-]way, both drivers were negligent for approaching
the intersection at a rate of speed that was too fast for the
circumstances.” The court further found that Aden’s negli-
gence was greater than that of Hall because Aden was familiar
with the intersection, knew the intersection was completely
blind, and believed traffic from the north was not required
to stop, but entered the intersection at the maximum permis-
sible speed.

                         (d) Discussion
   Norris claims that the district court erred by failing to make
a finding regarding whether Hall or Aden had the right-of-way.
Norris argues that because the vehicles arrived at the intersec-
tion at approximately the same time, Aden had the right-of-
way. Hall argues that the statutory right-of-way is only one
factor to be used in evaluating a person’s conduct and that he
complied with the applicable standard of care. He directs us to
Hodgson v. Gladem,31 where we stated:
      The statutory right-of-way rule, if it is to be effective,
      must be accompanied by an observance by both parties
      of the rules applicable to the exercise of due care and in
      particular the duty to keep a lookout and make effective
      observations at a time when such observations can have
      an effect consonant with [the] underlying purpose of
      the rules.
   [15] The district court was not required to make a specific
factual finding regarding the statutory right-of-way. In the
absence of a request by a party for specific findings, a trial
court is not required to make detailed findings of fact and need
only make its findings generally for the prevailing party.32
Neither Norris nor any other party requested specific findings
by the district court. Accordingly, the court was not obligated

31	
      Hodgson v. Gladem, 187 Neb. 736, 741, 193 N.W.2d 779, 782 (1972).
32	
      Lesser v. Eagle Hills Homeowners’ Assn., 20 Neb. App. 423, 824 N.W.2d
      77 (2012). See Neb. Rev. Stat. § 25-1127 (Reissue 2008).
                        Nebraska Advance Sheets
	                      HALL v. COUNTY OF LANCASTER	987
	                             Cite as 287 Neb. 969

to make a specific determination regarding which driver had
the right-of-way.
                          (e) Resolution
   Because no party requested specific findings of fact by
the district court, we presume that any issue regarding the
statutory right-of-way rule was decided in Hall’s favor. But
because we remand for reallocation of the 20 percent of fault
initially allocated to the County, we do not know whether the
fault allocated to Norris will be equal to or greater than that
allocated to Hall.
                   4. Allocation of Damages
                           and Fault

                            (a) Issue
   Norris argues that the district court erred by failing to allo-
cate damages into economic and noneconomic damages and
by failing to allocate percentages of fault between Norris and
the County.
                    (b) Standard of Review
   [16] Because the purpose of comparative negligence is
to allow triers of fact to compare relative negligence and to
apportion damages on that basis, the determination of appor-
tionment is solely a matter for the fact finder, and its action in
this respect will not be disturbed on appeal if it is supported
by credible evidence and bears a reasonable relationship to the
respective elements of negligence proved at trial.33
                     (c) Additional District
                         Court Findings
   The district court awarded Hall $1,100,000 and identified
Hall’s medical expenses as totaling $357,335.86. The court
found the percentage of negligence of Norris and the County
to be 70 percent and the percentage of negligence of Hall to be
30 percent. After reducing the total damages by the 30 percent
which represented Hall’s contributory negligence, the court
entered judgment of $770,000 in Hall’s favor.

33	
      Connelly v. City of Omaha, 284 Neb. 131, 816 N.W.2d 742 (2012).
    Nebraska Advance Sheets
988	287 NEBRASKA REPORTS



                          (d) Discussion
   Norris’ argument is based on Neb. Rev. Stat. § 25-21,185.10
(Reissue 2008), which concerns the allocation of liability in
actions involving more than one defendant. Norris asserts that
the statute requires the district court to make specific rulings
on economic and noneconomic damages and requires a sepa-
rate judgment against each defendant for that defendant’s per-
centage of the noneconomic damages based on that defendant’s
percentage of fault.
   Our reversal of the judgment against the County undermines
Norris’ argument. Because we have determined that the County
is not liable for Hall’s injuries, the allocation between Norris
and the County is no longer an issue.
   But there is an issue of allocation remaining, which we
cannot resolve in this appeal. The district court allocated 50
percent of the negligence to Norris, 30 percent to Hall, and
20 percent to the County. Because we have determined that
the County was not liable for Hall’s damages, the 20 percent
of negligence allocated to it must be reallocated. But because
apportionment is solely a matter for the fact finder and will
be upheld except in very limited circumstances, we cannot
determine how the district court would have allocated the 20
percent as between Hall and Norris.34 We must remand the
cause in order for the district court to make this allocation in
the first instance.

                        (e) Resolution
   Because we have determined that the County is not liable for
Hall’s damages, the matter of allocation of damages between
the County and Norris is no longer an issue. But remand is
necessary to apportion the County’s share of the negligence as
between Hall and Norris. We remand the cause to the district
court for a reallocation of liability between Hall and Norris
based upon the existing record.


34	
      See Downey, supra note 28.
                        Nebraska Advance Sheets
	                      HALL v. COUNTY OF LANCASTER	989
	                             Cite as 287 Neb. 969

                  5. R emaining Assignments
                           of Error
  [17] Our resolution of this appeal makes it unnecessary to
consider the other assignments of error. An appellate court is
not obligated to engage in an analysis that is not necessary to
adjudicate the case and controversy before it.35

                         V. CONCLUSION
   We conclude that the County waived its claim that it was
entitled to immunity under the discretionary function excep-
tion, because it failed to identify sovereign immunity as an
issue for trial in the pretrial order. We reverse the judgment
of the district court finding the County liable, because there
is no evidence to establish that the County’s failure to have a
sign-inspection policy was a proximate cause of the accident.
Because the County is not liable, the matter of allocation of
damages between it and Norris is no longer an issue. But as to
the 20 percent of liability erroneously assessed to the County,
we cannot determine how the finder of fact would have allo-
cated such negligence between Hall and Norris. We remand
the cause to the district court for a reallocation, between Hall
and Norris based upon the existing record, of the 20 percent of
liability initially allocated to the County.
	Affirmed in part, and in part reversed and
	                   remanded for further proceedings.
   Wright, J., not participating.

35	
      Kerford Limestone Co. v. Nebraska Dept. of Rev., ante p. 653, ___ N.W.2d
      ___ (2014).
