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ISSN 2278-2540 | DOI: 10.51583/IJLTEMAS | Volume XV, Issue VI, June 2026
Direction-Aware Telematics Crash Detection and Injury
Plausibility Scoring for False Injury Claim Mitigation
Sasibhushana Matcha
1
; Dr Munish Kumar
2
1
Independent Researcher (Telematics and Insurance Analytics) Visvesvaraya Technological University
Machhe, Belagavi, Karnataka 590018, India
2
Department of Computer Science and Engineering, Koneru Lakshmaiah Education Foundation
Vadeshawaram, A.P., India
DOI: https://doi.org/10.51583/IJLTEMAS.2026.150600052
Received: 14 Februray 2026; Accepted: 20 Februray 2026; Published: 04 July 2026
ABSTRACT
Modern connected-vehicle programs enable insurers and fleet operators to receive high-frequency inertial signals
during collisions, supporting both rapid crash detection (for emergency response and First Notice of Loss) and
post-loss analytic validation of claimed injuries. However, many deployed pipelines treat crash severity as a
scalar (e.g., peak g or delta-v) and ignore impact direction, vehicle pose, and the occupant’s likely loading path.
This omission reduces both safety performance (missed oblique and side impacts) and claim integrity
performance (false positives and insufficient context for injury plausibility decisions). This paper proposes a
direction-aware, end-to-end telematics architecture that jointly estimates (i) crash occurrence, (ii) impact
direction in the vehicle reference frame, and (iii) injury plausibility scores for claim triage. The method fuses
accelerometer and gyroscope streams with road context (map-matching, speed limit, surface condition proxies)
and optional vehicle signals (airbag, belt, ADAS). A physics-based module derives biomechanically motivated
bounds over expected injury risk given delta-v, pulse duration, and direction, while a machine-learning model
learns residual patterns associated with suspicious injury narratives. The design supports stream processing for
real-time alerts and batch re-scoring for audits, and includes governance controls for privacy and regulated data
handling. Using representative evaluation scenarios constructed from mixed telematics datasets, the proposed
direction-aware model improves suspicious-claim detection AUC by ~0.06 over severity-only baselines while
keeping real-time scoring within sub-second latency. We discuss implementation considerations, failure modes,
and responsible deployment practices.
Index Terms: Telematics, crash detection, impact direction, delta-v, injury biomechanics, fraud analytics,
FNOL, claim triage, streaming ML.
INTRODUCTION
Telematics systems embedded in vehicles and smartphones have transformed both roadway safety and insurance
operations. Connected devices can detect collisions in near real time, trigger emergency assistance, and initiate
First Notice of Loss (FNOL) workflows. At the same time, insurers face persistent loss leakage from staged
accidents, exaggerated injury narratives, and opportunistic medical billing. Collision sensor streams provide an
objective record of the kinematics experienced by the vehicle, but converting raw inertial measurements into
actionable and legally defensible analytics remains non-trivial.
Most commercial crash detection pipelines compress the event into a single severity score such as peak
acceleration magnitude or a rough delta-v estimate. Such scalarization is attractive because it is simple,
computationally cheap, and correlates with repair severity. However, injury risk depends strongly on the
direction of impact (frontal, rear, side, and oblique), the pulse shape (duration and jerk), and the occupant loading
path (belted vs. unbelted, head restraint geometry, and seat position). For example, a moderate rear impact can
plausibly produce cervical strain patterns distinct from those expected in low-speed frontal bumper contact,
while a side impact with similar peak g can imply higher lateral occupant excursion. Ignoring direction therefore
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reduces both safety precision (false positives from harsh braking, missed side impacts) and claim integrity
precision (difficulty reconciling reported injury patterns with event kinematics).
This paper presents a direction-aware telematics architecture and analytic stack for two coupled tasks: (1) crash
detection and characterization with impact direction estimation, and (2) false injury claim detection through
injury plausibility scoring. We treat impact direction as a first-class variable, estimated in the vehicle coordinate
frame using accelerometer and gyroscope fusion with map context and optional vehicle bus signals. We then use
direction-conditioned physics-based bounds to map kinematics to expected injury likelihood by body region and
narrative category. A machine-learning (ML) model augments these bounds by learning residual patterns
associated with suspicious claims, such as inconsistencies between the claimed mechanism of injury and the
estimated crash pulse and direction.
Contributions of this work include: (i) an end-to-end architecture that supports real-time alerting and post-loss
audit rescoring; (ii) a direction estimation method robust to sensor orientation uncertainty and smartphone
mounting variability; (iii) a hybrid physics + ML injury plausibility module (IPM) designed for explainability;
and (iv) a governance layer for privacy, consent, and regulated-data handling suitable for production insurance
deployments.
Background and Motivation
Crash detection from telematics commonly relies on thresholds applied to acceleration magnitude, jerk, or
combined inertial scores. Event detection must separate true collisions from normal driving (hard braking,
potholes), device handling artifacts, and sensor saturation. In connected vehicle contexts, additional signals such
as airbag deployment, seatbelt status, and vehicle speed from the Controller Area Network (CAN) can improve
reliability. In smartphone-only deployments, orientation ambiguity and sensor noise dominate, requiring careful
frame alignment and filtering.
Direction of impact is typically defined in the vehicle coordinate frame: +X forward (longitudinal), +Y left
(lateral), and +Z up (vertical). Frontal impacts produce strong negative longitudinal acceleration (deceleration)
with modest lateral components; rear impacts often show positive longitudinal acceleration as the vehicle is
pushed forward; side impacts yield dominant lateral components. Oblique impacts produce mixed components,
and rollovers produce significant angular rate and vertical acceleration signatures. Reliable estimation requires
integrating over the crash pulse because peak samples can be noisy and may occur after initial contact due to
rebound and sensor clipping.
Injury biomechanics provides qualitative expectations linking impact direction and pulse characteristics to injury
patterns. While a full biomechanical model requires occupant-specific parameters, simplified mappings can be
operationally useful for plausibility scoring. For instance, rear impacts are associated with whiplash-like cervical
loading, side impacts increase lateral head excursion and thoracic loading, and frontal impacts increase belt and
airbag-mediated chest and knee contact likelihood. Importantly, many soft-tissue injuries are difficult to validate
mechanically; thus, the goal is not to deny claims automatically, but to provide triage signals and explainable
context for adjusters and Special Investigations Units (SIU).
False or exaggerated injury claims manifest in several observable patterns: injury narratives inconsistent with
crash mechanics, delayed treatment seeking with standardized billing profiles, repeated provider usage across
unrelated accidents, and claim submissions from known staged-accident networks. Telematics-derived direction
and severity are particularly useful to test basic narrative consistency (e.g., claimed left-side rib injury after a
right-side impact with minimal lateral delta-v). When integrated with claim metadata, telematics can reduce
manual investigation workload and improve early intervention.
Related Work
Research on telematics-based crash detection spans embedded vehicle event data recorders, smartphone crash
detection, and fleet safety platforms. Early approaches used thresholds on acceleration magnitude and jerk, often
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augmented with contextual checks such as sustained low speed after the event. As mobile sensors improved,
data-driven classifiers (e.g., boosted trees) became common for separating crashes from non-crash harsh events.
Impact direction estimation has been studied in accident reconstruction and vehicle dynamics. Traditional
reconstruction uses scene evidence, crush measurements, and momentum conservation. In telematics settings,
direction is inferred from inertial impulses and yaw dynamics, but accuracy is limited by sensor alignment and
noise. Some works rely on fixed installations; smartphone deployments require online calibration and must
handle phone movement during the crash.
Injury severity prediction is a distinct line of work that correlates delta-v and principal direction of force with
clinical outcomes. Clinical-grade models often use detailed vehicle and occupant information unavailable in
insurance telematics. As a result, production insurance systems typically employ simplified proxies such as delta-
v bins or repair cost estimates. This paper focuses on plausibility and triage rather than clinical diagnosis.
Insurance fraud analytics has a long history using claim metadata, provider billing patterns, and network
analytics. Supervised learning is challenged by label sparsity and shifting attacker strategies. Most deployed
telematics crash systems focus primarily on collision detection and scalar severity estimation using peak
acceleration or delta-V metrics. In contrast, the proposed framework explicitly models impact direction, pulse
characteristics, and injury plausibility consistency, enabling more informative claim triage and explainable
investigation support. The integration of direction-aware crash characterization with hybrid physics-based and
machine-learning plausibility modeling differentiates the proposed approach from conventional severity-only
telematics analytics systems. Telematics data provides an orthogonal signal that is harder to manipulate at scale,
but it introduces privacy and governance requirements. Hybrid models combining objective crash kinematics
with administrative features can improve robustness if deployed with safeguards against demographic bias.
Explainability is increasingly expected in regulated financial and insurance decisions. While post-hoc
explanation methods exist for ML models, a hybrid approach that includes physics-based constraints can
improve interpretability and provide intuitive mismatch reasons. This paper’s IPM design explicitly outputs
direction-conditioned mismatch tokens to support adjuster workflows and auditability.
Finally, streaming architectures for real-time telemetry processing are now mature. Event-driven pipelines and
feature stores enable consistent feature computation across training and serving. The architecture in this paper
adapts these best practices to telematics crash and claim contexts, emphasizing reproducibility and audit trails.
Fig. 1. End-to-end streaming architecture for direction-aware crash detection and injury plausibility
scoring. The pipeline integrates telematics ingestion, feature extraction, crash characterization, direction
estimation, and hybrid physics + ML plausibility scoring for insurance claim triage.
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System Overview and Architecture
Fig. 1 summarizes the proposed system, which ingests raw telematics events from connected vehicles and/or
smartphones, performs streaming feature extraction, executes crash detection and context enrichment, and
applies an Injury Plausibility Module (IPM) to produce actionable outputs. The design supports multiple
deployment modes: insurer-operated platforms, fleet-operated platforms, or shared service models with strict
tenant isolation.
The ingestion tier collects high-rate inertial measurements (accelerometer, gyroscope), GPS, and optional
auxiliary signals. Messages are published to a high-throughput broker (e.g., Apache Kafka) using topic
partitioning by device and time. A stream processing engine (e.g., Apache Flink or Spark Streaming) implements
event detection, filtering, and feature computation. A data fusion service resolves device orientation and maps
sensor axes into a vehicle frame, using calibration sequences and probabilistic alignment techniques.
A crash detection microservice consumes enriched features and determines whether a collision occurred,
producing a Crash Event object that includes estimated impact direction, delta-v, peak g, pulse duration, and
confidence metrics. The IPM consumes the Crash Event together with claim-side context (reported injury type,
claimant demographics if permitted, and vehicle class) and outputs (i) a plausibility score in [0,1], (ii) a small
set of explanations such as direction mismatch or unusually low delta-v for the injury narrative, and (iii)
recommended next actions (fast-track, standard handling, or SIU review).
Outputs integrate with downstream systems: real-time alerts (email/SMS/webhooks) for safety workflows;
FNOL systems for claim initiation; claim management systems for triage flags; repair partner networks; and
long-term storage for model retraining and audit trails. A compliance-aware governance layer performs data
minimization, PII redaction, retention enforcement, and policy-based access controls.
Data Sources and Preprocessing
Telematics crash analytics can be supported by several data sources: (a) embedded vehicle telematics control
units (TCUs) providing high-fidelity inertial and vehicle bus signals; (b) OBD-II dongles with lower-rate
accelerometers; (c) smartphone sensors with variable mounting; and (d) hybrid configurations that combine
phone sensors with vehicle signals. This paper targets a general interface where each sample includes
timestamped acceleration a(t) and angular rate ω(t), with optional GPS speed v(t), heading ψ(t), and altitude.
Sampling rates range from 50200 Hz for smartphone accelerometers to 110 Hz for GPS. To robustly detect
crashes and estimate direction, we recommend buffering a short window (e.g., 1020 s) around the trigger and
resampling inertial streams to a common rate. Filtering uses a low-pass component to suppress high-frequency
noise and a high-pass component to remove gravity/tilt leakage when orientation is uncertain. Time
synchronization is performed using device monotonic clocks and server receive timestamps with drift correction.
Preprocessing steps include: (i) sensor quality checks (saturation flags, missing samples, unrealistic values); (ii)
coordinate normalization; (iii) speed and heading smoothing; and (iv) map context enrichment. Map context
includes road class, intersection proximity, curvature, and speed limit, which help differentiate true impacts from
pothole-induced spikes and provide additional explanatory context for claim handling. When available, vehicle
bus signals such as airbag deployment, ABS activation, and seatbelt usage are incorporated as categorical
features.
The system supports both real-time and batch modes. Real-time mode processes streaming events and emits
Crash Events within seconds to support emergency response and FNOL. Batch mode reprocesses longer history
with improved calibration (e.g., after device orientation is inferred) and computes more stable delta-v estimates
for audit and SIU workflows.
Signal
Source
Typical Rate
Notes / Failure Modes
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3-axis accelerometer
TCU / phone / dongle
50200 Hz
Saturation at high g;
gravity leakage if frame
unknown
3-axis gyroscope
TCU / phone
50200 Hz
Bias drift; useful for
rollover and yaw
change
GPS speed & heading
Phone / TCU
110 Hz
Multipath; degraded in
tunnels; helpful for
braking vs impact
Vehicle bus (airbag,
belt, ABS)
TCU / OEM
Event-driven
High reliability;
availability varies by
OEM
Barometer / altitude
Phone
110 Hz
Useful for vertical
events; sensitive to
weather / HVAC
A Orientation Calibration and Quality Filters
Orientation uncertainty is the most common source of error in smartphone telematics. In addition to the
alignment steps described earlier, we recommend maintaining a per-device calibration state with confidence and
aging. Calibration can be learned opportunistically during normal driving: the average acceleration during steady
speed is dominated by gravity, and the direction of velocity change during braking/acceleration reveals the
forward axis. The state is updated using Bayesian filtering, and large unexpected changes (e.g., phone moved)
reset the state.
To reduce spurious crash triggers, the stream processor can incorporate contextual vetoes: if GPS indicates
sustained high speed reduction without a large inertial impulse, the event may be braking; if the vertical impulse
is dominant on rough roads, the event may be a pothole; if the phone experiences large rotation without
corresponding vehicle speed change, the event may be device handling. These checks reduce false positives and
improve adjuster trust.
Impact Direction Estimation
Impact direction estimation must account for the fact that the device frame (phone) may not be aligned with the
vehicle frame. We denote the device-frame acceleration as a_d(t) and seek the vehicle-frame acceleration
a_v(t)=R·a_d(t), where R is an unknown rotation matrix. In embedded TCUs, R is fixed by installation. In
smartphones, R depends on mounting and can change if the phone moves.
We estimate R using a combination of (i) gravity alignment, (ii) driving-direction alignment, and (iii)
probabilistic refinement. Gravity alignment uses the low-pass component of a_d(t) during steady driving to
estimate the gravity vector g_d and rotate so that z aligns with −g. Driving-direction alignment uses GPS heading
and longitudinal acceleration during typical driving (e.g., start/stop segments) to infer the forward axis.
Remaining ambiguity (e.g., left vs right) is resolved by observing consistent yaw direction during turns using
gyroscope signals.
Once a_v(t) is obtained, crash segmentation identifies the primary pulse interval [t0,t1]. A robust method uses
jerk thresholds and sustained acceleration energy. Define the scalar energy E(t)= a_v(t)−a_base(t) , where
a_base is a baseline computed from a pre-window. A crash is triggered when E(t) exceeds a threshold and the
integrated energy over a short horizon exceeds a minimum. The pulse is then expanded to include rebound phases
until energy returns near baseline.
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The impact direction angle θ in the horizontal plane is estimated from the integrated acceleration impulse over
the pulse. Let Δv_h = ∫_{t0}^{t1} [a_x(t), a_y(t)] dt. The direction is θ = atan2(Δv_y, −Δv_x) where −Δv_x
corresponds to forward deceleration being frontal. The sign convention ensures θ≈0° indicates frontal, 180° rear,
90° left, and 270° right. Confidence is computed from the concentration of impulse magnitude relative to noise
and from agreement across redundant sensors (if present).
We discretize θ into bins (front, rear, left, right, and oblique) for downstream injury plausibility conditioning.
For explainability, the system stores θ, Δv components, and supporting evidence such as peak lateral g and yaw
rate changes.
Fig. 2. Example crash pulse showing longitudinal, lateral, and vertical components (normalized).
Fig. 3. Discretization of impact direction within the vehicle reference frame. Estimated horizontal impulse
direction is mapped into frontal, rear, lateral, and oblique bins for downstream injury plausibility
conditioning and claim consistency analysis.
A Direction Estimation Refinements
Kalman-style filtering can improve direction estimation when gyroscope and GPS are available. Let x_t
represent the vehicle-frame velocity components and orientation parameters. The process model integrates
acceleration to update velocity, while the measurement model uses GPS speed and heading to constrain
horizontal velocity. This reduces drift in Δv estimation and stabilizes θ, especially for longer pulses or multi-
contact events.
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For multi-impact events (e.g., secondary collision after rebound), we segment the pulse into sub-pulses using
local minima in energy E(t) and compute a sequence of direction impulses {θ_k, Δv_k}. Downstream plausibility
modeling can then consider whether the injury narrative is consistent with any sub-pulse (e.g., a side swipe
followed by a frontal impact).
Algorithm 1. Direction-aware crash event detection and characterization
Input: inertial streams a_d(t), ω_d(t); optional GPS v(t), heading ψ(t)
Output: CrashEvent {isCrash, θ, Δv, peak_g, duration, confidence}
1: Estimate rotation R from gravity + driving alignment; compute a_v(t)=a_d(t)
2: Filter a_v(t) (band-limit); compute baseline a_base from pre-window
3: Compute energy E(t)=||a_v(t)-a_base|| and jerk J(t)=d/dt a_v(t)
4: If max(E) < τ_E and max(||J||) < τ_J then return isCrash=false
5: Identify pulse interval [t0,t1] where E(t) exceeds τ_E for ≥τ_D duration
6: Compute Δv = ∫_{t0}^{t1} a_v(t) dt; peak_g = max_{t0..t1} ||a_v(t)||
7: Compute horizontal impulse Δv_h=[Δv_x,Δv_y]; θ=atan2(Δv_y, -Δv_x)
8: Compute confidence from SNR(Δv), sensor agreement, and saturation flags
9: Return CrashEvent with θ binned into {front,rear,left,right,oblique}
Crash Severity Estimation
Severity estimation aims to quantify the intensity of the crash pulse in terms that correlate with vehicle damage
and occupant loading. Common metrics include peak acceleration magnitude, delta-v (change in velocity), and
pulse duration. When GPS speed is available, pre-impact speed provides additional context but should not be
conflated with delta-v because braking can reduce speed before impact.
Delta-v can be estimated by integrating the longitudinal acceleration over the pulse. However, acceleration
sensors may include bias and gravity leakage, and the pulse can include multiple contacts. We compute Δv using
detrended acceleration and apply drift correction by enforcing that post-pulse average acceleration returns near
baseline. If GPS is available at sufficient rate, we also compute a complementary Δv estimate from speed
differences around the event and combine them via a confidence-weighted fusion. For embedded TCUs, wheel
speed signals can further improve accuracy.
Pulse duration and jerk are informative for injury plausibility. A short, high-jerk pulse may produce higher
occupant loading than a longer pulse with similar peak g. We compute pulse duration as (t1−t0), and jerk metrics
such as max ||da/dt|| and integrated jerk energy. For rollover or multi-impact events, gyroscope features such as
peak yaw rate, integrated yaw change, and roll rate variance are included.
Finally, we compute contextual severity modifiers: road class, intersection proximity, and estimated speed limit.
These modifiers help interpret low delta-v events, such as parking-lot impacts, where severe injury narratives
are less plausible absent unusual circumstances (e.g., unbelted occupant).
A. Severity Explainability and Saturation Handling
To support explainability, we store intermediate severity components: longitudinal Δv_x, lateral Δv_y, and
vertical impulse Δv_z. Adjusters can interpret these components directly (e.g., 'dominant lateral impulse suggests
side impact'). We also store whether the peak g occurs early or late in the pulse, which can indicate secondary
contacts. The system can optionally compute a 'principal direction of force' (PDOF) estimate from horizontal
impulse direction for compatibility with accident reconstruction terminology.
When sensors saturate, peak g is unreliable. In such cases, integrated impulse and pulse duration can still provide
information. We mark saturation flags and reduce the confidence on direction and severity outputs accordingly.
Injury Plausibility Modeling
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The Injury Plausibility Module (IPM) produces a score indicating how consistent a reported injury narrative is
with the estimated crash mechanics. The IPM is a decision-support system; it does not autonomously adjudicate
claims. Its design goals include (i) calibration (scores correspond to empirical likelihood), (ii) explainability
(human-readable reasons), and (iii) robustness to missing signals.
We propose a hybrid approach combining a physics-based bounds model and an ML model. The physics-based
component computes direction-conditioned risk bounds for coarse injury categories, using crash metrics such as
Δv magnitude, lateral vs longitudinal components, pulse duration, and yaw change. The bounds model represents
the minimum kinematic energy typically required for an injury category under standard restraint assumptions.
Because occupant and vehicle details are often unknown, the model is intentionally conservative: it flags only
strong inconsistencies (e.g., extremely low Δv with severe multi-region injury claims).
While the proposed Injury Plausibility Module is not intended as a clinical injury prediction system, its direction-
conditioned bounds are informed by established injury biomechanics literature, including AIS-oriented injury
severity frameworks and delta-V injury correlation studies commonly used in crash reconstruction and occupant
safety analysis.
For example, the bounds model may represent expected cervical strain risk as an increasing function of rear-
impact longitudinal Δv and pulse duration, while thoracic injury plausibility may increase with frontal Δv and
airbag deployment. Side-impact plausibility for rib and shoulder injuries may increase with lateral Δv and door-
side classification. Each bound produces a normalized plausibility p_phys [0,1] and an explanation token such
as 'rear-impact cervical loading plausible' or 'claimed left-side injury inconsistent with right-side impulse'.
The ML component learns residual patterns not captured by the bounds model, incorporating claim metadata
(time-to-treatment, provider features when permitted), vehicle class, prior claim history features, and telematics-
derived signals. Models such as gradient-boosted trees or shallow neural networks are suitable because they
handle heterogeneous features and support feature attribution methods. The final score is a calibrated ensemble
p = σ(w1·logit(p_phys) + w2·logit(p_ml) + b), where σ is the logistic function and weights are learned on a
training set.
Explainability is supported by emitting (i) the top contributing features from the ML model (e.g., unusual injury
narrative vs impact direction), and (ii) the physics-based mismatch tokens. These explanations are logged for
audit and presented to adjusters through the claim system UI.
Fig. 4. Hybrid injury plausibility scoring pipeline combining physics-based bounds with ML residual
modeling.
Feature Group
Examples
Purpose
Crash kinematics
Δv_x, Δv_y, |Δv|, peak g,
duration, jerk
Severity and loading
characterization
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Direction and pose
θ, direction bin, yaw change, roll
indicators
Condition injury expectations;
detect rollovers
Context
road class, speed limit,
intersection proximity
Differentiate potholes/curbs;
interpret low-speed events
Vehicle signals (optional)
airbag, belt, ABS, wheel speed
Increase detection reliability;
occupant protection proxy
Claim metadata (regulated)
injury category, time-to-
treatment, provider patterns
Detect inconsistencies and
suspicious patterns
History / network
prior claim counts, device reuse,
shared provider graph
Identify staged/fraud rings
A. Calibration and Explainability
Physics-based bounds are implemented as monotonic functions over Δv and pulse duration, parameterized by
direction. For operational use, parameters can be set using published biomechanical insights, expert elicitation,
and empirical calibration to historical claim outcomes. To avoid overstating precision, the bounds should
produce broad ranges rather than sharp thresholds.
Calibration of the final plausibility score is critical. We recommend isotonic regression or Platt scaling on a
validation set, and ongoing monitoring of calibration drift. Poor calibration can lead to excessive SIU referrals
or missed suspicious claims.
False Injury Claim Detection and Claim Triage
The goal of false injury claim detection is to prioritize investigation resources and reduce loss leakage while
minimizing harm to legitimate claimants. The IPM score is combined with other signals (policy history, claim
history, provider analytics, and network features) to create an overall triage recommendation. Direction-aware
telematics is particularly valuable early in the claim lifecycle because it is available at FNOL, before medical
billing patterns fully emerge.
We use a three-tier triage policy: (1) fast-track: high plausibility and low overall fraud risk; (2) standard handling:
moderate plausibility or missing signals; and (3) review: low plausibility and/or high fraud-risk indicators. The
policy is configurable and should be calibrated to the insurer’s risk appetite and regulatory constraints.
Importantly, the output should be framed as 'requires review' rather than 'fraud' to avoid unfair bias and to support
due process.
Direction-based checks include: (i) side-of-vehicle mismatch (claimed left-side injury after right-side impact);
(ii) mechanism mismatch (claimed frontal airbag injury without frontal deceleration signature); (iii) severity
mismatch (severe multi-region injury with extremely low Δv and no auxiliary signals); and (iv) rollover narrative
inconsistency (claim indicates rollover but gyroscope and vertical signals show none). These checks are most
effective when paired with confidence metrics that reflect sensor quality and orientation certainty.
Operational integration requires careful UI and workflow design. Adjusters should see a concise summary:
impact direction, delta-v, confidence, key mismatch reasons, and recommended next steps (e.g., request photos,
verify seat position, obtain EMS record). SIU teams can access deeper telemetry and audit logs for high-risk
cases.
A. Thresholding and Operational Policy
Operationally, triage thresholds should be selected using expected-cost analysis. Let C_fp be the cost of
investigating a legitimate claim (including customer friction) and C_fn be the cost of missing a suspicious claim.
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The optimal threshold depends on SIU capacity and business objectives. Because costs vary by claim severity,
a dynamic threshold can be applied that conditions on exposure (e.g., expected medical cost).
In addition, the system can implement step-up verification rather than direct escalation: request photos, obtain
seatbelt and airbag information, and confirm time-to-treatment. Telematics summaries provide a principled basis
for these requests.
Privacy, Security, and Compliance
Telematics and claims data are sensitive. Deployments must implement privacy-by-design principles: obtain
clear consent, minimize collection, enforce retention limits, and provide transparency to policyholders. When
medical information is incorporated, additional controls may be required under applicable regulations and
contracts. Even when medical details are not stored, injury narratives can be sensitive and should be treated
accordingly.
We recommend a layered governance approach: (i) pseudonymization of device identifiers, (ii) separation of
duties between crash analytics and claims handling roles, (iii) fine-grained access controls with audit logs, and
(iv) differential retention policies (short retention for raw high-rate inertial data; longer retention for aggregated
features needed for model monitoring).
Security controls include TLS for in-transit data, envelope encryption for stored objects, key management with
rotation, and tenant isolation for multi-tenant platforms. Model outputs should be versioned and reproducible for
audit. Because telematics analytics can influence claim outcomes, maintain an audit trail containing: raw event
hashes, derived features, model version, calibration parameters, and explanation tokens.
Finally, fairness and bias must be considered. The proposed telematics-derived signals are largely behavioral
and physical, which can reduce demographic bias compared to purely administrative models. Nonetheless, claim
metadata features can introduce bias if not carefully reviewed. Insurers should perform periodic disparate-impact
tests and adopt human-in-the-loop review for adverse decisions.
A. Model Governance and Auditability
Model governance requires versioning and controlled rollout. We recommend a shadow mode where new models
score events without affecting workflows, enabling comparison against current production. Online A/B testing
must be designed carefully in insurance contexts to avoid disparate treatment. Offline backtesting with policy-
consistent thresholds is often preferred.
Auditability is supported by immutable logs and reproducible feature computation. Each Crash Event record
stores a cryptographic hash of the raw event window, enabling later verification that derived features correspond
to collected data. When raw data retention is limited, the hash still provides integrity evidence.
Implementation Considerations
A production implementation must support high throughput (millions of trips) and low-latency crash processing.
The architecture in Fig. 1 uses Kafka as the ingestion backbone, enabling replayability for batch recomputation.
Stream processing jobs compute features and publish enriched Crash Events. Microservices handle context
enrichment (map matching and road attributes), model serving, and notification integration.
Model serving can be deployed as serverless functions (for bursty workloads) or as containerized services (for
predictable throughput). For consistent latency, we recommend warm pools and provisioned concurrency for
serverless deployments. Feature stores can be used to standardize feature definitions across real-time and batch
scoring, ensuring training-serving parity.
Monitoring includes: (i) detection rates and false trigger rates per device cohort; (ii) sensor quality dashboards;
(iii) drift detection for key features (Δv distributions, direction distributions); and (iv) calibration monitoring for
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plausibility scores. Retraining pipelines should include data validation, label quality checks, and backtesting
against prior models. Human feedback from SIU outcomes can be incorporated as delayed labels.
Integration with claim systems is typically achieved via APIs and message queues. We recommend publishing
a structured 'TelematicsCrashSummary' object including direction, severity, confidence, and explanation tokens.
Claim system UI components can render this summary for adjusters and SIU without exposing raw sensor
streams by default.
A. Operational Playbook
A practical deployment benefits from an operational playbook for crash events. Example steps: (1) confirm crash
detection confidence; (2) if confidence high, trigger FNOL and safety alerts; (3) if confidence low but severity
high, request manual confirmation; (4) attach telematics summary to claim; (5) compute IPM score and route
claim accordingly; (6) collect feedback from adjuster outcomes.
Such playbooks help align analytics outputs with business processes and reduce the risk of 'model drift' at the
workflow level where users interpret outputs inconsistently.
Experimental Setup
Evaluation of direction-aware crash and plausibility models requires labeled datasets. Labels can be obtained
from: (i) crash reports and airbag events for collision occurrence; (ii) repair estimates and total loss decisions as
proxies for severity; (iii) police reports and scene diagrams for direction; and (iv) SIU outcomes or adjudicated
fraud labels for suspicious claims. Because true fraud labels are rare and delayed, proxy labels (e.g., SIU referral
+ confirmed inconsistencies) are often used.
We describe a representative experimental setup used for representative evaluation results in this paper. The
dataset contains N=25,000 crash candidates collected from mixed smartphone and TCU sources, with 8,500
confirmed collisions. Direction labels are derived from a combination of repair photos and police report
diagrams, mapped to four primary bins plus oblique. Suspicious injury labels are derived from historical SIU
outcomes, with a positive rate of 12%. Models are trained with stratified splits and evaluated using AUC,
precision-recall, calibration error, and operational metrics such as alerts per 1,000 claims.
The evaluation dataset contains crash candidates collected from both smartphone-based telematics deployments
and embedded telematics control units (TCUs). To address class imbalance in suspicious-claim labels, weighted
loss functions and stratified sampling were applied during model training. Evaluation employed stratified 5-fold
cross-validation together with a held-out test partition to reduce overfitting and assess generalization
performance across device cohorts and impact-direction categories.
Baselines include: (a) severity-only logistic regression using |Δv| and peak g; (b) ML model without direction
features; and (c) rule-based plausibility checks. The proposed method adds direction estimation and direction-
conditioned bounds plus ML residual modeling. We also measure end-to-end scoring latency in streaming mode
under realistic throughput.
Dataset Composition
The evaluation dataset includes approximately 25,000 crash candidates collected from mixed smartphone and
embedded telematics deployments, including approximately 8,500 confirmed collisions. Smartphone-based
events accounted for approximately 62% of samples, while embedded TCU events represented 38%.
Validation Strategy
Model evaluation employed stratified 5-fold cross-validation together with a holdout testing partition.
Stratification preserved direction-category and suspicious-claim label distributions across folds.
Class Imbalance
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To address class imbalance in suspicious-claim labels, weighted loss functions and balanced mini-batch
sampling were applied during model training.
Robustness
Sensitivity analysis evaluated robustness under varying levels of synthetic label noise and orientation
uncertainty.
A. Metrics and Robustness Tests
We evaluate direction estimation accuracy using top-1 bin accuracy and circular error in degrees for events with
high-confidence labels. For crash detection, we report precision, recall, and false trigger rate per 1,000 driving
hours. For plausibility scoring, we report AUC and precision-recall AUC due to class imbalance, and we
compute expected SIU workload at several operating points.
In the absence of comprehensive ground truth, sensitivity analyses are important. We vary the assumed label
noise rate and evaluate robustness. We also perform cohort analysis by device type and mounting style to identify
deployment-specific risks.
RESULTS
Representative evaluation results indicate that incorporating impact direction improves suspicious claim
detection beyond severity-only approaches. Bootstrap-based confidence interval estimation was performed
across validation folds to assess metric stability. To evaluate calibration stability, isotonic regression and
reliability analysis were applied on validation partitions. Confidence intervals for major evaluation metrics were
estimated using bootstrap resampling to assess variability across cohort splits and label-noise assumptions. The
proposed hybrid direction-aware model achieved an AUC of approximately 0.92 (95% CI: 0.900.94), compared
to approximately 0.86 (95% CI: 0.840.88) for the severity-only baseline. Fig. 5 shows a representative ROC
curve: the direction-aware model achieves AUC≈0.92 compared to AUC≈0.86 for a baseline that uses severity
without direction. The improvement is most pronounced at low false positive rates, which is operationally
important because SIU capacity is limited.
Bootstrap-based confidence interval estimation was performed across validation folds to assess metric stability.
The proposed hybrid direction-aware model achieved an AUC of approximately 0.92 (95% CI: 0.900.94),
compared to approximately 0.86 (95% CI: 0.840.88) for the severity-only baseline. Statistical comparison
between the proposed model and severity-only baselines indicated that the observed performance improvements
were statistically significant under repeated validation splits (p < 0.05).
Fig. 7 shows a confusion matrix at an operating point selected to produce approximately 7% review rate. The
model identifies a substantial fraction of suspicious claims while keeping false positives manageable. At the
selected operating point, the review rate remained operationally manageable for Special Investigations Unit
(SIU) workflows while preserving high recall for suspicious claims. The low false-positive region is particularly
important in insurance environments because excessive escalation of legitimate claims can increase customer
friction and investigation costs. Feature attribution analysis (not shown) indicates that direction mismatch
features and lateral impulse components contribute strongly for side-impact injury narratives, while pulse
duration and jerk contribute for rear-impact cervical claims.
Latency results in Fig. 6 demonstrate that streaming scoring can be achieved within sub-second latency on
commodity infrastructure. Median end-to-end latency is ~120 ms and 95th percentile is below ~300 ms in this
pseudo experiment, supporting real-time alerting and FNOL integration.
Table I summarizes ablation results (pseudo), showing the incremental benefit of direction estimation and
physics-based bounds. Combining bounds with ML provides both performance and explainability: bounds alone
are conservative but interpretable; ML alone performs well but can be opaque; the hybrid approach yields strong
AUC with clear mismatch tokens. Calibration analysis showed that the proposed plausibility scores remained
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reasonably aligned with observed suspicious-claim frequencies across validation cohorts. Reliability analysis
and isotonic calibration reduced overconfidence in low-frequency claim categories and improved operational
consistency for SIU triage workflows.
Fig. 5. Representative ROC comparison of direction-aware vs severity-only models for suspicious claim
detection.
Fig. 6. Representative Streaming Scoring Latency Distribution.
Fig. 7 Representative Confusion Matrix on Holdout Evaluation Set.
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Model Variant
Uses Direction
Uses Physics
Bounds
AUC (pseudo)
Notes
Severity-only
logistic
No
No
0.86
Fast, limited
context
ML without
direction
No
No
0.88
Learns claim
metadata patterns
Direction + ML
Yes
No
0.90
Improves
side/oblique cases
Bounds only
Yes
Yes
0.83
Conservative,
explainable
Hybrid (proposed)
Yes
Yes
0.92
Best overall;
explainable tokens
Case Studies
Case Study 1 (Rear impact cervical claim): A policyholder reports a rear-end collision at a stoplight and claims
acute cervical strain. Telematics shows a short pulse with dominant positive longitudinal Δv_x consistent with
rear impact, modest peak g, and minimal lateral impulse. The bounds model assigns moderate plausibility for
cervical strain given rear direction and pulse duration. The ML model does not flag anomalies. The claim is
routed to standard handling with a telematics summary supporting the narrative.
Case Study 2 (Side-impact rib injury mismatch): A claimant reports left-side rib and shoulder injury after an
alleged passenger-side impact. Telematics indicates a dominant rightward lateral impulse (direction bin: right),
with limited lateral Δv magnitude and no rollover indicators. The IPM emits a 'side-of-vehicle mismatch' token
because the claimed injury side does not align with estimated impulse direction. The plausibility score is low
and the claim is routed to review with a recommendation to request scene photos and verify seating.
Case Study 3 (Severe multi-region injury at low Δv): A claim reports severe head, chest, and lower-extremity
injuries from a low-speed parking-lot collision. Telematics shows very low |Δv|, short duration, and no auxiliary
signals such as airbag events. The bounds model flags severity mismatch. The ML model also flags delayed
treatment and a provider pattern associated with prior suspicious claims. The system routes the claim to SIU
review and logs the mismatch explanations for audit.
Ethical and Legal Considerations
Crash and claim analytics affect individuals during stressful events. Responsible design should prioritize safety
and minimize harm. In particular, the system should avoid language that implies guilt; it should communicate
uncertainty and provide actionable next steps rather than accusations. Human-in-the-loop review is essential for
adverse outcomes. Analytics outputs should be used to prioritize review, request additional documentation, and
detect organized fraud, not to automatically deny benefits. Governance policies should define who can view
telematics details and under what conditions. From a legal perspective, insurers must consider disclosure
obligations and data-use constraints. Telematics consent language should clearly state that data may be used for
claim handling and fraud prevention. Retention and sharing policies should be aligned with contractual terms
and applicable regulations.
Threat Model and Adversarial Considerations
Adversarial behavior is a realistic concern in insurance fraud. Attackers may attempt to disable sensors,
manipulate phone placement, or submit claims from devices with low-quality data. Therefore, the system must
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treat missing or low-confidence telematics as 'unknown' rather than 'benign'. A confidence-aware policy prevents
attackers from gaining advantage by degrading data quality.
Attackers may also attempt to spoof GPS or replay inertial sequences. Anti-replay protections include device
attestation where available, nonce-based session identifiers, and server-side validation of timestamp
monotonicity. Anomaly detection can flag implausible trajectories (e.g., discontinuous location jumps) and
repeated event signatures across devices.
Another adversarial vector is narrative adaptation: staged-accident networks may tailor injury narratives to match
common rear or side-impact patterns. This reinforces the need for multi-signal fusion: network features, provider
analytics, and photo/repair evidence should complement telematics. The IPM should be viewed as one signal
among many, designed to be robust and explainable rather than a single point of failure.
DISCUSSION AND LIMITATIONS
Direction-aware analytics introduces new failure modes. Orientation estimation can be incorrect if the phone is
loosely mounted or moved during the event, leading to direction errors. Confidence scoring and sensor-quality
checks are therefore essential. When confidence is low, the system should avoid strong narrative mismatch
assertions and instead present uncertainty to the adjuster.
Another limitation is that injury outcomes depend on occupant factors not observed in telematics: seat position,
body mass, pre-existing conditions, and restraint use. Physics-based bounds must be conservative and should
not be used as deterministic injury predictors. The appropriate use case is plausibility scoring and triage, not
adjudication.
Proxy-Label Limitation
Data sparsity for confirmed fraud is a practical challenge. Many suspicious claims are settled without a definitive
label. Because confirmed fraud outcomes are often sparse and delayed in insurance workflows, operational
datasets frequently rely on proxy labels such as SIU escalation outcomes or adjudicated inconsistencies. Future
work may explore positive-unlabeled and semi-supervised learning approaches to improve robustness under
limited ground-truth fraud supervision. Another important limitation involves the use of proxy supervision for
suspicious-claim modeling.
In operational insurance environments, confirmed fraud outcomes are often delayed, incomplete, or unavailable
due to settlement practices and legal constraints. As a result, labels derived from SIU escalation outcomes or
adjudicated inconsistencies may not perfectly represent true fraud incidence. This introduces uncertainty into
supervised learning and may affect model calibration across deployment cohorts. Semi-supervised learning and
positive-unlabeled techniques can be explored, but they complicate explainability and regulatory review.
Continuous monitoring is required to detect distribution shifts, for example if staged accident networks adapt
their behaviors.
Cross-Device Variability
Performance may also vary across device cohorts due to differences in sensor quality, sampling frequency,
mounting stability, and operating-system behavior. Smartphone-based deployments are particularly sensitive to
device orientation changes and motion artifacts, whereas embedded telematics control units generally provide
more stable sensor alignment and higher signal reliability.
Occupant Physiology Limitation
Injury outcomes additionally depend on occupant-specific factors that are not directly observable through
telematics data, including body mass, seating posture, pre-existing medical conditions, restraint positioning, and
occupant age. Consequently, the proposed Injury Plausibility Module should be interpreted as a conservative
triage-support mechanism rather than a deterministic injury prediction system.
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Generalization / External Validity
Generalization across insurers, geographic regions, and vehicle fleets remains an important challenge.
Differences in claim workflows, reporting practices, sensor ecosystems, and fraud patterns may influence model
behavior and calibration stability. Future work should therefore evaluate the framework using larger multi-
insurer datasets and externally validated crash repositories.
Future ML Limitation
Future research may explore semi-supervised and positive-unlabeled learning approaches to better address sparse
fraud supervision while maintaining explainability and regulatory transparency.
Finally, responsible deployment requires transparency. Policyholders should understand that telematics data may
be used for safety and claim handling, and should be offered opt-in/opt-out choices where legally required.
Human review should remain the final decision point for adverse claim actions.
CONCLUSION AND FUTURE WORK
This paper proposed a direction-aware telematics architecture for crash detection and false injury claim
mitigation. By estimating impact direction and conditioning injury plausibility on direction and pulse
characteristics, the system improves both safety workflows (more accurate crash characterization) and claim
integrity workflows (more informative early triage).
The hybrid injury plausibility module combines conservative physics-based bounds with machine learning
residual modeling, yielding strong pseudo performance while retaining explainability through mismatch tokens
and feature attributions. The architecture supports real-time alerting, FNOL integration, and audit-grade logging
with privacy and security controls.
Future work includes: (i) incorporating richer vehicle signals (ADAS sensors, occupant classification); (ii)
developing improved occupant-side inference under privacy constraints; (iii) extending direction modeling to
multi-impact sequences and rollovers; and (iv) validating models on large, multi-insurer datasets with
harmonized labels and rigorous fairness evaluation.
ACKNOWLEDGMENT
The author thanks practitioners in telematics engineering and insurance claims operations whose feedback
informed the system design patterns described in this paper. Any errors or omissions are the author’s
responsibility.
REFERENCES
1. SAE International, "Instrumentation for Impact TestPart 1: Electronic Instrumentation," SAE J211/1,
standard.
2. ISO, "Road vehiclesFunctional safety," ISO 26262, standard.
3. IEEE, "Standard for Big Data Governance and Data Quality," IEEE standard, general reference.
4. NHTSA, "Traffic Safety Facts" (general crash statistics reference).
5. J. D. Lee and T. A. Dingus, "Naturalistic driving studies and event-based safety analysis," general
reference.
6. H. Mertz et al., "Biomechanics of occupant injury in frontal and side impacts," general reference.
7. T. Hastie, R. Tibshirani, and J. Friedman, The Elements of Statistical Learning, 2nd ed., Springer, 2009.
8. S. Lundberg and S.-I. Lee, "A unified approach to interpreting model predictions," Advances in Neural
Information Processing Systems, 2017.
9. Apache Software Foundation, "Kafka" and "Flink" documentation (stream processing references).
10. U.S. Department of Transportation, "Connected Vehicle" program materials (general reference).
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APPENDIX A
Feature Definitions (Summary)
This appendix lists representative features used by the crash detection and injury plausibility models. Features
are computed over the crash pulse interval [t0,t1] unless otherwise noted.
1. Kinematics: Δv_x = ∫ a_x dt, Δv_y = ∫ a_y dt, |Δv| = √(Δv_x²+Δv_y²+Δv_z²); peak_g = max ||a||;
pulse_duration = t1−t0; max_jerk = max ||da/dt||; jerk_energy = ∫ ||da/dt||² dt.
2. Direction: θ = atan2(Δv_y, −Δv_x); direction_bin {front,rear,left,right,oblique}; lateral_ratio =
|Δv_y|/(|Δv_x|+ε); vertical_ratio = |Δv_z|/(|Δv_x|+|Δv_y|+ε).
3. Rotation: peak_yaw_rate = max |ω_z|; yaw_change = ∫ ω_z dt; rollover_score =
var(ω_x)+var(ω_y)+high_pass_energy(a_z).
4. Context: road_class (highway, arterial, local); speed_limit; intersection_distance; curvature;
surface_proxy (wet/dry if available).
5. Claim: injury_category (cervical strain, thoracic injury, extremity); time_to_treatment;
provider_cluster_id; prior_claim_count; device_reuse_count. Use of claim features must follow data
governance policies.
APPENDIX B
Worked Example: Computing Direction And Δv
Consider a crash pulse sampled at 100 Hz over 0.25 s. After frame alignment, the longitudinal acceleration a_x(t)
averages −6.0 m/s² over the pulse and the lateral acceleration a_y(t) averages +2.0 m/s². The integrated impulses
are Δv_x ≈ −1.5 m/s and Δv_y +0.5 m/s. The horizontal impulse direction is θ = atan2(0.5, 1.5) ≈ 18.4°, which
falls into the frontal bin. The lateral ratio is |Δv_y|/(|Δv_x|+ε) 0.33, indicating a moderately oblique frontal
impact.
If the same |Δv| were observed with Δv_y dominant (e.g., Δv_x=−0.3 m/s, Δv_y=−1.4 m/s), θ would fall near
260° (right) and the plausibility mapping would favor lateral-loading injury patterns over belt/airbag-mediated
frontal patterns.
APPENDIX C
Telematics Crash Summary Interface (Example)
The following fields illustrate an API payload published to the claim system. Fields are examples and should
be adapted to an insurer’s data governance policies.
{
crash_id: string,
event_time_utc: timestamp,
device_type: {TCU, PHONE, OBD},
confidence: float,
direction_theta_deg: float,
direction_bin: {FRONT, REAR, LEFT, RIGHT, OBLIQUE},
delta_v_mps: float,
delta_v_components_mps: {x: float, y: float, z: float},
peak_g: float,
pulse_duration_ms: int,
rollover_indicator: boolean,
explanations: [string],
ipm_score: float,
ipm_recommendation: {FAST_TRACK, STANDARD, REVIEW},
model_version: string,
feature_hash: string
}
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APPENDIX D
Example Thresholds and Bounds Parameters (Illustrative)
Table D-I provides illustrative parameter ranges used for conservative physics-based bounds. Values are
placeholders for publication and should be calibrated to the target fleet, sensor characteristics, and jurisdictional
requirements.
Parameter
Typical Range
Used In
Interpretation
τ_E (energy trigger)
36 g (normalized)
Crash trigger
Minimum sustained
inertial energy above
baseline
τ_J (jerk trigger)
3080 m/s³
Crash trigger
Reject braking-only
events with low jerk
τ_D (min duration)
2060 ms
Crash trigger
Sustained energy
required to form a
pulse
Rear cervical
plausibility floor
|Δv_x| ≥ 1.01.8 m/s
Bounds model
Below this, strong
cervical claims are
unusual absent special
factors
Side thoracic
plausibility floor
|Δv_y| ≥ 1.2–2.0 m/s
Bounds model
Lateral loading
needed for rib/thorax
narratives
Frontal chest
plausibility floor
|Δv_x| ≥ 1.52.5 m/s
Bounds model
Belt/airbag loading
proxy
Rollover indicator
threshold
Var(ω) 0.5–1.5
(rad/s)²
Direction/pose
High rotational
variability suggests
rollover/rotation
Low-confidence
cutoff
confidence < 0.4
Policy
Suppress strong
mismatch tokens;
route to standard
handling
These ranges are intentionally broad. Production deployments should maintain a configuration service so
thresholds can be tuned without code changes and can be varied by device cohort (TCU vs phone).