for admissibility — such as relevance, necessity, reliability
and absence of bias. Bias remains a factor to be considered in
determining whether the potential helpfulness of the evidence is outweighed by the risk of the dangers associated
with that expert evidence.
(f) Expert evidence will rarely be excluded for bias; anything less
than clear unwillingness or inability to provide the court with
fair, objective and non-partisan evidence should not result in
exclusion. Rather, bias must be taken into account in the overall weighing of the costs and benefits of receiving the evidence.
Context is important. Both the extent of the expert’s alleged
bias and the nature of the proposed evidence are relevant.
The Trial Judge’s Decision
 The Crown proffered Kelly as an expert in a number of
areas related to accident reconstruction:
a. Collision Investigation and Analysis, including
i. Gouges, scrapes and scratches on roads,
ii. Motor Vehicle Collision Debris Fields,
iii. The Evaluation of Motor Vehicles involved in Collisions,
iv. The Interpretation of Tire Marks at Collision Scenes,
v. Speed Calculations and Distance Calculations,
vi. Co-Efficient of Friction Measurement Using the Vericom VC-3000
vii. Measurement of Collision Scenes, including the use of levels and
the Sokkia SRX5 Total Station;
b. The Interpretation of Airbag Control Module Data, alternatively known
as Restraint Control Module Data or Event Data Recorders; and
c. Perception Reaction time.
 The trial judge restricted the scope of Kelly’s opinion evidence, at paras. 195-96 of his admissibility reasons, to “analyses
and opinions based directly upon his personal observations, calculations and measurements as documented by his field notes and
in the photographs taken by him or at his direction”. The trial
judge stated, “[s]pecifically, I will admit portions of his ‘collision
investigation and analysis’, namely the identification, location,
and significance of gouges, scrapes, and scratches on roads, the
identification, location, and significance of motor vehicle collision
debris fields, and the evaluation of motor vehicles involved in collisions”. He also allowed Kelly to testify about speed calculations,