Unit 11 Assignment B (Distinction)

Zoebella Hollingsworth
Pearson level 3 national diploma in forensic and criminal investigations.
Unit 11 assignment B
P1: Explain why science is used in the investigation of the causes of road traffic
collisions.
Documentation comparative methods
 There are a couple of things police must do when investigating a traffic collision,
for example;
 The police should make note of the car's registration number, and when they get
to talk to the parties involved, they should also get their phone number and
address, so they can notify them about how the investigation is going.
 The police also need to make a note of the make, model and colour of the cars
involved in the accident; they need this to put in the police report.
 Police should note down the conditions of the road and what the weather was
like because this can help the police in determining other factors involved in
causing the accident.
 Photos should be taken of the car and the damage done to the vehicle, person,
or property.
 The angle the car is resting at should also be made note of because this can help
police in determining where the impact happened in the accident.
 Noting down all these things can help police when investigating the accident and
noting it all down will help with the persecution of the guilty party.
Naismith's rule (calculations based on a pedestrian's walking speed)
 Police can use Naismith's rule to calculate a pedestrian’s walking speed, they
could need to use this if someone was involved in a vehicle accident.
 Police could need to use this when trying to figure out what happened to the
person while they were walking from point A to point B and how they got
involved in the accident.
 The basic formular police would need to use is: 1 hour to walk 3 miles plus 30
minutes to ascend 1000ft.
 This rule can help the police to determine where the person was when the
accident occurred and how they got involved in the accident, determining how
the vehicle and the person collided, causing the accident.
Vehicle damage
 There is a couple of things police, or the people involved in the accident should
note down about damage to the vehicle:
 They should take photos of the damage done to the vehicles involved, this can
be used as concrete evidence in the investigation.
 They should make sure to check if there are any security cameras around the
area of the accident, this could help to locate any of the people involved in the
accident if they fled from the scene.
 Also, the police should talk to any of the people at the scene and get an idea of
what happened before and after the accident, this can help officers in
determining who was at fault for causing the accident.

, Personal injury
 The injuries need to be documented because they can help police officers to
determine what injuries the accident caused, and it can also help police officers
to gather information about the accident and if there was another person
involved in the accident. There are many injuries that can be sustained during a
road collision, some of the most common are:
 Brain and head injuries (these can be minimised by making sure to always wear
a seatbelt while in the car or driving, this will help prevent being tossed about in
the car during the accident.
 Whiplash (this usually only a couple of days but can be prevented by
remembering to put on a seatbelt while in the car and to be sure that the airbags
in the car have been checked in the cars MOT.
 Burns (these can be minimised by trying to make to pay complete attention to
the road while driving, these injuries may not be completely avoidable in an
accident.)
 Fractures and broken bones (these can be minimised by making sure to sit up
straight while driving and try not to be positioned too close to the airbag because
it could shoot out after the accident and cause more injuries.
Road marks and their measurements
 The investigating officers need to measure the length of the skid marks left by
the car after an accident, because this will help them determine how fast the car
could have been going at the time of the accident.
 When the skid (the drag due to the friction affecting the road surface) and the
efficiency of the brakes have been determined, then the officers can find out the
minimum speed the car was going when it started to skid.
 The police should also consider the state the road was when the accident
occurred because if the road were damaged, like the for example it had lots of
potholes the driver could possibly hit a pothole while driving and this could lead
to an accident.
Vehicle or human rest position
 Police can determine what factors had led up to the collision by examining where
the vehicle or person has been left after the accident.
 For example, if the car was found inside a ditch, then the police could determine
using the measurements of the skid mark and the final resting position of the
car, that the driver could have been driving too fast and hit black ice losing
control of the car and ending up in the ditch.
 This is very helpful for police as it will help them to determine whether anyone
else was involved in the accident or is it was just one person.
P3: Calculate velocity and use the coefficient of friction to determine the speed of
vehicles before a collision from collision scenarios.
Question 1:
 Car A pulls out in front of car B at a T junction.
 Car B collided with the side of car A.
 Car B leaves skid marks of 15 m from when the brakes are applied.
 Car B has a mass of 1000 kg, and the road has a coefficient of friction of µ = 1.1.