TECHNOLOGY
Technology Tools Help Drive Higher
Accuracy of Crash Scene Documentation
By Bob Galvin, RS Galvin & Associates
For truly effective documentation of crash and crime scenes,
investigators in sheriff’s offices need not only solid forensic
training and skills, but powerful technology, too. At the core
of investigating and processing these scenes is careful documentation since it represents a permanent written record that will
show scene conditions and evidence. Ultimately, once a scene
is measured, a detailed 2D or 3D diagram is created that must
withstand scrutiny in the courtroom.
As sheriff’s offices still wrestle with tighter budgets, obtaining
the most current technology is difficult. In many cases, the total
station remains the standard measuring tool that is highly reliable and usually affordable, and which can be used with lowcost data collection software and scene diagramming programs.
Other measuring methods such as laser systems, laser scanners,
and photogrammetry also are solid documentation tools, yet
the total station is predominantly used since it can take fast and
very precise ground measurements.
Total Stations Used With Aerial Mapping
The Nye County, Nevada, Sheriff’s Office is one of the first
in the state to pursue technology for its mostly crash investi46 H Sheriff®
November/December 2012
gations. Leading this effort is Sheriff Tony DeMeo, who oversees 70 deputies covering his office’s sprawling northern and
southern commands of Nevada. He uses two Sokkia SET550RX
total stations, and the Crash Zone and Crime Zone diagramming software from The CAD Zone, Inc., which enables him to
produce two and three dimensional diagrams. Sheriff DeMeo
was able to purchase his two total stations, which he personally
specified after learning Sokkia was a frequently used brand in
crash investigations, and the diagramming software with PETT
funds or Payments Equal to Taxes paid to Nye County for the
Yucca Mountain Nuclear Waste Repository Project.
The Sokkia SET550RX total stations were chosen for several
valuable capabilities: enhanced environmental durability,
including extreme heat and cold, the finest powder dust, and the
hardest driving rain; measurement range of 1,310 feet; display
of crash scene measurement results within 1.7 to 4.2 seconds
under any circumstance; and a narrow red EDM (electronic
distance meter) beam for pinpoint reflectorless measurement.
The total stations and drawing software are used mostly for
serious injury and fatal accidents. Because of the severity and
scope of these scenes, Sheriff DeMeo often will overlay mapped
TECHNOLOGY
scenes on top of aerial images of them provided by Google
Earth. “We do this often because it is evidence that will be used
in court,” the sheriff said. “And people in court can see exactly
where an accident occurred.” Another benefit is that layers of
the scene can be created with The Crash Zone software and
pulled out for observation and analysis as needed. The layers
show specific sections or details of a crash scene.
Huge Time Savings
When Nye County Sheriff’s Office investigators map a
crash scene, the total stations plot evidence points as they are
captured. “This allows investigators to see immediately if a
scene was accurately plotted,” Sheriff DeMeo said.
By using the total stations, Sheriff DeMeo estimates scenes
are documented 60 to 70 percent faster compared to, say, using
a steel tape measure or measuring wheel. And, he adds, “We’re
giving the judge and jury a more realistic portrait of the scene
than we have in the past, and, with aerial photo overlays of a
scene, exactly where an event happened.”
According to Sgt. Mark Kimsey of the Traffic Homicide
Division of Hamilton County Sheriff’s Office in
Chattanooga, Tennessee, the public is demanding more
intensive crash investigations to learn why the rate of
crashes is rising, how they occur, and out of concern
for increased road safety. Sgt. Kimsey works with one
other sergeant and two investigators investigating
crashes. They mapped 100 crashes in 2011, 18 of which
involved fatalities.
Older Total Stations Still Going Strong
In this tight-money economy, aging technology tools
oftentimes must continue handling the rising number
of crash scene investigations. Which is why Sgt. Kimsey
still uses two older Topcon total stations, one ten-years
old and the other total station five years-old, and
equipped with prism poles. The total stations, used roughly 100
times a year and still going strong, are married with The CAD
Zone, Inc.’s Pocket Zone data collection software. The Pocket
Zone serves as both a data collector and a true CAD program. It
connects to many total stations and laser measurement systems,
which allows the user to accurately record all 3D point and line
data shot at the scene. “We wanted to be able to diagram a crash
right at the scene,” explains Sgt. Kimsey, “and then shoot our
points from a total station right into The Pocket Zone, which
will put it straight into our desktop diagramming program.”
As with Sheriff DeMeo, Sgt. Kimsey considers using a total
station a highly reliable method for scene documentation.
“It’s extremely rugged,” he said. “We’ve shot in all kinds of
weather—below freezing, 100 degrees, pouring rain, snow and
ice, and never had a problem collecting our data.”
Identifying Most Recent Evidence is Focus
Determining what evidence is relevant at a crash scene is
crucial to accurate documentation. That’s the opinion of Sgt.
Paul Wade, Supervisor of the Major Accident Reconstruction
Sheriff ® November/December 2012
H 47
TECHNOLOGY
Preserving Scene Evidence, Moving Traffic Are
Challenges
Team with the Orange County, California, Sheriff’s Office.
Mapping crashes at intersections can be especially tricky; due to
prior accidents, there can be substantial evidence in the street
that was brought there by other vehicles at other times. “Some
of the difficulty you have when you go out there is trying to
identify what (evidence) exactly is involved in a crash,” Sgt.
Wade said. “We take photographs of the scene, and all of these
other gouges and skid marks will show up. This is when your
experience kicks in, looking at the items and determining what
evidence is involved in the scene and what is not.”
48 H Sheriff®
November/December 2012
Preserving scene evidence during a crash investigation is
another challenge Sgt. Wade confronts. For one scene he was
investigating, the fire department was trying to extricate a person
from a car. Recalls Sgt. Wade: “We’re doing our work, then we
hear machines and observe them (firefighters) tearing our car
apart for practice. That was our evidence!” Still another problem
can be controlling moving traffic at a crash scene. Sometimes,
cars may actually enter the crash scene itself as an investigation
is in progress. “I’ve had cars coming into the scene at 50 MPH,
and we’ve had tow truck drivers not paying attention and almost
running over our deceased body,” Sgt. Wade reveals.
‘Reflectorless’ Mode Ideal For Short Distances
Because crash scenes can occur during the day or night, total
stations are equipped to handle both situations. Most total
stations are offered in either reflector mode, requiring use of
a prism, or reflectorless mode, which allows for measurements
to objects or points without having to place a prism at those
points. Some total stations come equipped with both modes.
“The reflectorless total station is great at night,” Sgt. Wade said.
“The aiming red dot on the total station will precisely hit the
TECHNOLOGY
target it is aimed at.” The operator sets the total station’s target
height and then aims it at the desired evidence point, which,
for example, could be a tire mark. By pressing a button on the
total station’s data collector, the evidence point is captured, and
the total station has measured the slope distance. And, this has
been accomplished without a prism and someone standing over
it. “The red aiming dot helps because it’s hard to see the prism
looking through a total station,” Sgt. Wade explains. Likewise,
, he adds, “For longer scenes, you’re going to shoot reflector
mode, but, again, the red aiming dot helps because it’s hard
to see the prism looking through a total station. So, you leave
the total station in the regular mode and you activate the red
aiming light and you’ll see the red light refracted back to you
from the prism,” Sgt. Wade said.
Since most crash scenes have relatively short distances, they
can be shot with a total station in reflectorless mode. This will
speed up scene measuring dramatically compared to using
manual methods. Sgt. Wade reports that by shooting his crash
scenes reflectorless, “We’re getting a scene mapped in one
quarter of the time.”
Identifying Road Profiles Easier
Brad Booth, Senior Reconstructionist with Precision
Mapping and Reconstruction in Rapids City, South Dakota,
would agree with Sgt. Wade that correct identification and
accurate capture of scene evidence is paramount in any investigation. Which is why the total station has become such a pivotal
technology. “With the introduction of total stations, we’re able
to precisely map the evidence we identify as well as the road
designs or profiles and topography of the roads,” Booth, a former
traffic investigator with the South Dakota Police Department,
said. For example, Booth points out that in South Dakota there
is typically a three percent crown in the center of the road, and
that by working with 3D crash mapping and diagramming “we
can actually see that (crown) now when we go out and map.”
This also means more scene evidence points must be captured,
which a total station can easily and quickly accomplish. “Once
we do that, we can accurately place vehicles over the evidence,
and we can also do animation,” Booth said.
Using current mapping technology is particularly important
for Booth as he notes that crashes investigated in Rapids City
overall are trending upward. In 2011, for example, there were 2,
539 reportable accidents. Most crash scenes that Booth investigates are in rural areas, so they measure 1000 feet or longer.
With such huge scenes, collecting evidence points quickly is a
priority. “When we used tape measures, we collected at most
40 or 50 measurements, and that would take all day,” Booth
recalls. “With a total station, you can shoot to a prism in about
three seconds. And I’m taking 400 to 500 measurements regularly per scene. I’ve taken as many as 1000 measurements at a
crash scene,” Booth added.
Fatal Crash Underscores Total Station’s Value
While tape measures still are used today as the only tool or
in conjunction with other equipment, their accuracy cannot
match that of a total station. Booth knows because one crash
scene he handled showed how critical measurement accuracy
is. The incident involved a van with Girl Scouts whose driver
was turning a corner on a road too fast. The driver was forced
to overcorrect the van, causing it to veer into the opposing lane
and slam head-on into another vehicle, instantly killing two of
the Girl Scouts. Booth, a state trooper at the time, had used a
tape measure to map the scene which was just over 700 feet, and
so had to move the tape measure twice to complete measurements. He then produced a hand-drawn diagram. Meanwhile,
the South Dakota Department of Transportation also mapped
the scene, although using a total station, and had delivered its
completed diagram to Booth by the time he got to his office
the next morning. Upon viewing the diagram, said Booth, “I
was off with my measurements by over a foot. I decided at that
moment it was time we jumped onto total station technology.”
‘Seamless Integration’ of Scene Details Aided By Suite
of Tools
By now, it’s clear to see that crash scene mapping is a combination of investigative training, skills, and experience along with
reliable, precision oriented equipment. Typically, the equipment
includes a total station, data collector (in many total station
models a data collector is built in), data collection software, and
a diagramming software program. These tools allow a seamless
integration of evidence capture, plotting of evidence points, and
creation of a final scaled diagram that may be used for courtroom presentation. Booth uses a Leica total station, although he
is transitioning to a Sokkia 50R reflectorless total station, as well
as a handheld Pocket PC, TDS Recon data collector, MapScenes
Evidence Recorder software, and ARAS 360 crash diagramming
software. Contributing strongly to the seamless integration of
scene documentation, Booth says, is the MapScenes Evidence
Recorder. This is due to the software’s ability to allow its user to
visually verify ongoing field evidence collection—on the spot—
high-definition graphics, intuitive coordinates setup, and automatic saving of each measurement to ensure data security. Data
security is crucial when documenting crash scenes. Says Booth:
“The Evidence Recorder is very intuitive and does such a good
job of maintaining integrity of data we shoot. You can change
one shot and change codes.” However, Booth notes, “When we
change codes the software flags this.”
Robotic Total Stations Boost Efficiency, Accuracy,
Reduce Errors
Dave Forystek, formerly a sergeant with The Flint, Michigan,
Police Department’s Traffic Division, actually spent much of his
time investigating and mapping crime scenes. To do so, he used
a Sokkia SRX5 fully robotic, single-operator total station with
Archer Field PC, Mapscenes Evidence Recorder data collection
software, and MapScenes Forensic CAD software. Sokkia is one
of only a handful of total station makers who offer robotic total
stations. The robotic station adds automatic tracking and radio
communication to a radio and data collector at the “target” or
pole. Consequently, no person is required at the instrument—
Sheriff ® November/December 2012
H 49
TECHNOLOGY
only at the target—reducing the need for a second operator.
Robotic total stations also are servo-motor-driven, which
means they are paired with some type of encoder to provide
position/speed feedback. They measure both in the X-Y (horizontal) plane and the Z (elevation) axis. With these capabilities,
robotic total stations search for, then lock onto the target and
then automatically follow it as the investigator moves it around
a crime scene. While the total station tracks the target, it is
constantly updating the data collector.
According to Sgt. Forystek, “It’s the combination of speed
and accuracy and the amount of evidence you can gather”
that makes the robotic total station so valuable. For example,
he explains, if an investigator enters a 3000-4000 square-foot
nightclub to map it using a tape measure, he will need to walk
around it many times, and probably need to traverse around
some evidence. “Using a robotic total station in an interior
scene like this, I can stand in one location and shoot just about
everything I need,” Sgt. Forystek adds.
More Measurements in Less Time a Chief Benefit
Although there are today many options for crash scene
measuring, the total station undoubtedly will remain the most
ubiquitous and often used documentation tool. And for good
reason given its many benefits:
• The ability to take a large number of measurements in a
short amount of time.
• Reduced time spent at the scene means partially or fully
closed roads can be re-opened more quickly, which
raises safety for both investigators on scene and waiting
motorists.
• By combining the total station with software needed to
process collected data points, a simple diagram can be
created at the scene within minutes and checked for any
missed points before leaving.
A scaled diagram created with data first accurately shot with
a total station and that has been secured via collection software
allows for careful analysis of scene events and details. J
 One Piece Unit
Streamlines inventory management and reduces “out of range” alerts
 AFLT Compatible
Advanced technology enables reliable indoor and urban canyon tracking
 Omni-Directional Antenna
Delivers excellent signal reception for dependable GPS tracking
 Radio Frequency
Offers flexible monitoring options that extend battery life and lower costs
 Event Pairing
Enables officers to focus on critical alerts and higher risk cases
 Field-Replaceable Battery
Long-lasting battery saves time, money and keeps equipment in the field
 Industry-leading Monitoring Center
Provides peace of mind with the backing of continuous expert support
50 H Sheriff®
November/December 2012