Alcohol Interlock Curriculum: Technology Summary

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Alcohol Interlock CurriculumTechnologySummary
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Technology

• This section contains the following information
• How the alcohol interlock device works
• Installation
• Sensor technologies
• Accuracy
• Technical standards and certification
• How mouth alcohol affects the interlock
• Environmental influences
• Features and programming capabilities
• Tampering and circumvention
• Running retest
• Emergency override options
• Future technological advances
• Conclusions

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Introduction

• An alcohol interlock is a breath-testing device
  attached to a cars starter.
• It prevents the car from being started when a
  pre-set level of alcohol is detected in the
  breath sample presumably provided by the driver
  of the vehicle.

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Technology
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How does it work?

• The breath testing device is attached to the
  vehicle starter, or other on-board computer
  system.
• The device interrupts the flow of power to the
  starter using an open relay switch.
• If the level of alcohol detected in the breath
  sample is below a pre-set limit (usually .02),
  the relay switch is closed allowing power to flow
  to start the vehicle.
• Repeated breath tests are required while the
  vehicle is in use to ensure the driver remains
  sober after starting the vehicle.
• The alcohol interlock is not connected to the
  engine and therefore, cannot affect a running
  engine.

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How does it work?
BAC 0
Ignition
Warn
BAC lt 0.02
Running Retest
BAC gt 0.02
Interlock
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Installation

• On average, the installation of the interlock
  device takes approximately 45 minutes.
• It can take up to 2 hours depending on the
  experience of the installer and sophistication of
  the vehicle electronics.
• During the installation the offender receives
  information about the device and learns how to
  blow into it to provide a breath sample.

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Sensor technology

• There are three different types of sensors that
  may be used in alcohol interlock devices
• Semiconductor sensors
• Electrochemical sensors (fuel cells)
• Infrared sensors

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Accuracy

• Alcohol interlocks containing an electrochemical
  sensor are accurate in detecting alcohol
  consumption 99 of the time.
• Alcohol that is detected can be in the form of
  beverage alcohol that is consumed, or alcohol in
  medications or other ingested products (e.g.,
  cough syrup, mouth wash).
• The NHTSA specifications state that the alcohol
  interlock device must prevent the driver from
  starting the vehicle (even in extreme heat or
  cold conditions) 98 of the time when the BrAC is
  .065 or greater (Beirness 2001).
• The specifications emphasize prevention of
  circumvention and tampering rather than the
  precise measurement of alcohol.

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Technical standards

• Technical standards to specify the performance
  requirements of interlock devices have been
  implemented in several countries (e.g., United
  States, Canada, European Union, and Australia).
• Most jurisdictions have only one standard for
  offender-based applications.
• A few jurisdictions have additional standards for
  other classes of drivers (e.g., commercial
  drivers).

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Certification of devices

• Many jurisdictions in the U.S. require that a
  device is certified by the state to ensure that
  it meets necessary technical requirements and is
  approved for use.
• Once the device/manufacturer has been certified
  by the state, the device is approved and can be
  made available for use.
• Certification tends to be inconsistent across
  jurisdictions as the agencies doing the device
  testing and certification vary.

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Mouth alcohol

• Mouth alcohol is residual alcohol that is present
  in the mouth or throat immediately following the
  consumption of food, drink, mouth spray or
  medicine that contains alcohol.
• Mouth alcohol can register on an interlock device
  as an alcohol-positive breath sample and can
  prevent the engine of the vehicle from starting.
• This is easily overcome by waiting a few minutes
  to allow residual alcohol to dissipate, similar
  to an evidential breath test.
• Drivers are advised not to consume anything
  containing alcohol for 5 minutes prior to the
  breath test.

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Environmental influences

• Generally, extreme temperatures and altitude have
  nominal effects on alcohol interlocks.
• Devices are designed to withstand adverse effects
  of temperature and elevation similar to other
  common vehicle design technologies.
• Most interlocks can withstand temperatures
  ranging from -49 to 185 degrees Fahrenheit (-45
  to 85 degrees Celsius) and altitudes of up to
  11,482 feet (3,500 metres) (Burger 2001 cited in
  Bax et al. 2001).

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Environmental influences

• The electrochemical sensor in an interlock device
  operates at a high temperature.
• For this reason, a brief warm-up period before
  the device can analyze a breath sample is
  essential (much like a photocopier).
• Warm-up time typically spans a few minutes and is
  influenced by environmental and climatic
  variables. In extreme cold environments, a longer
  period of 5 minutes may be required.
• Technological advances have significantly reduced
  the warm-up period. These include
• detachable handset
• wireless device

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Device features

• Language and visual display
• BrAC threshold (pre-set limit)
• Lock-out time
• Stall protection time
• Pull over notice
• Recall notice
• Breath volume

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Programming the device

• In many states, the Department of Motor Vehicles
  (DMV) is responsible for certifying the alcohol
  interlock and ensuring that specific features
  have been programmed by the manufacturer.
• In a few states, service providers are
  responsible for programming.
• This can result in inconsistent programming of
  features in some devices.

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Tampering and circumvention

• There are several anti-circumvention features
  available for alcohol interlocks including
• Sealed wiring
• Temperature and pressure gauges
• Systems to reduce the likelihood of breath
  samples from non-drivers
• These include breath pulse code, hum-tone
  recognition, blow and suck method, and photo
  recognition.
• Data recorder

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Running retest

• The running retest feature ensures that a driver
  remains sober while driving.
• It requires random and repeated breath samples
  while the vehicle is in use.
• A breath sample above the pre-set limit will
  result in a warning for the driver to pull over
  and stop driving.
• The interlock will not shut off a running engine
  (Beirness 2001).

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Emergency override

• The emergency override is a feature available on
  some alcohol interlocks.
• It allows the driver to avoid providing a breath
  sample before starting the vehicle one-time only.
• The availability of the override feature is
  contingent on approval from the program
  administrator i.e., some jurisdictions permit
  it while others do not.
• There are ethical concerns associated with the
  non/use of this feature as it has the potential
  to create liability if abused.

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Future technological advances

• In the future, alcohol interlocks may be a
  standard feature on all vehicles.
• In order to achieve general acceptance, this
  technology must be unobtrusive, fast, accurate,
  reliable, and repeatable.
• It must also be functional across a wide range of
  driving and environmental conditions, require
  little or no maintenance, and be tamper and
  circumvention resistant.

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Future technological advances

• The following technologies are currently being
  developed
• Infrared spectroscopy
• Vapour detection
• Transdermal alcohol monitoring
• Vehicle-based impairment detection
• Ocular measures

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Conclusions

• An alcohol interlock requires a driver to perform
  a breath test to start a vehicle, and provide
  repeated breath samples while the vehicle is in
  use.
• Advances in alcohol interlock technology have
  overcome many of the limitations associated with
  earlier devices.
• Technical standards and certification
  requirements govern the use of delivery of these
  devices across jurisdictions.
• Devices can withstand many environmental
  influences and have a variety of programmable
  features.

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Conclusions

• Devices possess a variety of features to prevent
  tampering and circumvention.
• A data recording device records all relevant
  vehicle activity.
• Use of the emergency override feature varies
  across jurisdictions.
• Other alcohol detection technologies are being
  explored to gauge their potential for use in all
  vehicles.

13.05.09