RITA: Measuring impairment due to alcohol and other drugs at the roadside

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RITA Measuring impairment due to alcohol and
other drugs at the roadside

• Brian Tiplady
• 26th October 2006

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RITA Measuring impairment due to alcohol and
other drugs at the roadside

• Brian Tiplady
• 26th October 2006

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Alcohol and Driving

• Large, effects on accident risk
• Moderate amounts of alcohol lead to substantial
  increase in risk

Source Compton et al., 2002
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Alcohol Impairments

• Lab tests show impairment on a wide variety of
  abilities
• Attention
• Motor skills
• Memory
• Comprehension and Judgement
• Both speed and accuracy of performance are
  important

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Other Drugs and Driving

• Performance effects easy to demonstrate in
  laboratory at relevant doses
• Much harder to demonstrate increased driving risk
• New methods such as responsibility analysis have
  increased reliability
• Now accepted that both prescription and illicit
  drugs impair driving
• Benzodiazepines (when taken during the day, e.g.
  for anxiety)
• Cannabis

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The Enforcement Problem

• An offence to be in charge of a motorised vehicle
  while unfit to drive through drink or drugs
• Alcohol is easy to measure in the body, and de
  facto limits can be set up based on lab evidence
• Other drugs present different problems
• Non-invasive assays generally not adequate
• Many drugs and more metabolites
• Illicit drugs are much harder to study
• Drugs other than alcohol, particularly illicit
  ones, are a growing problem

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The Enforcement Problem

• In practice, for drugs other than alcohol
• Only presence or absence of drug can be
  determined with sufficient reliability
• Impairment must be demonstrated in the individual
  case, and cannot be inferred from drug
  concentrations
• Present method is Field Impairment Testing

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Field Impairment Testing (FIT)

• Administered by trained Police Officers
• Pupil examination
• Estimate 30 seconds
• Walk heel to toe along a straight line and turn
• One leg stand
• Finger to nose with eyes shut
• Effective, but has considerable subjective
  element
• Could we do better with objective tests similar
  to those used in the lab?

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Home Office Scientific Branch (HOSDB) Project

• Development of a portable roadside screening
  device for driver impairment
• Battery of tests assessing different aspects of
  driving ability
• Tests should be straightforward, consistent, and
  easy to use by all drivers
• Short duration (10 minutes)
• Sensitive to effects of a wide range of legal and
  illicit drugs

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Home Office Scientific Branch (HOSDB) Project

• Phase I Development and evaluation of several
  prototype systems
• Phase II Development of single portable tester
  at HOSDB, with range of candidate tests
• Phase III Evaluation of tester
• Substantial numbers of subjects
• Wide age-range
• Variety of drugs (alcohol, prescribed, illicit)

Main target is drugs other than alcohol. Alcohol
is useful for evaluation because of its
well-documented effects
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Phase I Layout of one tester
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Phase I Layout of one tester
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Tests in one Phase I System

• Arrow Flankers
• Attention in the presence of distracting
  information
• Paired Associate Learning
• Spatial working memory
• Length Estimation
• Size judgements

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Arrow Flanker Test
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Arrow Flanker Test
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Arrow Flanker Test
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Evaluations of Prototype Tester

• Volunteer Study with Alcohol
• 15 healthy volunteers (8 male, aged 18-35) took
  part
• Low (50 mg/100 ml) and high (80) alcohol showed
  significant impairment compared to placebo
• Impairment to both speed and accuracy

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Evaluations of Prototype Tester

• Field Study at Music Festivals
• 55 volunteers recruited (30 male, aged 17-45)
  took part
• Drug and alcohol consumption from questionnaire
• Cozart saliva test and breathalyser
• Performance on impairment tester

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Overall Impairment Index
ANOVA Ethanol F 7.36 plt0.01 Drug F
0.55 n.s. Interaction F 0.17 n.s.
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Overall Impairment Index
Pairwise Comparisons High vs Zero t
3.58 plt0.001 Low vs Zero t 0.13 n.s.
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Arrows Speed Accuracy
Red Circles High Alcohol Open Circles No and
Low Alcohol
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Conclusions

• Prototype devices effective both in lab and field
  settings
• Impairments to speed and accuracy of performance
  were detected
• Overlap between impaired and non-impaired persons
  may be an issue
• Concept warrants further development

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Phase II Roadside Impairment Testing Apparatus
(RITA)

• Selection of tests from prototypes (30 mins)
• Critical Tracking Task
• Length Estimation
• Paired Associate Learning
• Sustained Attention to Response Test
• Choice Reaction Time
• Arrow Flanker Task
• Implementation on Handheld Device at HOSDB
• 14 cm diagonal screen size
• Input via touch screen and push buttons

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Phase III

• Large scale evaluations
• N of subjects in the 00s
• Wide range of ages
• Alcohol evaluation study
• Recruitment complete
• Study/studies on other drug classes
• Test selection for final ten minute battery

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Phase III Alcohol Evaluation

• Carried out at Royal Infirmary, Edinburgh
• 120 volunteers spread evenly across age-bands
  18-24, 25-30, 31-40, 41-50, 51-60, 61-70
• Three sessions one dose-finding and two main
• Dose of alcohol to take them to a maximum blood
  alcohol concentration of 90 mg/100ml
• Sufficiently well-tolerated
• Most people unfit to drive at this concentration
• RITA and FIT carried out over next 2 hours
• Taxi home at end of session

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Phase III Key Dates 2005/6

• 22nd November Phase III presented to
  Governments Science and Technology Committee
• 1st December Protocol submitted to ethics
  committee
• 4th December Article in New Scientist
• 25th January Recruitment started
• 4th April Article on study in local paper
• 7th September Sessions completed
• Ongoing Data review and analysis

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Recruitment

• Initially by newspaper advertisement
• Posters in waiting rooms, places of work
• Flyers distributed carryouts were particularly
  effective
• Word of mouth became increasingly important as
  study went on

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Recruitment
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Summary and Conclusions

• Once sensitivity to alcohol is established, work
  with other drugs may be initiated
• Opportunity both to improve enforcement and to
  obtain more detailed knowledge of drug effects on
  driving skills
• Persuasion is as important as enforcement

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Brian Tiplady Contact Information
T 0131 447 2171 M 07760 263 283 E
brian_at_penscreen.com W www.penscreen.com
Thanks to
University of Surrey Andria Degia Julia
Boyle HOSDB Philip Dixon University of
Edinburgh Gordon Drummond Stephanie
Dodds Caroline Maciver Clinical Research
Facility, Jean AntonelliEdinburgh Sharon
Cameron Finny Paterson
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Brian Tiplady Contact Information