Mandatory Retesting of Drivers Dr Richard Tay AMA/CTEP Chair in - - PowerPoint PPT Presentation

Mandatory Retesting of Drivers Dr Richard Tay

AMA/CTEP Chair in Road Safety Department of Civil Engineering

Adjunct Professor in Injury Prevention Adjunct Professor in Injury Prevention Department of Community Health Sciences

University of Calgary U ve s ty o Ca ga y

Adjunct Professor in Road Safety School of Psychology and Counseling y gy g Queensland University of Technology

November 2007

Introduction

• The demographic profile of drivers in many countries are changing as

the baby boomer generation matures.

• Older drivers on the roads have generated much concern among some

g g road safety researchers and policy makers.

• Major concerns: Anticipated decrease in driving ability.
• Extensive research have been conducted on the relative performance of
• lder drivers and on their crash risks relative other age groups.
• Antsey et al (2005) provides a good summary of the major findings in

Antsey et al (2005) provides a good summary of the major findings in the research literature.

S l ti tt ti i f d t b l t d ith h b t th

Ageing Driver Performance

• Selective attention is found to be correlated with crashes but the

correlation is only is only 0.03, which implied that these abilities were able to explain less than 0.1% of the variations in crash risks.

• Divided attention is also found to be correlated with crashes but the

correlation is only is only 0.14, which implied that these abilities were able to explain less than 2% of the variations in crash risks.

• Visual attention is found to be correlated with crashes. The highest

correlation (0.32) is for the useful field of view. UFOV is able to explain about 10.2% of the variations in crash risks.

• Movement Perception Test: correlation is only is only 0.26, which

implied that these ability were able to explain less than 7% of the variations in crash risks variations in crash risks.

Ageing Driver Performance

• Mental flexibility – Incompatibility Test: correlation is only is only 0 14
• Mental flexibility – Incompatibility Test: correlation is only is only 0.14,

which implied that these abilities were able to explain less than 2% of the variations in crash risks. Vi l ti l T t P F ldi T t l ti i l i l

• Visual-spatial Test – Paper Folding Test: correlation is only is only

0.33, which implied that these abilities were able to explain less than 11% of the variations in crash risks.

• Reaction Time: correlation is only is only 0.25, which implied that these

abilities were able to explain about 6.25% of the variations in crash risks.

• Visual Memory – Wechsler Test: correlation is only is much higher at

Visual Memory Wechsler Test: correlation is only is much higher at 0.5, which implied that these abilities were able to explain about 25% of the variations in crash risks.

• Traffic Sign Recognition Test: correlation is only is much higher at 0 65
• Traffic Sign Recognition Test: correlation is only is much higher at 0.65,

which implied that these abilities were able to explain about 42% of the variations in crash risks.

Ageing Driver Performance

• Mental Status

MMSE: Results very mixed from not important at all to

• Mental Status – MMSE: Results very mixed from not important at all to

correlation of 0.72, which implied that these abilities were able to explain 0%-52% of the variations in crash risks.

M t l St t MMSE R lt i d f t i t t t ll t

• Mental Status – MMSE: Results very mixed from not important at all to

correlation of 0.34, which implied that these abilities were able to explain 0%- 11.5% of the variations in crash risks.

• Overall, the results are not encouraging for the various driver

performance tests.

• They do fairly well in predicting test scores on driving simulator or

They do fairly well in predicting test scores on driving simulator or even on-road test driving test but only low-moderate in predicting crashes.

• Driver Performance ≠ Driver Behavior ≠ Safety

Ageing Drivers Licensing in Alberta

300 350 400 150 200 250 300 al Crashes 50 100 150 Fata 100000 120000 140000 160000 180000 200000 220000 240000 Number of Drivers (>65)

• Increasing number of licenses issued to ageing does not result in more

fatal crashes on the roads

Ageing Drivers Licensing in Alberta

300 350 400 150 200 250 300 al Crashes 50 100 150 Fata 80000 100000 120000 140000 160000 180000 Number of Drivers (>75)

• Increasing number of licenses issued to ageing does not result in more

fatal crashes on the roads

Ageing Drivers Licensing in Alberta

20000 25000 10000 15000 ury Crashes 5000 Inju 100000 120000 140000 160000 180000 200000 220000 240000 Number of Drivers (>65)

• Increasing number of licenses issued to ageing is correlated with more

injury crashes on the roads

Ageing Drivers Licensing in Alberta

20000 25000 Crashes 10000 15000 r of Injury C 5000 Number 80000 100000 120000 140000 160000 180000 Number of Drivers (>75)

• Increasing number of licenses issued to ageing is correlated with more

injury crashes on the roads

Ageing Drivers Licensing in Alberta

H th iti l ti hi i l t f b th d i

• However, the positive relationship is also true for both younger drivers

(25 yrs and below) and middle-aged drivers (25-65 yrs old).

• Multivariate statistical analysis is needed to estimate the marginal effects
• f changing driver mix on injury crashes.
• Poisson regression model is estimated.

Variable Coefficient P[|Z|>z] Mean of X Constant 6.407530386 .0000 TREND -.2035608051 .0000 8.0000000 GAS .2156007E-06 .0000 3840244.3 Young .7978394E-05 .0000 356724.13 MidA 3995102E 05 0000 1545380 1 MidAge -.3995102E-05 .0000 1545380.1 Ageing .4338395E-04 .0000 170185.93

Ageing Driver Re-Licensing in Canada

• No uniform license renewal and re testing policies across Canada
• No uniform license renewal and re-testing policies across Canada.
• Ontario:
• Every 2 years from 80 onwards
• Vision test
• Written test
• Discussion
• On road test if recommended after discussion
• On-road test if recommended after discussion
• Alberta:
• 75 onwards
• Medical report
• Vision test
• British Columbia:
• Every 2 years from 80 onwards – medical exam
• Testing only when reported (police or medical)

Ageing Driver Re-Licensing in Canada

3

Fatal Crashes (all ages) per Licensed Ageing Drivers

2 2.5 3 AB 0.5 1 1.5 BC ON 1998 1999 2000 2001 2002 2003 2004

• No clear relationship between testing requirements for ageing drivers

and overall safety.

Concluding Remarks

Th l l i i th t i NOT i t t f t i d idi

• The general conclusion is that age is NOT an important factor in deciding

whether one should get a license or not.

• Physical & cognitive abilities vary considerably among drivers of the
• Although our physical abilities decrease as we aged, we gain experience

and many of compensate by driving more carefully, driving in less risky same age group. and many of compensate by driving more carefully, driving in less risky environment and simply driving less.

• There is no correlation between the number of fatal crashes on the

roads and the number of licenses issued to drivers aged 65 and above roads and the number of licenses issued to drivers aged 65 and above.

• There is a positive correlation between the number of injury crashes
• n the roads and the number of licenses issued to drivers aged 65 an

above.

• This correlation may reflect the increased fragility of ageing drivers.

Alth h l t l d iti t t h b f d t b

Concluding Remarks

• Although several perceptual and cognitive tests have been found to be

correlated with crash risks, most of the correlations are quite small.

• More importantly, most of the studies did not report any measure of

p y p y predictive validity or accuracy of the tests.

• Without knowing the sensitivity and specificity, we do not know if these

tests can accurately predict whether a driver will be involved in the crash y p in the near future.

• It is therefore not surprising that jurisdictions with stricter license renewal

requirements for ageing drivers did not necessarily experience lower q g g y p crash rates.

• More research into identifying tests with higher predictive validity is

needed before any mandatory re-testing can be recommended. y y g

Thank You! Thank You! Questions Questions? Questions Questions

References

• Anstey K, Wood J, Lord S & Walker J (2005) Cognitive, sensory and physical factors

Anstey K, Wood J, Lord S & Walker J (2005) Cognitive, sensory and physical factors enabling driving safety in older adults, Clinical Psychological Review, 25, 45-65

• Grabowski D, Campbell C & Morrisey M (2006) Elderly licensure laws and motor vehicle

fatalities, Journal of the American Medical Association, 291(23), 2840-2846

• Langford J, Fitzharris M, Newstead S & Koppel S (2004) Some consequences of different
• lder driver licensing procedures in Australia, Accident Analysis and Prevention, 36, 993-

1001 Li G B E & Ch L (2003) F ilit i h i l t

• Li G, Braver E & Chen L (2003) Fragility versus excessive crash involvement as

determinants of high death rates per vehicle-mile of travel among older drivers, Accident Analysis and Prevention, 35, 227-235

• Morrisey M & Grabrowski D (2005) State motor vehicle laws and older drivers, Health

Morrisey M & Grabrowski D (2005) State motor vehicle laws and older drivers, Health Economics, 14, 407-419

• Tay R (2006) Ageing Drivers: Storm in a teacup? Accident Analysis and Prevention, 38,

112-121

• Tay R (in progress) Effectiveness of Mandatory Re-testing of Drivers, report to the Alberta

Motor Association Traffic Safety Foundation.