Diabetes and Commercial Driving (and other Safety Critical Work)

Diabetes and Commercial Driving 

(and other Safety Critical Work) 

Dr Bruce Hocking 

Specialist in Occupational Medicine 

A/Professor Stephen Twigg 

Endocrinologist, Royal Prince Alfred 

Hospital, and The University of Sydney



Aims 

• To introduce concepts of medical 

standards for Safety Critical Work. 

• To familiarise usage of Assessing Fitness 

To Drive when examining commercial 

drivers with diabetes.

Kempsey 1989 – 35 dead 

- no skid marks - sleep?

Coroners cases - Bednarek SA (2001) 

• Shantel Bednarek died in 1999 after being struck by a 

car driven by a person with diabetes, Mr Greg 

Johnson, during a hypoglycaemic episode (blood 

glucose level, 3.0 mmol/L). 

• He had poorly controlled insulin dependent (type 1) 

diabetes and “hypoglycaemic unawareness”. Mr 

Johnson worked as a car salesman (!) and had one 

episode of hypoglycaemia at work, for which he 

required admission to hospital. 

• Johnson was seen by various doctors who gave 

varying advice regarding driving so Johnson was able 

to claim that he had never been properly told that he 

could not drive. 

• There is a need for doctors to be clear when advising 

patients not to drive and to document this clearly in 

their records.

Coroners cases. Sheriff Vic.(2005) 

• Mr Sheriff was a road worker who was killed by 

a truck driven by a man with diabetes, Mr Glenn 

Robertson, during an episode of hypoglycaemia 

(December 2002). 

• The Coroner recommended that the guidelines 

for medical examiners in relation to Commercial 

Vehicle Drivers be reviewed and the criteria for 

driving in respect of type 1 diabetes ought to be 

more stringent such that applicants who require 

insulin therapy shall not be entitled to hold 

commercial or passenger carrying vehicle 

licences unless certain criteria are satisfied

Bus driving

DG (petrol) tanker driving

Road Train Driving

Emergency Services 

- not all police drive pursuit!

Fork lift driving can be hazardous 

to the driver and others

Train Driver (solo)

Waterfall train disaster – 7dead- VF 

Legal rulings re medical examination

Maritime Pilots 

- huge forces in a confined space

Setting medical standards for 

Safety Critical Work 

The Medico-legal environment 

• Duties of care 

• EEO 

• Privacy

Medico-legal context of standards. 

Medical standards sit in 3D legal space. 

Disability 

Discrimination 

Medical 

standards 

Privacy 

Duties of care. 

(OHS, public 

liability, envt)

Development of health assessment standards begins 

with defining the inherent requirements then 

identifying the necessary health attributes and finally 

setting the medical criteria. Diabetes has multiple 

potential effects (vision. cardiac, hypoglycaemia). 

Inherent 

requirements 

Define nature 

of task 

Health attributes 

Define health 

attributes linked to 

inherent 

requirements 

-Senses, 

-M/Sk, 

-Cognitive, 

-General Health 

(acute incapacity) 

Health 

assessment 

& medical criteria 

Define the tests 

required to 

measure 

health status in 

relation to the 

health 

attributes and 

criteria to judge 

fitness for duty

Diabetes – Medical Criteria 

5.1 RELEVANCE TO DRIVING TASK 

Diabetes may affect a person’s ability to drive due to: 

• Loss of concentration or consciousness in a 

hypoglycaemic episode, or 

end organ effects relevant to driving: 

• Vision (fields, acuity) 

• Ischaemic heart disease 

• Peripheral nerves and vasculature of the extremities, 

particularly the feet.

Risk Stratification of Diabetes and 

Driving 

Private 

Vehicle 

Commercial 

Vehicle 

(may subdivide 

DG & Buses) 

Type 1 --------------------- 

--------------------- 

--------------------- 

Type 2 --------------------- 

--------------------- 

---------------------

Diabetes – Medical Criteria - Vision 

Acuity 

• Private vehicle 

The criteria for an unconditional licence are NOT met: 

– If the person's visual acuity in the better eye or with both 

eyes together is worse than 6/12. 

• Commercial Vehicle. 

The criteria for an unconditional licence are NOT met: 

– If the person's visual acuity is worse than 6/9 in the better 

eye; or 

– If the person's visual acuity is worse than 6/18 in either eye. 

• A conditional licence may be granted by the Driver 

Licensing Authority……………………,


Visual Fields (eg laser surgery) 

• Commercial vehicle 

The criteria for an unconditional licence 

are NOT met: 

- If the person has any visual field 

defect. 

• A conditional licence may be granted by 

the 

Driver Licensing Authority,……………….

Fundus photo showing scatter laser 

surgery for diabetic retinopathy

Diabetes – Medical Criteria - Cardiac 

Angina 

• Commercial Vehicle 

• The criteria for an unconditional licence are NOT 

met: 

- If the person is subject to angina pectoris. 

• A conditional licence may be granted by the 

Driver Licensing Authority,…………….. 

- treadmill test, angiogram, etc. 

- noting other risk factors eg diabetes.

Clinical Case #1 

• New patient: 35yrs male Type 1 diabetes 

diagnosed 3 months ago 

• Commercial truck driver from Griffith 

• Heavy rigid vehicle 

• Overnight shifts 

• Recently commenced on twice daily 

Mixtard 30/70, 20 units bid s.c. 

• One episode of severe nocturnal 

hypoglycaemia 1 month previous


• What other information (medical, 

occupational, etc) would you like to know?


• What medical concerns do you have?


• OP. What advice would you provide to him and 

the employer regarding fitness for duty? 

• Endocrinologist: He asks for a certificate for the 

Driver Licensing Authority in support of renewal 

of his licence. What do you write?


• 25 year old female, Type 1 diabetes, 15 years duration 

• Enjoys driving, completing a TAFE Course in computer 

science, but wants to commence as a full time bus 

driver 

• Bus driving in metro Sydney, involves shift work. 

• Had one episode of hypoglycaemia after a few alcoholic 

drinks at her 18 th birthday party 

• On Lantus once daily and Novorapid with each main 

meal, tds 

• No microalbuminuria 

• Vision (acuity, fields) OK, fundus shows early 

maculopathy. 

• No peripheral neuropathy 

• No history of macrovascular disease


• What further information would you like to 

know?


• OP. What advice would you provide to the 

employer regarding fitness for duty? 

Justify it. If she were accepted for 

employment what advice would you give 

her? 

• Endocrinologist: She asks for a certificate 

in support of her licence for the Driver 

Licensing Authority. What do you write?


• If she became pregnant how would you 

manage her ?


• 54 year old male, Type 2 diabetes, 11 years 

duration, commercial truck driver 

• Drives semi-trailer, interstate overnight. 

• Needs to commence insulin due to secondary 

failure: HbA 1C 10.4% 

• No albuminuria 

• Diabetic maculopathy – past laser treatment 

• No history of macrovascular disease 

• Dense peripheral neuropathy with Charcot’s 

arthropathy of left foot recently diagnosed


• BP 130-138/85-94 mmHg 

• LDL-C 2.1 mM on Simvastatin 

• Alcohol intake 20-40 g nocte


• What further information would you like to 

know?


• OP. What advice would you provide to him 

and the employer regarding fitness for 

duty? 

• Endocrinologist: He asks for a certificate 

for the Driver Licensing Authority in 

support of renewal of his licence. What do 

you write?

ADS Working Party 

• ADS is preparing a position statement on 

“Diabetes and Driving”. 

- Co-Chairs: Chairs: Professor Kamp and Professor Twigg 

- Systematic review of international guidelines, 

coroner’s s cases and published literature 

- Summary supplementary guidelines for clinical care 

• Professional education and support materials 

• Patient education and support materials

ADS WP: Patient Education 

• Develop patient education materials. 

– Diverse effects of diabetes on driving 

– Legal issues re licensing 

– Treating doctors role 

– Help (web sites, etc.) 

• Marketing via multiple channels 

– National Diabetes Services Scheme 

• Views of ADEA and DA to be sought.

Questions and Discussion



Learning Aims 

• To introduce concepts of medical 

standards for Safety Critical Work. 

• To familiarise usage of Assessing Fitness 

To Drive when examining diabetic 

commercial drivers.

Diabetes and Driving 

– some international evidence 

• No definite overall increased risk of 

accidents overall 

• Diabetes high risk sub-groups for 

accidents: 

– type 1 diabetes 

– the elderly 

– history predicts the future 

• Best methods to prevent accidents in 

people with diabetes?

Diabetes and Driving: 

Some Recent Publications 

• Lonnen KF etal., Diabet Med. 2008 May;25(5):578-84. Road traffic accidents and diabetes: 

insulin use does not determine risk. [UK] 

• Hayashino Y etal. Exp Clin Endocrinol Diabetes. 2008 Jan;116(1):1-5. Epub 2007 Oct 31. 

Relationship between diabetes mellitus and excessive sleepiness during driving. [Japan] 

• Stork AD, etal. Diabetes Care. 2007;30(11):2822-6. The decision not to drive during 

hypoglycemia in patients with type 1 and type 2 diabetes according to hypoglycemia 

awareness. [Netherlands] 

• Songer TJ, Dorsey RR. Annu Proc Assoc Adv Automot Med. 2006;50:335-351‘High risk 

characteristics for motor vehicle crashes in persons with diabetes by age’; ‘Severe 

hypoglycemia was consistently and strongly related to crashes at all ages.’ 

• Diamond TH, Collins J, Rohl P. Aust Fam Physician. 2005;34(3):151-4. Motor vehicle 

accidents during episodes of hypoglycaemia - 5 case reports and lessons to be learnt. [Aust] 

• Szlyk JPetal., Relationship of retinal structural and clinical vision parameters to driving 

performance of diabetic retinopathy patients. J Rehabil Res Dev. 2004;41(3A):347-58. 

• Graveling AJ etal., Hypoglycaemia and driving in people with insulin-treated diabetes: 

adherence to recommendations for avoidance. Diabet Med. 2004 Sep;21(9):1014-9.

Stork ADM, van Haeften TW, Veneman TF: 

Diabetes and Driving (Review). 

Diabetes Care 29:1942–1949, 2006 

• ‘Evaluation of the available research on diabetes and driving is difficult. 

• Most older studies have either found no association between diabetes 

and traffic accidents or a small, usually not statistically significant, 

increase of the relative risk. 

• More recent U.S. research, however, indicated a clear trend, frequently 

statistically significant, toward a slightly increased risk of road traffic 

accidents in diabetic drivers. The increase of the relative risk in some 

studies was only found in specific subgroups of diabetic patients, not 

consistent throughout various studies. 

• Overall, the available studies indicate that road traffic accidents directly 

caused by diabetes seem to be relatively rare occurrences. 

• Without doubt, hypoglycemia during driving does occur and can cause 

traffic accidents. 

• If any trend can be distilled, current knowledge may point toward a slightly 

increased risk of road traffic accidents for drivers with diabetes. However, 

no subgroup that is particularly at risk has been unequivocally defined.’




• ‘Taken together, although various studies find an increased 

accident rate among diabetic subjects, other studies do not 

or even show a lower rate. Some studies had relatively 

small numbers of diabetic patients. The most 

methodologically accurate studies on drivers aged >65 

years indicates that there might be specific subgroups of 

diabetic patients that are at increased risk.’ 

• ‘Studies clearly indicate that an increased risk for (a subset 

of) diabetic truck drivers could very well exist.’ 

• ‘Koepsell et al. (diabetes in the elderly) found a 2.6-fold 

increase in injury risk for diabetic drivers, which was even 

higher (OR 5.8) for patients treated with insulin, or oral 

hypoglycemic agents (3.1) and for drivers with duration of 

diabetes >5 years (3.9).’




• ‘Songer and Lave have estimated that if diabetic patients would 

be licensed to drive commercial motor vehicles, mild and 

moderate hypoglycemia would increase the amount of accidents 

6.1-fold for insulin-dependent diabetic patients and 4.1-fold for 

non–insulin-dependent diabetic patients, resulting in an additional 

42 accidents per year in the U.S. 

• The risks of diabetic drivers with a history of severe hypoglycemia 

would be increased nearly 20-fold. However, they also estimate 

that if these latter diabetic subjects are excluded, the relative risk 

drops to 3.7 and 2.7, respectively, and the number of additional 

accidents per year to 20. …The same authors conclude that 

given the fact that other higher risks are generally accepted (e.g., 

driver’s licenses from the age of 16 years, allowing some unsafe 

motorways, etc.), the additional risks from insulin-using 

individuals are well within the accepted range of risk.’




• ‘Blood glucose awareness training may well be a 

relatively easy and effective method to reduce traffic 

violations and accidents in diabetic patients.’ 

• ‘It can be concluded that only a very small proportion of 

road traffic accidents are caused by a medical condition 

in general and by diabetes in particular.’

In Summary 

• Diabetes and driving is an important issue to be 

addressed and individualised in patient care 

• Rarely, highly adverse outcomes can occur due to 

diabetes in people who drive 

• Patient rights/minimisation of discrimination vs 

patient and civil safety, requires a balanced 

approach 

• Methods likely exist to reduce the risk of adverse 

outcomes.

Coroners Rec’s re IDDM (Sheriff) 

a) the patient retains an appropriate specialist that he/she is required to attend 

four times per year (or with such other regularity as the specialist certifies 

as appropriate); 

b) the patient submits to regular Hb Alc testing as the specialist deems 

appropriate; 

c) the patient provide regular proof to the specialist of blood sugar level testing 

(ideally a downloaded log from a memory equipped blood glucose meter) 

as regularly as the specialist deems appropriate; 

d) the specialist certify to VicRoads on a yearly basis that the patient’s diabetes 

is under control; 

e) the patient adhere to an appropriate diet and regime of medication that may 

be established by the specialist;

Coroners Rec’s re IDDM (Sheriff) 

f) in the event of the patient suffering any hypoglYcaemic episode 

involving loss of consciousness or loss of control of motor ability, the 

specialist, or any other medical practitioner, or the police, should 

formally report the matter to VicRoads and the person’s commercial 

licence should be suspended; 

g) in the event of a hypoglycaemic episode as above, the licence 

should not be reinstated unless the specialist certifies that: 

i) a period of 12 months has elapsed during which there has 

been no further hypoglycaemic episodes; 

(ii) the specialist is satisfied as to the cause of the previous 

hypoglycaemic event; 

(iii) the specialist is satisfied no further hypoglycaemic event will 

occur without there being some forewarning to the patient.

Risk Analysis of Medical Factors in 

MVA (Spencer etal Clin Med 2004) 

Risk of casualty from MVA = 

• Pr illness event (episodic hypo’) x 

• Pr event occurring when driving (exposure) x 

• Pr event when driving will lead to crash x 

• Pr crash will lead to casualty. 

Problem of increasingly wide confidence 

intervals with each calculation. 

What level of risk is acceptable? and to whom?


Visual Fields (eg laser surgery) 

• Private vehicle 

The criteria for an unconditional licence are 

NOT met: 

- If the binocular visual field does not have a 

horizontal extent of at least 120 degrees 

within 10 degrees above and below the 

horizontal midline; or 

- If the person has a hemianopia; or etc

ADS WP Professional Education 

• Appreciating overall risks in people with diabetes 

who drive 

• Assessing which patient groups and individuals 

with diabetes are at especially high risk of motor 

vehicle accidents 

• Clinical care supplementary guidelines 

• Supplementary written support materials for: 

– assessing commercial drivers with diabetes 

– managing severe hypoglycaemia

Diabetes – Medical Criteria - Cardiac 

Angina 

• Private Vehicle. A person with angina which is usually 

absent on mild exertion and who is compliant with 

treatment may drive without licence restriction and 

without notification to the Driver Licensing 

Authority, subject to periodic review. 

• The criteria for an unconditional licence are NOT met: 

- If the person is subject to angina pectoris at rest or on 

minimal exertion despite medical therapy, or has 

unstable angina. 

• A conditional licence may be granted by the 

Driver Licensing Authority, …………….

Diabetes and Commercial Driving (and other Safety Critical Work)

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