Diabetes and the Open Road—Are You Driving While Low?

This article was originally published in Diabetes Health in October, 1999.

The consensus among readers who commented was that people with diabetes are legally responsible for making sure that the disease does not affect their ability to drive safely when they get behind the wheel. What do you think about this topic? Send us your comments (at the bottom).

| Nov 10, 2008

A study published in the August 25 Journal of the American Medical Association (JAMA) reports that people with type 1 diabetes "may not judge correctly when their blood sugar levels are too low and may consider driving with a low BG." In the study, "low" was defined as less than 70 mg/dl.

Two separate groups of patients were recruited two years apart from four academic medical centers, totaling 158 type 1 subjects. The subjects would enter data into hand-held computers to record how they felt, what they estimated their blood sugars to be, and whether they would make the decision to drive. Then, they would measure their blood sugar. They did this several times a day for a few weeks, and were never instructed about safe driving ranges before or during the study.

When actual blood sugars were 60 to 70 mg/dl, subjects said they would drive nearly 45 percent of the time.

"Our data suggest that persons with type 1 diabetes may not judge correctly when their blood glucose is too low to permit safe driving..." writes William Clarke, MD, of the University of Virginia Health Sciences Center. Clarke adds that people with diabetes should be aware of the danger of relying on their ability to detect low blood sugar without testing it.

I Have to Get to Work

Miriam E. Tucker, a medical journalist in Rockville, Maryland, who has type 1 diabetes, feels frustrated by studies like the one in JAMA.

"I have to get to work or wherever I'm going," says Tucker. "I have sugar in my car and I've driven plenty of times with low blood sugars. If it's low enough I'll eat sugar. You can eat and drive. The two are not mutually exclusive."

Tucker says that the authors of the JAMA study make it sound like people with diabetes irresponsibly get into a car and do not think about how they are feeling.

"The message that gets out with these kinds of studies is, 'Oh my God, all these diabetics are out driving around.' It is possible to treat your low blood sugar while you are living your life and moving around."

Tucker emphasizes that she eats sugar whenever she is feeling low and always keeps glucose tablets and hard candy in her car in an easy-to-reach place.

Speaking with DIABETES HEALTH, Clarke says that people with diabetes should instead pull over to the side of the road, turn off the engine, engage the brake and treat the low BG.

"Then, they should wait 10 to 15 minutes until their brain recovers from the low BG," he says. "The recovery of cognitive function lags behind the recovery of a low BG."

Poor Judgment To Drive With a Low Blood Sugar

John Hunt, MB, BS, FRCP, a clinical associate professor at the University of British Columbia's division of endocrinology, says that some people with diabetes lose judgment as the first symptom of low blood sugar and therefore do not recognize that they are low, do not eat, and may finish up with severe hypoglycemia.

"I despair for these people," says Hunt, who tells his patients who drive to always carry sugar in the car where they can reach it easily, like the glove compartment or on the seat beside them. "I don't know how many people actually follow this advice, and I hate to ask. The point is that [people with diabetes who drive] have a responsibility to themselves, other drivers and their families to take all reasonable precautions to prevent hypoglycemia while driving in the first place."

Kriss Halpern, a southern California attorney with type 1 diabetes, says that no person with diabetes should drive if his or her BGs are below 50 mg/dl (see "Diabetes and Driving Responsibilities"). Although the JAMA study did not designate an unsafe BG driving level, Clarke suggests that people treat BGs that are 80 mg/dl or lower to prevent them from falling lower during driving.

Clarke points to a similar study of his that was published in a February 1993 issue of Diabetes ("Driving Decrements in Type 1 Diabetes During Moderate Hypoglycemia"). In that study, Clarke and colleagues at the University of Virginia found that BG levels between 47 and 65 mg/dl were associated with driving problems in 35 percent of the patients. Clarke wrote that people with diabetes "should be instructed not to drive without treating blood glucose below [65 mg/dl]."

Clarke adds that an additional study on low blood sugars and driving will be published in Diabetes Care later this fall. This study, like the ones in Diabetes and JAMA, will "further demonstrate changes in symptoms and in physiologic responses with BGs under 70 mg/dl."

Don't Blame The Victim

Joan Hoover, DIABETES HEALTH's patient advocate advisor from Chevy Chase, Maryland, is disappointed with the JAMA study.

"Diabetes does not make you stupid," she argues. "Diabetic drivers are not eager to endanger their own lives and the lives of others."

Hoover calls into question the conclusions reached by Clarke and colleagues at the University of Virginia.

"I'm disturbed by the implication that diabetic driving problems are a result of conscious, bad decisions on the part of the diabetic driver," says Hoover. "Hypoglycemia can have many origins, most of which are poorly understood. Neuropathy can alter the signals of an impending insulin reaction. Also, followers of the DCCT often tend to keep their glucose levels dangerously low."

Hoover adds that any effort to "blame the victim" for hypoglycemia-related motor accidents serves only to "misinform and to push the eventual solution just that much further out of reach."

Diane Bayliss of Brockville, Ontario, feels that there are many medical conditions that can develop while driving, and that low blood sugar is just one of them.

"Just as people with diabetes can have hypoglycemia, a nondiabetic person can experience a heart attack," says Bayliss. "I would think that a person with diabetes would be at less risk of creating an accident because he or she is so aware of the health and potential risk factors."

Doctors Should Counsel Their Patients

The JAMA article points out that no study has ever demonstrated a higher incidence of automobile crashes among people with diabetes when compared to the general population. Clarke still feels that health care professionals should counsel their patients about the risk of driving with hypoglycemia and the importance of measuring blood glucose before driving.

"If surveyed, I would bet that few [health care providers] ask the question regarding decisions to drive," says Clarke. "My personal experience has been that few patients, at least the ones I know, ever check their BGs before driving."

Symptoms of low blood sugar may include loss of judgment, shakiness, trembling, sweating, pounding heart, irritability, inability to think clearly, visual disturbance and lack of coordination.

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Categories: Blood Glucose, Blood Sugar, Diabetes, Drivers License & Pilot License, Driving, Insulin, Low Blood Sugar, Type 1 Issues

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Posted by Anonymous on 28 April 2008

in response to this idiotic comment:

Hoover adds that any effort to "blame the victim" for hypoglycemia-related motor accidents serves only to "misinform and to push the eventual solution just that much further out of reach."o this comment...

First and foremost driving is a priviledge not a right and my brother was killed by a hit and run diabetic driver in December of 2007. IF YOU CANNOT MAINTAIN YOUR VEHICLE IN A SAFE MANNER YOU HAVE ABSOLUTELY NO BUSINESS BEING ON THE ROAD RISKING YOUR OR ANY OTHER LIFE.

Posted by Anonymous on 28 April 2008

Yet another selfish comment:

I am a 28 year diabetic, my mother a 36 year diabetic, to quote my mother, "I will turn in my license when they (officials) get ALL the drunks off the road".


Michael Smith

Posted by Anonymous on 8 May 2008

Don't "blame the victim" says Joan Hoover. The DIABETIC driver who didn't take the proper precautions,and rear-ended ME,is not the Victim. I AM THE VICTIM. I was driving home from Work, (the thing I do to support my family) When a DIABETIC driver who was 35 miles past his destination, Hit ME. At over 100mph on the interstate. Totaled a '03 Mach 1 Mustang, and caused a compression fracture in my back. I AM THE ONE NOT ABLE TO WORK, I AM THE ONE ON PAIN MEDICATION EVERY DAY, I AM THE ONE NEEDING TO FIND A CAR, I AM THE ONE WHO JUST MIGHT BE THE VICTIM HERE. MAYBE?????????????

Posted by Anonymous on 2 September 2008

I completely agree with the Mustang driver hit on the highway-I don't care what your affliction or medical situation is...if you do not maintain your health and think you can control a 2 ton vehicle YOU ARE AN IDIOT. If you cannot control your health, do not keep appropriate foods or drinks in your car, do not test yourself before and while you are driving (not WHILE DRIVING OBVIOUSLY...) then you do not belong behind the wheel of a motor vehicle, take the damn bus, a taxi or move close to where you have to be. Now I'd like you to explain your motiviation for whining to my nephew who lost has father to a diabetic driver that slammed into his car at 65mph AND then backed up and drove away only to cause a second crash. It blows my mind that people can put their personal b.s. in front of the safely of the rest of us.

Michael Smith

Posted by Anonymous on 20 September 2008

My brother is diabetic so i see this from both directions. I do not see the diabetic as the victim if they haven't made absolutely sure their bg levels are ok before driving. I have been made aware of this as yesterday i was knocked off of my push bike and only survived by luck rather than the judgement of the 82 year diabetic who ran into me. After hearing his wife had known that he had done this before(not remembering afterwards) I think he should lose his licence.

Posted by Anonymous on 25 September 2008

If the man that backed into you had alcohol on his breath this would not be a topic...if you cannot drive safely then don't drive at all. THERE IS NO EXCUSE, PERIOD.

Michael Smith
San Diego

Posted by Anonymous on 10 November 2008

I totally agree with the comments Michael Smith has made. DON'T DRIVE IF YOU DON'T KNOW YOUR BLOOD SUGAR LEVEL--PERIOD!!!! I have type 1 (36+ years). About 8 years ago, I was involved in not one, but two accidents within a 6-month period of time. One of these times, I was on my way to visit my endocrinologist! (Talk about irony...........) Anyway, the bottom line is that NOBODY has the right to drive when they have diabetes unless they are 100% sure they will not harm anyone else (including themselves). All it takes is one reckless driver with diabetes who thinks he or she doesn't have to test and can just guess. It never works and I can thank God that I didn't hurt or kill anyone when I had those accidents. Don't be stupid--just realize that you can never be sure what your numbers are unless you test first. And by the way, I keep something in both of our vehicles (one of which I seldom drive) just in case I ever go low again. I also try to always have a meter with me so I can know for sure right where I am before I get in front of the wheel or at any time during a drive, after pulling over.

Posted by Anonymous on 10 November 2008

I have been Type I for 42 years. My only "complication" is hypoglycemia unawareness, which I believe is due to humulin insulin--never happened to me with beef/pork (but that's a different issue). I drive 100 miles a day, alone, on interstates and country roads. I test before I get in the car and after I get out. If I'm below 100, I drink juice.

Any diabetic that doesn't do that is a self-destructive idiot, and should be held fully responsible for any accidents they cause. Period. Dottie Love, Texas

Posted by Anonymous on 11 November 2008

If diabetics are to "Blame" _ (we do have some blame) then it ought to be mandatory for insurance companies to pay for Continues Glucose Monitors for those of us who must drive to work!!

Posted by Anonymous on 11 November 2008

I am a type 1. A couple of years ago I wrote off a work car because of low blood sugar. I strive for tight control (which has led to hypo glycemic unawareness) so I didn't even feel the hypo coming. By the time the paramedics reached me I was almost comatose. The only positive thing about the experience was that now I test BEFORE I get behind the wheel. And if I am below 4.5 mmol, I eat both a carb and a protein. And I make sure I test again a couple of hours afterwards. I don't feel my hypos coming. And I have kids. So I don't want to hurt them or anyone else's.

Posted by Tams on 11 November 2008

I am 34 years old and have had Diabetes for 30 years. I do believe that an uncontrolled diabetic should not be able to drive. What bothers me is, I am a controlled type 1 diabetic and I have gotten low while driving over the years. Some of the reactions have been very mild and others have been awful. Obviously, when I got into the car my sugar was fine or I wouldn't have gotten in the car. Things happen and being a diabetic and catching a low sugar isn't so black and white like the people writing comments are making it seem. I can leave the house with a perfect blood sugar and 45 minutes later I can be low. I realize that driving is a privilege and not a right and I am very sorry that people have lost their lives due to a diabetic driving while low, but I believe that this man obviously was very low and wasn't in control at the time to even know what he was doing when he hit, backed up and drove away. to be driving so erratically, he must have been quite low and lost his judgment. No diabetic wants to hurt an innocent person, let alone kill anyone. I am sure the Diabetic that lived after the accident is living his own hell after killing an innocent person. I can only speak for myself when I say I am responsible for ensuring I am capable of operating a motor vehicle in a safe manner. I do know what it's like to be behind the wheel and have a low come on very suddenly and not be able to react quickly enough. It's a terifying situation. But I find it difficult to read comments when people who don't have diabetes comment on how the diabetic should have acted, should have done etc. It's very easy to judge. But until you are a diabetic, experiencing what a Type 1 experiences, you have no idea...All Type 1 diabetic supplies should be covered by the healthcare system(I am in Canada)

Posted by oakhaven on 12 November 2008

As a Type 1 for 45 years I have experienced perilous conditions of hypoglycemia while driving. None, fortunately, has resulted in any kind of accident. Since over the years I am less likely to recognize hypoglycemic conditions it becomes critically important to know my glucose level before driving. It is dangerous for Type 1 diabetics to hop in the car and say "I feel fine and it's OK to drive". So, what do you do? (1) Test your blood glucose level just below you drive. (2) Determine adequacy of the glucose level. This is not as simple as saying "if 75+ I'm OK". Ask if you have active short-term insulin (e.g., Humalog) in you. How long ago did you take it? What have you eaten? Based on your answers you might need a BG level of 125 or 150? (3) If at all possible use the Medtronics or Dexcom continuous glucose monitoring system.

Posted by monopoly222 on 3 March 2009

Responsible Diabetics & Hypoglycemics Should Always Test Their Levels Before Driving

Daily Plan, Everyday

Test myself,
If levels are OK
Open the car door
Insert key
Turn car on
Put car in drive and get where I need to be. Safe and Sound for ALL!!!

Safety, For You, Me and Thee

Posted by Anonymous on 6 March 2009

My husband is a diabetic. The rule is that he always checks his sugar before driving. We know that he is not always aware of his sugar so he doesn't take chances. He has lost his licence in the past for medical reasons, uncontrolled diabetes. This was not because of any incident while driving. We had to jump through hoops to get it back again. He needed a six month period with zero lows. That is almost impossible! Losing his license also meant losing his job. We took a huge hit financially. We were very happy when he finally got his license back again after almost two years. Last winter, he was in a car accident. He had just left the hospital (where his blood was tested at the lab)and crashed less than two minutes down the road. There was a blizzard that day ( a record amount of snow). A few weeks later, the ministry of transportation tried to suspend his license again. They thought the accident may be caused by low sugar because my husband was a bit out of it when the paramedics arrived. He was out of it not because of low sugar but because the air bag knocked him out. We had to fight very hard for him to keep his license. We sent them weather reports and his glucose test results from the hospital a few minutes before the accident. His level was 15. If anything, that's HIGH not LOW!

Ever since it seems like the ministry is on a witch hunt for his license. Every couple of months they want all of his monitor results. Then they started questioning his eyesight. In Dec, we had to have many tests done on his eyes to meet their requirements even though his eye specialist informed them there was no problem with him driving. Now today we get another letter asking for even more testing on his eyes. We can't even find a doctor in our area to perform these tests! I almost think they made them up or something.

This is causing great stress in our life. My husband is being harrassed and he has done nothing wrong. We know the dangers of his disease and the risk of driving with low sugars.

Last year, I called the ministry to report my grandmother's horrible driving. She has diabetes. She is in her late 70's. She scares everyone in our family with her lack of driving skills. She does not drive with low sugar but is still all over the road as if she was drunk! She has been in many accidents and charged with reckless driving in the past. What did they say when I called? Unless the police stop her on the road and see a problem there's nothing the ministry of transportation will or can do. They said she'll have to go in for mandatory testing at 80 or 85? I say thanks a lot! Pray she doesn't kill someone in the meantime.

Posted by Anonymous on 2 December 2011

Who's the victim? I has hit by a car in the parking lot of Kroger's, while bent over putting groceries in my trunk; because a man had a low while driving. I have suffered for a year now. He was not ticketed for the accident. I was the victim. He hit me and my car, and drug the grocery cart return 30 feet thru the parking lot. Thank God my grandchild was not with me.

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