Driving and diabetes - do you know your BG trend before driving?

I’ve been following with great interest the various discussions here about the legal and moral obligations of diabetics and the driving privilege. I noticed that many diabetics test their BG before getting behind the wheel of a car. That’s a good practice but is it enough?

My question here is this: Do you know which way your BG is trending before you drive? Is it going up or down? How fast is it moving?

Before I went on a continuous glucose monitor, I usually tested before driving but was sometimes surprised by a falling BG while driving. I’m thinking that doing a single finger-stick BG before driving is not enough information to make the driving decision. Maybe it would be much better to do two finger-sticks at least 15 minutes apart before driving in order to detect a BG trend.

What do you think?

Hi Dave,

Do you think that you’ll add driving as one of the situations that will trigger your 10-30 min apart BG testing?


I thought the same thing before I drive, so I test first and eat a little some thing if I am not a little high. High for me is above 100. Me Type 1 1 1/2 years and 54 male

You bring up a very good point…one test a trend does not make. To be honest, for most of the time w/ T1 I have only tested 1x before driving because I trusted I could feel my blood sugar dropping and adjust…now days, not so sure. I suspect these issues will only grow as T1s shoot for better and better blood glucose control. Luckily we have more technology to help us out. I have tried CGMS and was a little shocked to find that I was not feeling some of my lows…mostly at night though. With this new knowledge, I now test about 1/2 hr before driving, or doing anything were safety is an issue, and then right before…I also wear CGMS when I have them…have no insurance coverage for them right now. Ideal would be all persons w/ diabetes have coverage for CGMS and that they make them even more accurate so that we at least have the tools to prevent unnecessary accidents…would think this is something insurance companies and health care providers would get behind given cost savings. They are already working on the technology to have in-car readout from the CGMS and trigger to shut pump off until within range set. I am hopeful we will have more options as I get old and decrepit! Oh, that’s right…I am hoping for a cure before that;)


Your routine sounds safe and conservative to me.



You’re right – good control dances right at danger’s edge. Your habit of testing 1/2 hour and then right before driving is a good one – hard to remember to do in the real world – but I admire your caution.

My work shift ended at 11:30 p.m. tonight. As I got into my car and started it I heard: beep! beep! beep! My CGM was telling me that I had dropped below 80, to 79. I glanced at the Dex display and could see that the trendline was descending in a very shallow fashion. I tossed down 10 skittles, waited a few minutes, and then drove home. Nice to have a little back-up in today’s busy world!

Did you lose your insurance coverage? It’s too bad you can not get more sensors. What brand of CGMS do you use?

I remember thinking back in '84 when I was diagnosed, “They’ll find a cure for this in 20 years or so.” In some ways a cure seems no closer today than it was back then but in other ways there are some amazing breakthroughs being made. Thanks for the comment.

Love skittles:) and Smarties. So glad you have the Dex…I use the MM because I got it w/ my pump (MM522), but I am hoping to try the Dex end of month…see my Endo and Diabetes Educ. I appreciated the info I got from the MM, wondering if the Dex will be more accurate for me…before I make the decision to pay for most of it myself.

I had a great job w/ great insurance (worked for a teaching hospital), but then this economy happened and I was “downsized”…I now maintain insurance by going to grad school. For those who need it…it usually is about the only place you can get insurance as part of a pool of people…without working for them. It has been a lifesaver! but, only covers 80% of anything and only $1000 of durable equipment…so, falls way short of my needs. I have done everything “crafty” to stay on the pump and even to try the sensors. I am pretty certain that I will get the Dex and that they may pay for it…but, not the supplies this year. I am really hoping for some healthcare reform that would ensure more complete coverage for all the money spent…much like waiting on the cure, me thinks:)

I bet we have traveled a similar road…I was diagnosed a little bit before you and remember going to conferences in my 20’s when they said…“just right around the corner”. I am of the thinking now, that we really need to demand it…technology and knowledge could be there to cure it…just not a lot of incentives. Transplants are not a cure to me…something like what Faustman is working on…could be. So…let’s continue to dream. Be well, my friend:)


I realize that we’ve wandered a bit off topic but sometimes it’s the side conversations that inform the most.

Your use of grad school to get health insurance is unusual but effective. In today’s economy you have to be resourceful. You mentioned that your policy only covers $1000 of DME. Are sensors and pump supplies considered part of that $1000? Is that $1000 per year?

When I’ve changed pumps and was left with a surplus of unneeded supplies, I found someone without insurance and desperate for supplies and I just donated them. I wish there were a network of sorts that could coordinate that kind of activity.

I just became aware of the Faustman research recently when it was referred to here at TuD. I followed the links and was surprised at the hypothesis of her effort. I had always thought that there was no scientific doubt that my pancreatic islet cells were dead and gone. Now Faustman thinks that if we could only rid the body of the defective immune system cells then the pancreas will fix itself! That’s amazing and hopeful. Unfortunately any fruit of her effort is again out on the 8-10 year horizon. I don’t have too many 8-10 year horizons left.

Please post about your Dex experience, even if you only take a 7-day trial. By the way, if that happens, there’s a good chance that you could push that to 14 days. If you haven’t seen this yet, check out Wil Dubois’ December 3 and 8 entries. These are about his trial run on the Dex after many years with the MM CGMS. Here it is: http://lifeafterdx.blogspot.com/


Michael, the moderator of www.insulin-pumpers.org does a very good job of receiving and then distributing unneeded pump supplies. Unfortunately most of the supplies he receives are for older model pumps, because most people on new pumps are not getting rid of supplies. But it is definitely a place to send supplies you’re not going to use and ensure that someone else will use them.

Thanks, Lathump. I was not aware of this.

Yes, I absolutely know my trend before I drive. As a normal part of control we must also do everything possible to prevent downward trends. I do a 1400 mi drive twice a year + other trips + all the driving for an active life of two retired people who like to be in the car and see and do things. I’m on 4 meals a day, take low carb, have very low amounts of insulin. My Lantus is balanced all day at 100. I take readings q 30 min to 1 hour on all drives including those in suburbia, cross country and urban areas. There’s always a way off the interstates and tollways if need be. There is no substitute for knowing where one’s mg/dl is, and if one is headed downward. I prevent any downward trend by glucose tabs and they’re within quick reach of both me and the passenger. One needs to know exactly what grams will do what.
I do think that some who have diabetes need more frequent testing than I have to do (7 a day). I think each one using high carb, high doses of insulin, swinging from high to low and back, needs profit from wearing a CGM for more than a short trial. I’m an avid lover of them. Anyone with hypoglycemic unawareness should have one all the time, at least until he has figured out how to prevent any downward swings.

Leo – You’re control sounds excellent. You also seem very tuned into where your BG is and where it is trending. An adherence to this type of protocol puts the driving safety aspect of a diabetic on par with non-diabetics.

I’m interested in moving toward a lower carb diet myself. Can you recommend information or book that would be helpful? Thanks.


i have to admit i rarely test before driving. i’ve been t1 for 50 years and never had a seizure, never been incapacitated by a high or a low and i have no complications. one reason is my life is pretty regimented and i test a lot as a matter of routine. so … if i’m driving around town i generally have a good idea of my BGs without testing. if i’m going on a longer trip i definitely test; sometimes while driving. (which raises a whole different question about the dangers of TESTING while driving.)

also … i am pretty resilient to low BGs. i’ve driven when i’m in the 40s and been fine. wouldn’t recommend it and i don’t do it intentionally but on occasion i’ll come home after driving somewhere and test.

about the ``40s’’ … it doesn’t happen often and, after 37 years driving as a T1 with no accidents are tickets i’m comfortable with my approach. but … in this specific case i was coming home from work. walked from the subway to my car and drove the regular route of four miles. it’s not the preferred approach to be sure, but my ability to perform while low-ish has been well documented.

I’m a type 2 I test everytime I leave the house to goes somewhere. If my BS is close to 100 I eat something to push it up. I have had it drop while driving and I nodded off but something brought me out of it before anything happened that was before I was dx’d its a mistake I won’t make again.

DC Reporter,

I know what you mean about the lack of impairment sometimes when BGs are very low. When my BG drops below 45 or so I often suffer verbal impairment, that is I have difficulty stringing words together to make a sentence. I’m one step away from complete incoherence.

Every once in a while, however, I test, find I’m at say 39, and I don’t feel incoherent at all. In fact I’ve found an increase in my useable vocabulary! I’ve been engaged in conversation when I test. When I discover how low I am I’ve asked the person I was talking to if I displayed any changes in personality or exhibited any deficiency in my usual ability to maintain appropriate conversation. In these cases my conversation partner has always responded “no.” They are as much surprised by the measured low as I am.

Maybe this is what “hypo unawareness” is all about. Maybe cognitive ability sometimes does not become impaired until you suddenly drop off the cliff into complete incoherence quickly followed by a seizure. Maybe some hypos are much different than others. This would account for the “sneaky” lows that stalk all of us T1s from time to time.



I’m pretty ignorant when it comes to T2 symptoms and blood sugar ranges. When you go “low,” what kind of numbers have you measured? What kind of symptoms do you experience?

I think that your habit of testing every time you leave the house is a good one.


DC Reporter,

Your 50 years of fighting this beast successfully impresses me. It’s a formidable foe that has taken down many good people.

I’m hesitant to offer any advice to someone with as much experience as you but I think you would do yourself a favor to find out your BG level and trend before you drive. It’s a small task and it only takes one serious low to harm you and others around you.

Keep on keeping on!

Thanks Terry for the additional info on the Dex. I get about 7 days on the MM sensors…looking forward to comparing to the Dex. I read a research article in which they compared the Dex and MM simultaneously…and in comparison to lab tests…on the same test subjects. The Dex7+ looks like it will be the one…but, want to do a comparison for myself.

Yes, unfortunately I only have $1000 of DME/year ($100 deductible) and a replacement pump, pump supplies would come out of that amount. They said I could use any leftover medication coverage ($1,200/year) for pump supplies…but, I would not have anything left over:) I thought I at least had coverage for a new pump…as mine was off warranty, but that was when I found out how low my DME coverage was…and had to fund a new pump myself. I asked other grad students here on Tu what their coverage was like…many others have full medical coverage similar to what I had working…but, each university is different. I am grateful to have the coverage that I do, for a very reasonable price…compared to high risk pools. Goal is to finish the grad work and start teaching as soon as able.

You should consider getting screened for the Faustman study. I am pretty sure they want long standing D’s that are fairly healthy (cardiac, kidney, etc.). I am taking the trip up to Boston in Sept to give my blood donation…first step in getting in on the trials. I too have lived w/ this a long time and anything promising is worth the trip…plus I used to live in Boston and have lots of friends there:) I really hope Phase II shows promise and brings the cure w/in reach.

Be well Terry:) and thanks for your posts.

Makes me think…why do we not have a place here on Tu where folks can say what they need or have and then others can hook up w/ them? I will email Manny.