More than 6 million drivers operate commercial vehicles in interstate commerce. Federal Motor Carriers Safety Regulations (FMCSRs) require most of these drivers to be certified by a medical examiner.¹ The physical examination to comply with these federal regulations, commonly called the DOT (Department of Transportation) examination, is one of the most frequently performed ambulatory procedures. However, training in performing this examination is rarely offered, and concise guidelines are seldom available.

Incompetent performance of the DOT examination can result in physician liability. In one court case,² a physician was found negligent for certifying a driver who was blind in one eye, had very poor vision in his other eye and had previously been rated 100 percent disabled due to multiple physical impairments. This driver was involved in a fatal accident that probably would not have occurred if his vision and reaction times had been normal.

While negligent DOT medical examinations have only rarely resulted in accidents and lawsuits, inattention to detail during these screening procedures may not be that unusual. The authors of this article have noticed that many drivers are surprised when they receive a more than cursory certification examination. This is indirect evidence that their previous medical examinations may not have been thorough.

In 1992, the FMCSRs were amended to allow physician assistants, advanced nurse practitioners and chiropractic physicians to perform DOT certification examinations, provided that their state license permits them to carry out examinations of this type. All examiners who perform these examinations should be familiar with the conditions that preclude driver certification, and they should be prepared to deal with common medical problems, such as hypertension, diabetes mellitus, and vision and hearing deficits. It should be emphasized, however, that any condition can be disqualifying if it is severe enough to affect the driver's ability to operate a motor vehicle safely.

The cases summarized in this article illustrate sections of the regulatory requirements and provide guidance for discussing potentially disqualifying conditions with drivers.

Guidance from the Federal Highway Administration

Most primary care physicians are familiar with the physical examination form published in the FMCSRs. This form, which contains brief instructions for performing the certification examination, is used almost universally, even though it was published only as an example. Physicians may devise their own examination form if it covers at least the same information as the published form.

The FMCSRs also list 13 conditions that can disallow driver certification. Four of these conditions always require denial of certification: insulin-treated diabetes mellitus, seizure disorders, significant vision deficits and significant hearing deficits. The 13 sections of the regulations are summarized in Table 1.^1,3–8 Detailed regulatory criteria statements on each of these conditions are available from the Federal Highway Administration (FHWA).

Reports from expert panels^3–8 provide the most comprehensive advice on performing the DOT certification examination, the situations requiring additional tests and the conditions for which disqualification is required or recommended. These reports cover many cardiac, pulmonary, neurologic, psychiatric and diabetic disorders, as well as vision and hearing deficits. The cardiovascular report³ covers valvular heart disease, congenital heart disease and arrhythmias, as well as numerous other disorders. The report on neurologic disorders⁴ addresses cerebrovascular problems, headaches, vertigo and dementias. Compared with the FMCSRs, which provide general guidelines, the DOT expert panel reports recommend disqualification for a wide variety of specific disorders.

The text of the DOT monographs and other FHWA regulations can be obtained from the National Technical Information Service and through the Internet. If information about a specific problem is not available, physicians may contact the FHWA. Several resources for physicians are listed in Table 2.

Physicians' Approach to the DOT Examination

In performing the DOT medical certification examination, physicians and other examiners should remember that their primary responsibility is to the public—not, as in the usual office visit, to the patient. The intent of the DOT examination is to detect physical or mental defects of “such a character and extent as to affect the applicant's ability to operate a motor vehicle safely.”¹ Therefore, the examiner should be prepared to decline, defer or limit the duration of certification if significant questions are raised about a driver's ability to operate a commercial vehicle safely.

One case series of 526 DOT certification examinations^9,10 found that 22 (4 percent) commercial drivers had diabetes mellitus and 23 (4 percent) had blood pressures above 160/90 mm Hg. Furthermore, 44 (8 percent) of the drivers were receiving medication for hypertension, and 18 (3 percent) had a history of a major cardiac event, such as bypass surgery, angioplasty or arrhythmias.

Based on this case series and the experience of the authors of this article, approximately 5 to 10 percent of drivers may initially be denied certification pending the results of additional studies and/or verification of medical records. Although very few drivers are ultimately denied certification, examiners should remember that investigators will almost certainly review the records of the certification examination following any significant motor vehicle accident involving a commercial driver.

Declining, Deferring or Limiting Certification

Allowing a therapeutic trial of driving for a person with a serious medical condition is not an option. This point is a particularly important one for physicians or other examiners who may be asked to certify their own patients with known medical problems. In certain situations, it may be necessary to tactfully decline to perform a certification examination. Alternatively, examiners can defer certification until disqualifying conditions are corrected or brought under acceptable control.

Illustrative Case 1: Declining Certification for a Disallowed Medical Condition. The driver has insulin-treated diabetes mellitus. The examiner says,“I'm sorry, but you cannot take insulin and be certified for driving. The safety risk is just too great, and certification is against federal regulations.”

Illustrative Case 2: Deferring Certification for a Correctable Vision Problem. Wearing glasses, the driver has a distant visual acuity of 20/40 in one eye and 20/70 in the other eye. The examiner says, “You need 20/40 vision in each eye. I think you probably need new glasses. We can finish the rest of the examination and complete the paperwork if new glasses correct your vision.”

Occasionally, a driver's desire to remain certified can provide a strong incentive to comply with needed medical treatment. Medical examiners have the option of limiting certification to any length of time less than two years. If, for example, the physician has questions about the driver's compliance with needed treatment, limiting the duration of medical certification to one or two months at a time can be an extremely useful option. Hypertension, diabetes mellitus and pulmonary diseases are conditions for which certification might be limited.

Illustrative Case 3: Limiting Certification for a Chronic Condition. A driver has a blood pressure higher than 200/110 mm Hg. He has not been compliant with antihypertensive drug therapy in the past. After he has taken medication for a week, his blood pressure goes down to 158/86 mm Hg, and he requests DOT certification. The examiner says, “Your pressure is under control now, but it has been erratic. I will certify you for only two months at a time to be sure that your blood pressure stays under control. If your blood pressure remains under control, we may be able to get you certified for a longer time.”

Practical Aspects of the DOT Examination

Screening

Most disqualifying medical problems are identified during initial screening. A nurse or experienced office assistant should obtain a brief history, take vital signs and record any medications the driver is taking (Table 3). Only a few minutes are needed to inquire about the most common and important disqualifying conditions, which include problems with blood pressure, vision, hearing and cardiopulmonary fitness (Table 1).

Illustrative Case 4: Deteriorating Color Vision. A driver with type 2 (non–insulin-dependent) diabetes mellitus previously did well on the color discrimination vision screening test. Now he has trouble with red-green discrimination. The examiner says, “Your color vision is not as good as it was last time. I think it's time to see an ophthalmologist and find out what is causing your vision to deteriorate. I also want you to return tomorrow for fasting blood sugar measurements.”

Illustrative Case 5: Hearing Problems. A driver fails the whispered voice test. When tested with a recently calibrated audiometer, he has a hearing loss of more than 40 dB in both ears. The examiner says, “First, we will recheck you in two weeks to give you some time to get over this cold. Then we will test your hearing again after you have had a quiet weekend. If your hearing is still this bad, you'll need to wear a hearing aid to be certified.”

Illustrative Case 6: Borderline Hypertension. On the day of the DOT examination, a driver's lowest blood pressure is 165/95 mm Hg. The examiner comments, “Your blood pressure is high. We need to recheck it over the next few days. If it is lower, you can be certified. If it remains elevated, we can give you a three-month certification while you get your blood pressure under control. Here is some information that will explain what you should do” (Figure 1).

Medical History

Although the medical history is probably the most important component of the examination process, it is often neglected. Even if a driver reports no problems on the history section of the examination form, the physician should inquire about significant medical conditions. This is especially important when the physician is unfamiliar with the driver being examined. The physician may ask the following questions: “Do you have any medical problems? Are you taking any medications? Are you under a doctor's care for any reason? Have you ever had a seizure, passed out or lost consciousness?” If the responses to these questions raise any concerns, the physician should obtain a more thorough history and perform a more targeted examination.

Physicians who design their own examination form might include a comprehensive history section with a space for the driver's signature. If a driver is asked directly about specific health problems and is then required to attest to the accuracy of statements, he or she is likely to disclose information that otherwise might not be offered. This approach may also provide some protection for the examiner should legal challenges arise.

Illustrative Case 7: History of Myocardial Infarction. A driver recalls having had a myocardial infarction only after he is specifically asked about this heart problem. He states that he did not see a question about myocardial infarction in the history section of the examination form. He has, however, had no problems for over six months and has recently seen his cardiologist. The examiner responds, “I think you may be certified, but I need to review the results of the treadmill test you took last month and get a letter from your cardiologist stating that you are cleared to drive.”

Physical Examination

With completely healthy, young drivers, the physician component of the examination may take less than seven minutes. The physician should review the history and screening test results while observing the driver as he or she sits, stands and moves around the examination room. If the physician notices that the driver has a gait or coordination problem, additional questions should be asked and a more targeted examination should be performed. Generally, however, the physician should be able to perform a basic physical examination according to the protocol presented in Table 3. In addition to a review of the history and screening tests, emphasis should be placed on auscultation of the heart and lungs, the findings of common neurologic tests and a determination of musculoskeletal system integrity. Less emphasis generally should be given to the genital, urinary and digestive systems, which are unlikely to cause safety-related problems. Of course, the physician should remember that any medical disorder or combination of disorders and risk factors can be grounds for the denial of certification if the overall condition of the driver is severe enough to affect the safe operation of a vehicle.

Need for Additional Objective Information

In deciding when additional testing is required, the physician should consider two factors: (1) the potential of the condition to cause sudden loss of consciousness or loss of control and (2) the presence of additional risk factors or target organ damage that can aggravate the condition.

In addition, the physician might double-check his or her own judgment by considering the following questions: “Is this driver with multiple risk factors and an irregular pulse at high risk for sudden loss of consciousness?” and “Would I want my children to ride in a bus this person is driving?” In short, if any condition or combination of risk factors causes concern, additional objective information and/or clearance from a specialist is appropriate.

Appropriateness of Tests

The role of the physician in the DOT examination process is not to “diagnose” but to determine if the driver can operate a vehicle safely. Thus, diagnostic tests generally should not be ordered if functional tests show that a driver has the capacity to operate a vehicle safely. For example, a radiograph probably does not need to be obtained for a driver with a painful shoulder if range of motion, reaction times and strength are normal.

Certain medical problems almost always warrant additional tests. For example, a fasting blood sugar or glycohemoglobin level should almost certainly be obtained in an obese driver with urine dipstick findings of 2+ glucose and 1+ protein. Pending evaluation, this driver should be certified only temporarily, if at all. Pulse oximetry, pulmonary function tests and arterial blood gases should be considered if a driver's pulmonary status is in question.

Obtaining Clearance from a Specialist

When a driver has a disorder that is outside the examining physician's area of expertise or zone of comfort, clearance from a specialist may be prudent. It is not appropriate to use specialists to “clear” drivers with disorders that the initial examiner already knows to be incompatible with safe driving. Rather, the role of the specialist is primarily to clarify questions involving borderline or complex cases.

Following most significant cardiac events, such as a myocardial infarction, an invasive cardiac procedure or a serious rhythm disturbance, a driver almost always should be cleared by a cardiologist.^11,12 A driver with a disorder that has significant effects on the neurologic or musculoskeletal system may need to be cleared by a neurologist or a physiatrist.^13,14

Illustrative Case 8: Abnormal Neurologic Findings. A driver known to the examining physician presents with a positive Romberg test, a slightly ataxic gait and nonreactive pupils that were not noted on previous examinations. The examiner says,“These tests show an abnormality that could affect not only your driving but also your health. I'll have my nurse make an appointment for you with a neurologist. These test findings need to be evaluated, and the problem must be corrected before you can be certified.”

Illustrative Case 9: Asthma or Chronic Obstructive Pulmonary Disease. A driver with steroid-dependent asthma has been seen in an emergency department for exacerbations of asthma twice in the past six months. He is wheezing, and his pulse oximetry shows 93 percent saturation. The examiner responds, “Your asthma needs to be better controlled before you can be certified. A pulmonary specialist may be able to set up a more effective treatment plan, so that your condition is not so fragile.”

In most instances, the physician who notices a potentially disqualifying condition in a driver should complete the remainder of the examination pending final disposition. Certification, however, should not be given until all questionable findings have been adequately addressed.

Special Situations

It is not uncommon for physicians to be caught in uncomfortable situations during the course of certification examinations. For example, an unemployed driver may lose a desperately needed job if he or she cannot be certified by the next day. The examination may suggest that the mental status of an older driver with years of safe vehicle operation may be deteriorating. In other instances, medical opinions may differ concerning what constitutes reasonable control or follow-up for hypertension or type 2 diabetes mellitus.

Unfortunately, the regulations and supporting literature do not provide firm guidance for every set of circumstances. In the final analysis, public safety is the most important consideration in a DOT certification examination, followed by the driver's health.

Illustrative Case 10: Responding to Objections. A driver had a thromboembolic stroke three years ago and has residual hemiparesis. After the stroke, he was certified by another physician, and he now demands recertification. The examiner responds, “I am sorry, but the Department of Transportation held a conference of experts to discuss conditions like yours. The experts concluded that such conditions are not compatible with safe driving. If you have an accident, both you and I would be held accountable.”

Diabetes Mellitus

Dealing with a driver who has diabetes mellitus but does not use insulin is particularly difficult, because treatment guidelines clearly call for tight control of blood sugar levels¹⁵ (Table 4).¹⁶ However, tight control substantially increases the chance of hypoglycemic reactions (Table 5). Newer oral medications for diabetes may cause less hypoglycemia while still controlling blood sugar levels. Use of these medications should be considered in diabetic drivers who might not otherwise be allowed to operate a commercial vehicle due to hypoglycemic symptoms.

The examining physician must carefully consider the severity of a diabetic driver's condition, the driver's compliance with treatment, the extent of target organ damage and the risk of hypoglycemic reactions (Tables 4¹⁶ and 5). Public safety and treatment should take priority over the certification of a driver with poor glycemic control, multiple risk factors and target organ damage. Deferring or limiting certification might be considered for the diabetic driver with minimal risk factors who may benefit from incentives for getting appropriate treatment and achieving better glycemic control.

Waivers

Waivers allow drivers to be certified for interstate driving when they have physical defects that ordinarily would be disqualifying conditions under the FMCSRs (e.g., amputation of a hand or foot). A driver must apply to the FHWA for the waiver.

Certifying a driver with a waiver requires special vigilance, because the regulations covering waivers are somewhat complex, and relatively few waivers are granted. The driver should provide the examining physician with complete and current documentation of the waiver and copies of the applicable regulations. A rarely used part of the examination form and the driver's certificate must be checked following the examination, provided that the waiver and all other aspects of the examination are in order.

Each state has its own rules and regulations for licensing and certifying drivers who operate vehicles intrastate (i.e., within a state and not across state lines). Most states provide waivers for certain medical conditions that would ordinarily disqualify drivers from operating vehicles under FMCSRs. For example, most states provide waivers for certain drivers who use insulin to treat type 2 diabetes mellitus, but the waivers are only for intrastate driving. The physician who performs DOT examinations should be careful not to certify a driver for interstate driving (across state lines) when the waiver is intended only for intrastate vehicle operation. Writing “intrastate” on the DOT card is not acceptable.

Fortunately, waivers for both interstate and intrastate driving are rarely encountered. With any driver who has a waiver, the examining physician should insist on complete and thorough documentation to be certain that all federal and state regulations are followed.

Future of DOT Certification Examinations

The present system for certifying and employing commercial drivers appears to do a reasonable job of protecting the public. Nonetheless, evidence exists that a significant number of examinations are performed incorrectly. The FHWA is considering a number of measures for improving the quality of the examination. Possible measures include the following:

1. A registry that would permit the DOT examination to be performed only by examiners who have received a copy of the standards and all supporting materials.

2. A mechanism to ensure that unqualified drivers are not able to find an examiner who will qualify them without additional review of the difference of opinions.

3. A revised form that will include the regulatory criteria, an enhanced medical history portion and more complete instructions on the medical standards. Proposed changes will be published in the Federal Register. Many competing interests will have to be taken into account before any new rules become final. It is uncertain which, if any, of the above changes may be implemented.

Final Comment

Before granting medical certification, the examining physician should be sure that the driver's history, physical condition and all other available information are consistent with the safe performance of his or her duties. If the physician has significant questions about a driver's condition, additional objective data must be obtained and, if necessary, certification should be denied, deferred or limited. As a practical matter, it is the driver's responsibility to provide test results (if tests were performed elsewhere), clearances from specialists and documentation for waivers. All supporting evidence and data should be filed with the DOT examination form and retained like any other medical record.