DOT color vision requirements for commercial drivers

Updated November 2026

Commercial drivers in the U.S. must meet the vision standard of the Federal Motor Carrier Safety Regulations. Color vision is part of it, but the rule is narrower than many drivers expect: you need to recognize traffic signal colors, not pass every plate of a color vision test.

This page is general information, not medical or legal advice. The medical examiner makes the decision.

What the rule says

49 CFR 391.41(b)(10) requires, among other things, "the ability to recognize the colors of traffic signals and devices showing standard red, green, and amber."

The same paragraph also sets the other vision requirements:

distant visual acuity of at least 20/40 (Snellen) in each eye, with or without corrective lenses,
distant binocular acuity of at least 20/40 in both eyes, with or without corrective lenses,
a field of vision of at least 70 degrees in the horizontal meridian in each eye.

Who checks it

Color vision is checked during the DOT physical by a medical examiner listed on FMCSA's National Registry of Certified Medical Examiners. A driver who meets the standards gets a medical examiner's certificate and must carry it when on duty (49 CFR 391.41(a)).

Which tests the examiner can use

FMCSA's Medical Examiner's Handbook (2024 edition) lists Ishihara, pseudoisochromatic, yarn or Farnsworth tests. The examiner can also use a controlled test with standard red, green and amber, for example the colors on a Snellen chart.

Can you drive with color blindness?

Often, yes. The handbook says that if a person can recognize standard red, green and amber, they meet the minimum standard, even if they have some type of color perception deficiency.

A driver who cannot recognize the colors of traffic signals and devices showing standard red, green and amber is not physically qualified. The alternative vision standard in 49 CFR 391.44 is for drivers who do not meet the acuity or field of vision standard in one eye. It does not replace the color requirement.

This is also why a failed online screening does not automatically mean you will fail the DOT physical.

Where an online screening fits

An online color vision screening, including the free test on this website, is not part of the DOT physical and does not replace it. It can still help as a private pre-check:

Drivers can see in advance whether the examiner may want to look more closely, and visit an eye care professional first if they are unsure.
Fleets and driver staffing agencies sometimes add a pre-check after the conditional job offer, so candidates who may need an eye exam can book it before the DOT physical. The DOT physical stays the decision.

Frequently asked questions

Can I get a CDL if I am colorblind?

Possibly. The DOT rule asks that you recognize standard red, green and amber, so many drivers with a mild color vision deficiency meet it. The medical examiner decides.

Does the DOT use the Ishihara test?

It is one of the tests a medical examiner may use. Others are pseudoisochromatic plates, yarn, Farnsworth or a controlled test with standard red, green and amber.

Does the online test on this site count for my DOT physical?

No. Only the medical examiner can decide. Use the online test as a private pre-check.

What happens if I cannot recognize the signal colors at the DOT physical?

You are not physically qualified under 49 CFR 391.41, and the alternative vision standard does not change that. Rules for driving only within one state can differ, so ask the examiner or your state licensing agency about your options.