Answer to Question #11814 Submitted to "Ask the Experts"

Category: Micro/Radio Waves, Radar & Powerlines — Microwaves and Radiofrequency

The following question was answered by an expert in the appropriate field:

Q

Are there radiofrequency (RF) safety concerns associated with the radar units in "assisted-driving" or "self-driving" vehicles?

A

Automobile radar used to measure the distance and speed of objects in front of a vehicle typically operates at about 77 gigahertz (GHz)—in the millimeter (mm) wave band—and at RF power levels of a few tens of milliwatts (mW). In view of the low power level of automobile radar and the shallow penetration depth of the energy into the body (less than 1 mm), it seems unlikely that these units could pose a health risk.

As with other devices that transmit RF energy in the United States, automobile radar must comply with RF exposure limits of the U.S. Federal Communications Commission (FCC); other countries have similar regulations. I looked up FCC test data for several such devices, and all report RF exposure levels that are far below the FCC limit of 10 watts per square meter (W m-2) measured at a distance of 20 centimeters (cm). Also, because the transmitted power levels are so low, it is hard to imagine how the cumulative exposure from radar sets in a number of automobiles in the same vicinity might approach or exceed FCC limits.

While there has been little research on possible health risks of millimeter waves, health agencies have not expressed concern about possible health risks at exposure levels far below major international standards (which are generally similar to FCC limits).

For a useful reference see the Clemson University Automotive Electronics website.

Kenneth Foster, PhD

Answer posted on 27 December 2016. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.