When sampling uncompacted roadway materials, how far should the roller stay from the sampling operation?

• A. At least 15 ft away from the sampling operation
• B. At least 5 ft away from the sampling operation
• C. At least 10 ft away from the sampling operation
• D. There is no minimum distance

Answer: (C)

When sampling uncompacted roadway materials, you want to avoid any disturbance from the roller that could change the sample you’re trying to collect. The material hasn’t been rolled yet, so the roller’s weight, vibrations, and movement could compress or shift it, making the sample non-representative of what was placed. Keeping the roller at least ten feet away provides enough space for the sampler to work and reduces the chance that the roller will affect the sample or interfere with the sampling operation. Closer than ten feet increases the risk of disturbing the material and compromising the test results, while a distance greater than ten feet isn’t necessary for safety if the minimum is met.