The accuracy of a variety of instruments that might be suitable for field measurement of nighttime sign surrounds was evaluated by comparing measurements made with them with measurements made with a laboratory-quality telephotometer. A technique for the evaluation of surrounds that identifies them by luminance measurements was developed. The measurement of numerous surrounds leads to the conclusions that conventional descriptions are often in appropriate, that opposite sides of the same roadway may vary inluminaire intensity, and that roadway geometrics may cause variations in surrounds. Photographs and luminance values that represent four generalized luminance levels and a description of each are given.