is a yellow speed limit sign a suggested speed
Advisory speed limit The signage for advisory speed limits is not defined by the Vienna Convention on Road Signs and Signals, and is therefore not standardised internationally. The United States uses a small yellow sign under the main warning sign, as well as a standalone variation on the standard speed limit sign, with a yellow background instead of a white one, the words "speed limit" omitted and an additional panel stating the type of hazard ahead. Though they list speeds, the U.S. advisory speed signs are classified as warning signs, not regulatory signs, as primary speed signs are.[6] Australia uses a similar design as the U.S. in spite of regulatory speed limit signs being quite different. Germany used a square sign with a blue background and white lettering, similar to the minimum speed limit sign,[5] and New Zealand uses a yellow background with black lettering (similar to the Australian design without the "km/h" lettering). The United Kingdom currently uses an oblong white rectangle with black lettering stating "Max Speed".
Speed limits in the United States The highest speed limits are generally 70 mph (113 km/h) on the West Coast and the inland eastern states, 75–80 mph (121–129 km/h) in inland western states, along with Arkansas and Louisiana, and 65–75 mph (105–121 km/h) on the Eastern Seaboard. Alaska, Connecticut, Delaware, Massachusetts, New Jersey, New York, Puerto Rico, Rhode Island, and Vermont have a maximum limit of 65 mph (105 km/h), and Hawaii has a maximum limit of 60 mph (97 km/h). Washington, D.C. and the U.S. Virgin Islands have a maximum speed limit of 55 mph (89 km/h), and Guam and the Samoa have speed limits of 45 mph (72 km/h). Unusual for any state east of the Mississippi River, much of I-95 in Maine north of Bangor allows up to 75 mph (121 km/h), as well as up to 600 miles of freeways in Michigan. Portions of the Idaho, Montana, Nevada, South Dakota, Texas, Utah, and Wyoming road networks have 80 mph (129 km/h) posted limits. The highest posted speed limit in the entire country can be found on the Texas State Highway 130, and it is 85 mph (137 km/h).