Heading East from Hwy 146 There is a 2 mile section at 55 mph, as you cross Gum Bayou into the City of Dickinson the speed rapidly drops to 40 mph. This however is on a 4 lane hwy in the country. If you do not know the speed change is there you most likely miss it. You are then charged with going 55 mph in a 40 mph zone. Out of towners often take FM 517 as the shortest route from the restaurants on Galveston Bay to I 45 which brings them home Houston and the surrounding area. The speed trap makes them a prime target. If the town were truly concerned with the safety of the people within their city limits due to speed, they would put up a flashing yellow light and reduce speed sign.