sometimes the speed limit is different depending on which way you are traveling. It was explained to me that if you came off of a road with a 45 mph speed limit and traveled down another (lets call it road X) and even though there may be no signs, the speed limit of the road you just came off of is still in effect. Now if you came from the other end of the road off of a 55mph limit roadway, your speed limit on road x is now 55mph unless otherwise marked. Sounds screwy to me but thats how it was explained to me by some local cops