New York has one of the most extensive and one of the oldest transportation infrastructures in the country. Engineering difficulties because of the terrain of the state and the unique issues of the city brought on by urban crowding have had to be overcome since the state was young. Population expansion of the state generally followed the path of the early waterways, first the Hudson Riverand then the Erie Canal. Today, railroad lines and the New York State Thruway follow the same general route. The New York State Department of Transportation is often criticized for how they maintain the roads of the state in certain areas and for the fact that the tolls collected along the roadway have long passed their original purpose.