Which transportation system had the greatest impact on the United States in the period before the Civil War?

railroads

canals

turnpikes

clipper ships

Railroads had the biggest inpact because it delivers weapons and troops into battle

Railroads were far more effective at transporting goods across the country without the risk or delay that comes with sailing. Canals while effective weren't as speedy or reliable as a train since boats are rather fickle things. The turnpikes were being used by wagons and carriages that I doubt could compete with Trains!