Salt water and tap water which one freezes faster?

fresh water freezes at a higher temperature so should freeze before salt water. This is because when you dissolve substances in water you get freezing point depression this is where they need colder temperature to freeze. So this is why things like jam, vodka won't freeze in most home freezers even though they contain alot of water they also have alot of dissolved substances. Also why salt is spread on roads to melt the ice.