In Frogger, you move your frog one square at a time in a cardinal direction and attempt to make it to the safe green grass without getting hit by any cars or falling in any blue water on your way. In this puzzle, the cars loop around the screen, so as soon as they go off of one side, they come back around on the other.
It's okay if the cars whiz by you as you're in midair hopping! As long as every hop starts and ends on a safe spot and you don't try to hop over any cars along the way, you'll be okay. Since everything's moving twice as fast as you, your first move is to hop straight forward between the two trucks.
The only way to make it through each river is to hop on the back of a turtle, so make sure you're keeping track of where they are! Remember that you leave the ground as soon as you land on it, so you will not get dragged along with the current at all when you land on a turtle. It may be useful to keep track of the positions of everything with a spreadsheet or physical items. Notice that the state of all the cars and turtles repeats every nine moves.
Remember that the letters are painted on the ground, so they don't move with the cars! The final answer is made up of each letter you hop on in order, but you don't count letters that you've hopped on previously. The existing words like "TAKE COVER" don't actually mean anything; they're just for fun.
It will take nine moves to hop off of the back of the first turtle, and it will take nine more moves from there to hop off the back of the second turtle, meaning when you start each new section of road, the cars are all exactly as they were at the beginning.
In the final stretch of road, one of the moves will require hopping back onto the second turtle before continuing on to reach the third turtle. Don't forget to count the final letter on the green grass!