Scratch Lv.2 Racing game

How to play: Press the green flag to start the game, and press the W key to start moving. The A and D keys steer the car and pressing the W key more increases your speed. Light green grass slows down your car while the dark green parts cause you to spin out. You must complete 3 laps to win.
Game Link: https://scratch.mit.edu/projects/186979648/#editor

Questions: 1) A difficulty I ran into during programming the game was making the grass interact with the car in a way that I wanted. When I started, I wanted the grass to be like a wall preventing the car from touching anything outside of the track. However, I couldn't find a way to successfully do it so I just made the grass slow the car ( like Mario cart).
                  2) I added a few changes to the tutorial, that changed the way that the game would be played. First, I changed the track  layout because I thought the tutorial`s track was too easy to complete (Just pressing one turn direction). That reason caused me to change the layout to the one you see above to make the game more difficult. To do this, I just drew the track in a different way than the tutorial (using the paintbrush tool) Secondly, I changed the way the grass worked. This was because I felt like the way the tutorial guy made the grass interact with the car was way too unforgiving, as the car would lose all speed and come to a halt. I changed the coding to set the car`s speed to 2 whenever it touched the light green grass. I kept the original code for the grass in the darker green grass, so that if the player actually went WAY off course, they would be punished.