To enter Road Rage (the way you get a bajillion points), you drive over boost panels and bonk cars (police do not count.), both of which increase the meter by one point. When you reach 100+ points, the next stage you enter will trigger road rage. Any less than 100 and nothing will happen. Crashing decreases your points by 20.

A friend and I have made a simple mod that adds a display meter for Road Rage, which you can find on the (currently empty) gamebanana page for the game:
https://gamebanana.com/mods/473584
You can turn on an X/100 road rage counter at the bottom of your screen if you turn on FPS visualizer in the settings of the game. Turning on detailed will display an X/8000 counter, which is your score threshold for the next rival car to spawn.

To install the mod, Unzip the download and choose the file you want (read the instructions.txt for more details) rename the file to "data.win" and copy it. In Steam, go to the game in your library and then go to Manage > Browse Local Files. Replace the data.win file in the game folder with the new one. Then youre done! you can launch the game and smash as many pedestrians as you want!