Here are some more fun things to do in the Carmageddon demo. They're a lot easier to do if you have the crack that disables the timeout (don't ask me for the crack, search the Web, maybe try avault). Read my Loving Carmageddon!!! to get a sense of the game and a lot of fun things to do, and also check out the FAQ at http://www.aiusa.com/noyzrulz/carma/carmfaq.005.
The counter indicates a maximum 377 pedestrians. I've nailed 345 in easy mode. There are three keys to getting all the pedestrians:
Use <Tab> to see where you are on the map, and keep exploring. There are pedestrians on roofs, pedestrians inside the indoor areas around the fourth checkpoint, women in the fountain, pedestrians hiding behind barriers, lots of pedestrians in the badlands at the bottom. Often they hide in doorways. You may find cockpit view (press <C>) useful, as you can aim better for pedestrians, and you can use <Q>, <W>, and <E> to look left-front-right as you look around.
Often pedestrians hide in doorways. Easy piledriver bonus, or you can slide it for a combo bonus.
To stop the other cars, get a position near the front, bang into a few cars in front to annoy them, then slam into reverse and kill the cars behind you. It's still very difficult to get everyone else to avoid killing a few at the start. Waste all the other cars besides the dumptruck as quick as you can, then periodically press <Tab> to see if the dumptruck is nearby while you're hunting pedestrians. If he is, you can flip him, or race away.
Kill off the other cars then leave the Dumptruck for last. You can outrun Don Dumpster, and he often winds up on his back. Eventually he reappears after a timeout, but you can race away easily.
Here's one approach to wasting the dumptruck, if you're Otis in the Cadillac. Haven't tried it with other cars.
Here's one in the Splat Pack where I slammed two cars so hard they melded together.