Believe it or not, there are more dead raccoons because they are getting smarter at living around humans. That allows them to have higher population levels. Rural areas are becoming wastelands (no more fencerows, drained and cleared wetlands, etc. The food is where the cars are, but there are more cars, quieter cars, faster cars, and more waste to eat. People aren't out hunting them as much, either. We also suppress rabies better with monitoring programs, pet vaccines, and research.