One of the big things for me in regards to on road is the car shifts gears. When your car gets on the the straight, shifts, and blurs the back ground for the rest of the straightaway, then you will know one of the big attractions of on road. Also, and this is not necessarily true everywhere, for the same entry fee, you usually get more race time at on road than off road. Most off road A mains are usually 15- 20 minutes while on road is usuually 30- 45 minutes.