According to a report, only 6.27% of cars running in Delhi will be put to the 15-day trial of odd-even formula, beginning January 1. After all the 25 exemptions, only 5.3 lakh cars can be kept off roads on a single day, the report added. Further, 73.9 lakh vehicles, including 55.7 lakh two-wheelers, will be free to ply on roads.