Road Tax on Re-registration in Haryana is based on Depreciated valued of the car as assessed by RTO Officer based on Invoice and Insurance IDV Value of the car. An estimated depreciated value would be calculated and on this amount road tax need to be paid
If the valuation amount, as asessed by officer is less than 6 Lakh - then 5% + approx Rs 1000 will be charged, else if valuation amount is more than 6 Lakh then 8% of the value would be charged
For documents - you may refer article on -Re Registration
Hope should help !!