This is from Cummins' paper on fuel economy... page 26: https://cumminsengines.com/...ter_fuel_economy.pdf
Road Surface Resistance % (compared to concrete):
Asphalt with finish coat 1%
-medium coarse finish 4%
-coarse aggregate 8%
Chip and Seal Blacktop 33%
So here we have chipseal creating 25% higher rolling resistance for a truck. I expect it to be similar for a car. When traveling at 60mph, rolling resistance is typically ~40% of what a car overcomes on a flat road. So ~10% increase in power requirement or 10% reduction in mpg.
Road Surface Resistance % (compared to concrete):
Asphalt with finish coat 1%
-medium coarse finish 4%
-coarse aggregate 8%
Chip and Seal Blacktop 33%
So here we have chipseal creating 25% higher rolling resistance for a truck. I expect it to be similar for a car. When traveling at 60mph, rolling resistance is typically ~40% of what a car overcomes on a flat road. So ~10% increase in power requirement or 10% reduction in mpg.