Car data tables from the EPA
 

You can download car data tables that are (in part) used to help determine the road loads for the EPA fuel economy test cycles. I didn't know that...

Test Car List Data Files | Cars and Light Trucks | US EPA

The header for the 2016 table is below. NOTE: I believe that the "Cd" in most or all of the entries below means "Code". There is a Road Load (derived) figure, which I put in red. It is unclear what most of the coefficients near the end of the list are, but I bet some of them have to do with rolling resistance and aero drag.

Model Year,
Vehicle Manufacturer Name,
Veh Mfr Code,
Represented Test Veh Make,
Represented Test Veh Model,
Test Vehicle ID,
Test Veh Configuration #,
Test Veh Displacement (L),
Actual Tested Testgroup,
Vehicle Type,
Rated Horsepower,
# of Cylinders and Rotors,
Engine Code,
Tested Transmission Type Code,
Tested Transmission Type,
# of Gears,
Transmission Lockup?,
Drive System Code,
Drive System Description,
Transmission Overdrive Code,
Transmission Overdrive Desc,
Equivalent Test Weight (lbs.),
Axle Ratio,
N/V Ratio,
Shift Indicator Light Use Cd,
Shift Indicator Light Use Desc,
Test Number,
Test Originator,
Analytically Derived FE?,
ADFE Test Number,
ADFE Total Road Load HP,
ADFE Equiv. Test Weight (lbs.),
ADFE N/V Ratio,
Test Procedure Cd,
Test Procedure Description,
Test Fuel Type Cd,
Test Fuel Type Description,
Test Category,
THC (g/mi),
CO (g/mi),
CO2 (g/mi),
NOx (g/mi),
PM (g/mi),
CH4 (g/mi),
N2O (g/mi),
RND_ADJ_FE,
FE_UNIT,
FE Bag 1,
FE Bag 2,
FE Bag 3,
FE Bag 4,
Target Coef A (lbf),
Target Coef B (lbf/mph),
Target Coef C (lbf/mph**2),
Set Coef A (lbf),
Set Coef B (lbf/mph),
Set Coef C (lbf/mph**2),
Aftertreatment Device Cd,
Aftertreatment Device Desc,
Police - Emergency Vehicle?,
Averaging Group ID,
Averaging Weighting Factor,
Averaging Method Cd,
Averging Method Desc

The Target Coef and Set Coef A/B/C numbers are the test "...electrical dynamometer...coefficients..." that EPA uses to mathematically estimate road-load power (at V = 50 mph):

HP(RL) = (A + V·B + V^2·C)/7.5

HP(RL) = (A + 50·B + 2500·C)/7.5