1. Free body diagram Fundamental relations Power required for road loads

2. Recall vehicle FBD DA x Wsinθ ha Wcosθ W/g ax W h B Rxf z Fxf Rhx A θWf
Fxf
Rxf Wr
Fxr
Rxr x z ha DA
W/g ax
Wcosθ
Wsinθ W hh
Rhx
Rhz h L dh b A B

3. Road Loads - drag

4. Road Loads - rolling Rolling Resistance as a constant
Vehicle Type
Concrete
Medium hard
Sand
Cars
0.015
0.08
0.30
Trucks
0.012
0.06
0.25
Tractors
0.020
0.04
0.20
Rolling Resistance as Function of Velocity

5. Road Loads - grade
grade
Remember: convert grade to angle

6. Spreadsheet on website:
Total Road Loads, Power
Spreadsheet on website: