Step 1 :Find the distance at time t=0: d(0)=0.002(0)^3-0.1(0)^2+3(0)=0
Step 2 :Find the distance at time t=4: d(4)=0.002(4)^3-0.1(4)^2+3(4)=16
Step 3 :Calculate the total distance traveled: 16-0=16
Step 4 :Calculate the average speed: \(\frac{16}{4}\)=\(\boxed{4}\)