Since there is a link between the animation path and the car you can offset the car's position or orientation from the path's. If I understand correctly you want to offset the orientation so that the car is facing the opposite direction. Here is some code that takes 2 wheelbarrows and animates them along a path. The second wheelbarrow will get rotated so it faces the opposite direction. Then its position is offset slighty from the path so it appears below the first one. Let me know if that helps.
Code:
import viz
viz.go()
wheel1 = viz.add('wheelbarrow.ive')
wheel2 = viz.add('wheelbarrow.ive')
path = viz.add(viz.ANIMATION_PATH)
positions = [[0,0,10],[5,0,10],[5,0,15],[0,0,15]]
for x in range(0,len(positions)):
cp = viz.add(viz.CONTROL_POINT)
cp.setPosition(positions[x])
path.add(cp,x+1)
path.constantspeed(viz.ON,1)
path.loop(viz.LOOP)
path.translatemode(viz.BEZIER)
path.setAutoRotate(viz.ON)
#link the first wheelbarrow to the path
wheel1.link(path)
#link the second wheelbarrow to the path then
#offset the wheelbarrow's orientation so it is opposite the path
#and offset its position from the path so it will be
#below the first wheelbarrow
wheel2link = viz.link(path, wheel2)
wheel2link.preEuler([180,0,0])
wheel2link.preTrans([0,-1,0])
path.play()