Should Buddhists drive a car or a motorcycle? Buddhist first precept is abstain from killing animals. 

Could this also imply that driving a car is unwholesome and not good for a practitioner.



Would not one agree that by choosing to walk is considered kinder as it would have less chance of accidentally killing animals than driving or riding? The same could go that riding is kinder than driving. By taking these kindfull approaches, one would commit less killing and right intention, which would bring better meditation. Please be careful here, I do not imply that driving is wrong, but it can reduce peace in our mind.
Please also see this answer.

When you walk you might accidentally step on ants or other small insects. Does that mean you should stop walking?

From Dhammapada 1:


  On one occasion, blind Thera Cakkhupala came to pay homage to the Buddha at
  the Jetavana monastery. One night, while pacing up and down in
  meditation, the thera accidentally stepped on some insects. In the
  morning, some bhikkhus visiting the thera found the dead insects. They
  thought ill of the thera and reported the matter to the Buddha. The
  Buddha asked them whether they had seen the thera killing the insects.
  When they answered in the negative, the Buddha said, "Just as you had
  not seen him killing, so also he had not seen those living insects.
  Besides, as the thera had already attained arahatship he could have no
  intention of killing and so was quite innocent."
  
  Then the Buddha spoke in verse as follows:      
  
  
    All mental
    phenomena have mind as their forerunner; they have mind as their
    chief; they are mind-made. If one speaks or acts with an evil mind,
    'dukkha' follows him just as the wheel follows the hoofprint of the ox
    that draws the cart.