You’ve done a great job with the technical elements of these two photographs. In your first image you’ve shown your ability create a shallow depth of field. In your second image you’ve shown your ability to create the illusion of motion within a 2 dimensional photograph.
Your first image has compositional strength as well. You’ve used a limited color palette consisting of the complimentary colors of red and blue and the photograph is full of texture and has depth not only due to your shallow depth of field, but also your object placement.
This image however doesn’t apply the rule of thirds. It uses a more formal sense of balance and the centered look of the image make it less dramatic that it could be.
As stated above, your second image showcases your ability to show movement, but from a composition standpoint there are some issues that need addressed.
Most noticeably, your exposure is too high. You have areas (especially on the road) that are completely “blown out”. This is a common problem with digital cameras. They have a hard time handling dynamic range. We’ve recently written a blog post on this issue and I think it would be very helpful for you to read it.
http://photographyicon.com/blog/2008/11/26/digital-cameras-latitude-dynamic-range/
Other than those issues, I think you’re off to a great start. Just remember to always give consideration to balance and exposure.