Step 1 - Creating the Motion Blur Effect
In Photoshop: Open you're favorite car image. I chose a picture of my 2000 Toyota Celica GTS for this example. To make things easier and keep the photoshop settings in line with this tutorial we will size the image down to 1000 pixels wide. You may also want to boost the saturation a bit to make the car stand out. Duplicate the background layer and name it motion. Now we need to create a selection that we will use a few times in this tutorial. Grab the polygonal lasso tool (feather radius 1 or 0) and select the entire outline of the entire car including wheels. Go to [Select -> Save Selection] and name it car. Now you can de-select the selection. On the motion layer go to [Filter -> Blur -> Motion Blur] with angle 0 and distance of 250 pixels. Create a layer mask on the motion layer and load the car selection [Select -> Load Selection], fill the selection with black to get the car back into the picture. You may want to take a small brush to the mask to catch any details you may have missed. You may also want to paint back some blur where you see reflections in the metal surface Using a low opacity brush. What we have now should look like the bottom image on the right.
Step 2 - Spinning and Smoking
Our fast moving car wouldn't be very realistic with the wheels just standing there would it? It's time to add some Photoshop spin! First we need to copy them into a new image so we can work with them. First, drag the rectangular marquee tool until you have the entire wheel selected. Go to [Edit -> Copy Merged] then create a new image and paste the selection into it. Select [Filter -> Blur -> Radial Blur] with amount set to 50, method set to spin and best quality. Now copy and paste the image back in to the main car image on a new layer on top, you may have to lower the opacity to align the images together. Repeat this technique for the other one and merge them together into a layer. Now add a layer mask and blend the images together. You should now have something similar to this image.
Step 3 - Adding Smoke and Finishing Touches
No speeding car would be complete without smoke particles coming off the tires. Lets get to it! Add a new layer on top, fill it with black and set the layer blending mode to pin light. With black and white as your foreground / background colors, go to Filter -> [Render -> Clouds] until you see some nice puffs of smoke around the wheels. Now add a layer mask and paint out all the excess smoke. With the smoke layer selected use [Filter -> Blur -> Motion Blur] with a distance of about 20 pixels. Finally we want to make the image a little more like a car ad so lets adjust the background a bit. Select the motion layer. Now load in the car selection we saved earlier with inverse checked so we have a nice selection of the background. Add a Photoshop Hue / Saturation adjustment layer and check the colorize box. Move the sliders around until the background complements the car. There you have it, your very own fast car with the help of Adobe Photoshop.