Speed Test Pack (1 track)
This DLC adds the 'Speed Test' feature to Gran Turismo 5.
The testing includes acceleration and top speed tests, making it possible to measure the acceleration time, section time, top speed, and a variety of stats on your cars.
The DLC also includes the 'Special Stage Route X Oval' track, a course designed as a stage for speed tests. This 'Special Stage Route X Oval' track can also be used in Arcade Mode and Online.
Price: $3.99
Speed Test
Speed tests are only available to players who have purchased and installed the relevant downloadable content. When the content is installed, the Speed Test icon will appear on the GT Life screen. In a speed test, acceleration time, sector time, maximum speed and maximum G-force can be measured.
Selecting the Speed Test icon on the GT Life screen will take you to the Speed Test main menu. From this screen, you have two options: "Begin Measuring Acceleration Capabilities" and "Begin Measuring Top Speed". Selecting "Begin Measuring Acceleration Capabilities" will allow you to record your acceleration time, sector time, and maximum G-force, while selecting "Begin Measuring Top Speed" will allow you to record your car's fastest speed.
Your best results for each of the measurement criteria are displayed on the right-hand side of the Speed Test screen. Selecting a result will bring up the rankings for that particular measurement.
Special Stage Route X Oval
Length: 18.82 miles Longest Straightaway: 7.46 miles Elevation Change: 213.3 ft Corners: 2 
A massive oval track where you can even test the top speed of the X2011
This is a massive oval track placed in a wide landscape with mountains in the background. The track is truly out of the ordinary; the straightaways are 12 km in length, with a total length of 30 km (approx).
It can be used to test any racing car, and even cars like the Red Bull X2011 with its seemingly limitless level of performance.
The surface is fully flat, and because the curves are large in radius they can be driven at full throttle. The only thing you have to watch for is the start/goal section which is a narrow square tunnel.
Course Map
Source: http://us.gran-turismo.com/us/products/gt5/dlc/speedtest/
