This article covers how vehicles should be tested in the HD Universe of the Grand Theft Auto series to gain "observed" specifications.


While files in Grand Theft Auto IV and Grand Theft Auto V indicate all the performance and handling data for vehicles in the respective games, what is tested in-game can differ from what is defined in these files. Handling.dat (.cfg in earlier games) defines essential qualities of vehicles such as the weight, top speed, transmission, clutch speed and buoyancy. On the GTA Wiki, we display these details on every vehicle article under a designated file-based secton of the performance overview table. This indicates that the speed, weight or gear-number listed in the performance overview table has come directly from the handling.dat files.

While it is believed these files define what the vehicle performs like in-game, these details are only raw, meaning other factors, such as the weight, clutch rate and traction, can all affect the actuality. Because of these factors, we display two details; handling.dat (as mentioned), and "Observed".

Both the GTA IV Overview tables and GTA V Overview tables have a "Defined" and "Observed" section. "Defined" indicates what is written down (or stated otherwise) in-game, such as the handling.dat files or a website claim (the lafter of which can often mis-match both file data and actual speed. "Observed" indicates that a test has been run in-game to get the information.

How we gain "Observed" details

Grand Theft Auto IV

For Grand Theft Auto IV, numerous modifications can be used to display the speed that a vehicle is traveling at. We use the most basic trainer-based modification to get the true results. These speeds come directly from the handling.dat files, and they also take into consideration the aforementioned factors (such as weight and traction) and output the actual speed. In the games, the Handling.dat and "Observed" speeds are usually very similar, or even identical due to the nature of the physics in-game, however, some lee-way can be seen in numerous examples.

Vehicles are tested by using the longest straight, flat road possible. It is most effective to use Columbus Avenue for its notoriously long stretch of blocks. When we test vehicle acceleration, top speed and gears, it is essential we disable traffic. If possible, using mods to "build" a long road out to see can also be done, as long as the surface is completely flat and does not have higher resistance than normal.

Depending on the vehicle, the top speed usually fluctuates a couple of mph, so for this, 3 tests are run, the same distances, then the 3 results are added up, and divided by 3 to gain a mean speed. We round to 1 decimal place for accuracy.

For acceleration, it is best to test up to 5 times, and again, work out the mean speed. A stop-watch can be used to time the acceleration rate.

Gears can be counted without any use of modifications; the number of shifts heard (+1 for the 1st gear the vehicle is in when stationary) is the number of gears the vehicle has. When the engine begins to struggle to rev any higher, that indicates there are no more gears left to shift to.

Grand Theft Auto V

With the PC version of GTA V, we can use an identical method of speed testing, using trainer-based modifications to reveal speed.

We can use stunt tracks for the test ground, as these are the flattest possible surfaces that give us an extremely accurate, stable speed value. There is, on almost every vehicle, a 'steady' top speed at which the vehicle will stay at for almost 20 seconds, and a slightly higher 'top' top speed which will randomly be counted up to after around 20 seconds.

What is the difference?

What is the difference between Handling.dat and Observed?

As already stated, Handling.dat lists raw-speeds for vehicles, meaning what is seen in-game does not necessarily match what is defined in these files. The difference between the two speeds increases as the performance of the car is increased. For example, the Adder in Grand Theft Auto V is stated to have a top speed of 99 mph (160 km/h) in the Handling.dat files, however, the in-game First Person Speedometer top speed is 140 mph (225 km/h), showing a large difference of 41 mph.


The following notes are important to be read.

  • "Observed"/"Tested" = tested (with Speedometer modifications)
  • "Defined" = anything defined in-game. Websites and Handling.dat files are listed here.
  • "(Handling.dat)" = Handling.dat data.
  • Handling.dat speeds are raw
  • Handling.dat speeds are listed in kilometers per hour, so the format listed in the Overview table of Performance sections will require a km/h to mph converter to write it in the correct format on the GTA Wiki.
  • On all Overview tables in Performance sections, the mph number is first, followed by the km/h number. E.g. 140 mph would be written as "140 / 225" (140 mph in km/h is 225). The section lists the metric/imperial systems used and therefore "mph" or "km/h" do not need to be written after the numbers in this format.


Contact any Member of Staff who will either help or pass you on to another member of staff who can answer your question. Alternatively, post a question on the Talk Page of this article.

Last updated by Monkeypolice188 on 18th September, 2017.