Vehicular combat is an integrate gameplay element in the Grand Theft Auto series that involves combat while the player is on a vehicle. Vehicular combat encompasses anything from the simple act of using a vehicle to damage/disable vehicles or run over pedestrians, to the ability to use a weapon in hand or built into a vehicle.
With vehicle only
The use of a vehicle itself as a weapon has long been a staple in the GTA series, allowing the player to run over pedestrians and collide with vehicles to stop or damage them.
The effects of collisions with pedestrians vary according to speed; vehicles that travel faster are more likely to exert a one-hit kill to pedestrians, and can be more efficient than merely killing using other weapons. However, much like shooting rampages, rampant hit-and-runs will naturally attract the attention of the police.
In Grand Theft Auto 1 and Grand Theft Auto 2, the act of running over pedestrians and colliding with other vehicles awards the player money. Since Grand Theft Auto III, however, monetary rewards are only obtainable by picking up dropped cash that the crash victims drop after being killed. Games between GTA III and Grand Theft Auto: Vice City Stories (except Grand Theft Auto Advance) also impose minor damage penalties to vehicles that run over pedestrians in high speeds.
Games prior to GTA III as well as GTA Advance always depict pedestrians being run under a vehicle; games between GTA III and GTA Vice City Stories however also include animations of pedestrians being tossed over a vehicle. vehicles that run over dead pedestrians will also leave a blood trail marks starting GTA III. In Grand Theft Auto IV, the inclusion of ragdoll physics and Euphoria animation allows pedestrians to respond more naturally to vehicle crashing, being flung or thrown in appropriate speed according to the speed of the player's vehicle. Pedestrians that strike the player's vehicle will also leave blood splatters on the vehicle.
The main blades of the helicopter can be used to instantly kill any people. Until GTA IV, players cannot kill themselves using the blades their own helicopters or police helicopters. Kills using the blades of the helicopter does not warrant the player attention from the police except in Grand Theft Auto: San Andreas. GTA IV introduced additional damage with the blades by being able to collide with vehicles and throwing them around.
On other vehicles
Vehicles may also be used as a weapon with other vehicles, being effective as a battering ram or blockade, and is particularly necessary in earlier games when the player is unable to shoot from a vehicle or does not have a proper viewpoint to do so. Vehicle-to-vehicle battles commonly occur in vehicle chases, which either require that the player merely stop the target vehicle by sufficiently damaging it, or destroy it outright.
Naturally, larger vehicles, while slow, may be particularly useful completely hindering the movement of a smaller vehicle by pinning it against a wall with its weight; likewise, the use of smaller/lighter vehicles, motorcycles, and bicycles are not recommended in chases against larger vehicles. The skill needed to flip a vehicle over or perform a PIT maneuver (as taught at GTA San Andreas' Driving School) is also advantageous.
With built-in weapons
GTA 1 — GTA 2
Weaponized vehicles have in fact appeared since GTA 1, with the introduction of the Tank, followed by the Royal Pain and Tiger Tank in the Grand Theft Auto: London expansion packs. However, the tanks are incapable of firing munitions, and simply have the added advantage of running over smaller vehicles. While non-lethal, the water cannon from a Fire Truck may also be used to incapacitate pedestrians.
GTA 2 marked the first time vehicle-mounted weapons are included in full, with a Tank now capable of firing a limited number of Rocket Launcher-like explosives (outside Kill Frenzies). Likewise, vehicles armed with other weapons are available. The aptly named Armed Land Roamer, which features a roof-mounted machine gun, allows players to fire a stream of bullets forward. In addition to the standard water cannon, the Fire Truck may also be armed with a Flamethrower during a Kill Frenzy. Specialized garages may also allow players to arm standard road vehicles with offensive as well as defensive weaponry, including a pair of Machine Guns, a car bomb, Mines, or Oil Slicks.
GTA III — GTA Vice City Stories
Between GTA III and Vice City Stories, a multitude of armed vehicles were introduced over the course of the game.
The Rhino, a newly designed tank, features a turret that can be rotated by the player in a 360 degree angle, allowing the tank to strike any target around the vehicle while stationary. The Predator, a police boat, is also armed with twin machine guns that shoot forward. Both the Rhino and Predator remain largely unchanged in the following game; in GTA San Andreas, however, the Rhino's aiming system was redesigned to be aimed in the direction the camera is point while on the tank, and has the added capability of moving the turret vertically. GTA Advance features a Tank that bears a similarity to the Rhino, but has the same limited mobility as a Tank in GTA 2.
Following GTA III, weaponized aircraft were also included to varying degrees in each game. GTA Vice City introduced two armed helicopters, the rocket and machine gun-armed Hunter and the machine-gun armed Sea Sparrow, while GTA San Andreas additionally feature two armed airplanes, the missile-armed Hydra and the the machine gun-armed Rustler; the Hyrda in particular is the first vehicle in the series to be armed with target-seeking missiles (whereas other vehicles require the player to manually aim). Due to gameplay limitations, Grand Theft Auto: Liberty City Stories dummies out accessibility to all aircraft, while GTA Vice City Stories' reintroduction of helicopters marked a return of the Hunter and Sea Sparrow, as well as the inclusion of a new machine gun-armed helicopter, the Little Willie.
GTA IV — GTA V
GTA IV is marked with a significant reducation of weaponized vehicles. Due to the increased versatility of shooting a firearm in hand from a vehicle, as well as the ability for passengers of any vehicle to fire a gun (i.e. on a helicopter or the back of a van), no tanks are available in GTA IV, while the Predator is no longer armed with built-in machine guns as passengers on the boat can fire at the player using rifles.
The only weaponized vehicle in GTA IV is the Annihilator helicopter, which is armed with a two pairs of miniguns that can fire large quantities of high caliber, one-hit-kill bullets. Under normal circumstances, the helicopter remains unchanged in both GTA IV as well as its episodes, The Lost and Damned and The Ballad of Gay Tony; in multiplayer modes and selected missions in TLAD, however, Annihilators in TLAD are armed with explosive rounds that can easily destroy vehicles.
With The Ballad of Gay Tony's return to over-the-top gameplay, two more weaponized vehicles were introduced. The APC, which is a heavily armored vehicle with a roof-mounted cannon, is armed with explosive rounds, while the Buzzard helicopter is equipped with a pair of miniguns as well as rocket pods, making the Buzzard more effective as an attack helicopter than the Annihilator.
Grand Theft Auto: Chinatown Wars sees the return of the Rhino tank, significantly redesigned but still armed with a turret, as well as various new attack boats: The machine-gun armed Coast Guard Launch, which serves as a replacement for the Predator, and the Destroyer, a torpedo boat.
With weapon in hand
GTA III — GTA Vice City Stories
Prior to GTA IV, players must have any sub-machine gun in hand in order to perform drive by shooting. While in a vehicle, the player may look left or right to view the target and take aim, then fire their weapon, discharging bullets to the target.
The aforementioned concept has remained the same between GTA III and Vice City Stories, but underwent several changes. From GTA Vice City onwards, players are also allowed to shoot forward while on a motorbike or bicycle, which is usually far more effective than conventional drive-by shooting in cars due to the player being able to watch the road and shoot at a target at the same time; "drive-by" shooting on boats are made possible. Additionally, in GTA Vice City Stories, the protagonist is able to shoot forward while driving the jetski. GTA Vice City, San Andreas, Liberty City Stories, and Vice City Stories allow for non-player passengers of a car to perform drive-by shootings, shooting with pistols or sub-machine guns; however, the effectiveness of this feature is dependent on how close the car is to targets.
The ability for the player to shoot as a passenger was first explored in GTA Vice City, during the missions Phnom Penh '86 (positioned on the side of a Maverick) and Supply & Demand"(positioned on the back of a Squalo), when the player is able to free-aim, but use only weapons with first-person view (the M60 and Ruger). In GTA San Andreas, free-aiming third person view is additionally utilized while the player is seated as a passenger in a motorbike and a car, during Just Business and End of the Line, respectively. A few missions reused the method of first-person free-aim drive-by during Reuniting the Families and The Da Nang Thang (with an AK-47 and Minigun, respectively).
GTA Vice City marked the first time players can perform drive-bys from a helicopter, although this was only avaliable during the mission Phnom Penh '86. However, from GTA IV onwards, players could perform passenger drive-bys from a helicopter.
GTA IV - GTA V
As Grand Theft Auto IV was developed, drive-by shooting mechanics were retooled to allow for more flexible aiming and improved accuracy. The player may aim their weapon freely while driving; the "look left" and "look right" commands were removed in favor of an analog stick-based/mouse-based camera, allowing the player to shoot forward or even backwards in any vehicle; however, shooting backwards is not adviseable. Also, drive-bys were extended to being possible out of helicopters with assault rifles, and as passengers using assault rifles, a first in the GTA series. The player can now use assault rifles to perform passenger drive-bys in any vehicle.
While the choices of weapons for use in drive-by shooting is still limited, the player can now either use a sub-machine gun or pistol, and Grenades, Molotov Cocktails, Pipe Bombs, and Sticky Bombs can actually be dropped from vehicles, useful for blowing up pursuers. The Lost and Damned also introduced the ability to fire a sawn-off shotgun while riding motorcycles. However, even with the ability to use a sawed-off shotgun, drive-bys on motorcycles is highly discouraged, as the player is fully exposed and vulnerable to gunfire, as well as being vulnerable to an Involuntary Ejection.
Overall, the Micro Uzi in GTA IV and TLAD is the best weapon for drive-bys in cars with its incredible rate of fire, while the the Gold SMG in The Ballad of Gay Tony is the best weapon available. The M4 carbine is most suited for passengers on aircraft and boats, but the accuracy of gunfire from a helicopter or on a boat is often abysmal due to difficulty in aiming (due to rapid movement of the vehicle) and a limited field of view.
In GTA V, the drive-by mechanic is mostly carried over from GTA IV; however, if the player does not have a weapon equipped, then the player can "flip the bird" to other drivers or pedestrians. The Micro SMG and the AP Pistol with the extended magazine equipped are the best firearms for drive-bys, while Sticky Bombs are the best weapon if the player needs to use explosives.