Vehicles in GTA V/Scenarios

Scenarios are partially scripted events involving vehicles, as well as pedestrians and animals in Grand Theft Auto V.

Description
A scenario refers to a partially scripted sequence wherein a vehicle, animal or pedestrian will spawn and complete a request. They differ from regular events as they are specific to certain areas.

Scenarios involving vehicles often rely on a  to complete the request. The model set file contains a list of vehicles in which the scenario will pick, at random, to spawn when playing the sequence. Specific vehicles are listed under specific model sets, for example, the Ambulance model set contains the Ambulance, and the Construction Cars model set contains various construction vehicles.

Spawning
There are various examples of scenarios in the game. Some of these will not occur in GTA Online to increase overall stability and performance.

The path is usually only a few nodes long, allowing the vehicle to make its own decisions after following a short scripted sequence.
 * Drive Solo

These serve a similar purpose to regular parked vehicles but are often specific to a set of specific vehicles (model sets), making them slightly more unique. When empty, these vehicles are unlocked and do not require the player to smash the window or pick the lock to enter, and subsequently won't give the player a wanted level. Many of these are found within car parks among regularly spawning parked cars (the latter of which are locked), while some are parked in special areas such as Fire Stations and Hospitals.
 * Empty


 * Drive Passengers

Travelling
The last node determines what the vehicle does next.
 * Drive

Exiting
The next step usually involves the driver and passengers exiting the vehicle and walking over to a specific location, however this is down to the pedestrian nodes.
 * Park

At this point, the AI can make its own decisions and so its traveled direction is usually random, however it is more-often-than-not influenced by the position the vehicle is left in, for example if the vehicle follows a specific road which has no turn-offs, the vehicle will likely follow the road and doesn't become completely unaware of its surroundings. Planes usually fly in a constant straight line unless distracted.
 * Drive

Scenario Behaviour
In almost all cases, vehicles in a scenario will behave almost completely identical to regular ambient traffic, however there are situations in which scenario vehicles will behave different or "odd" because of the circumstances they are placed under. A notable example is how Ambulances and Fire Trucks behave after spawning in a response situation, driving out of their location and following a relatively long path until merging into regular traffic. These vehicles often drive recklessly as they are told to avoid stopping for other traffic. Other traffic that get in the way will often be rammed out of the way by the vehicle. It can also be noted that these vehicles will sometimes behave unusually when following them, including unusual driving behaviour such as becoming stuck and driving in circles.

At Los Santos International Airport, landing planes will begin to take off again if they are disturbed. This can be done in several ways, such as crashing into the landing plane, or shooting near them. Nearby explosions will often have an immediate effect on them. Parked vehicles spawned by scenario are not locked, meaning the player can access them without smashing a window. This means nearby pedestrians will not react or become hostile to the situation and won't report a vehicle theft. Though few and far between, some parked vehicles that follow this trait are one of the Fire Truck spawn positions at the El Burro Heights Fire Station (only the left of the three doors), or heavily modified vehicles parked outside Los Santos Customs in Burton and at LSIA.

List of Vehicle Scenarios
There are currently 145 vehicle model sets from which vehicle scenarios can occur. These model sets range from different categories vehicles may fall under, such as construction vehicles, aircraft, police vehicles and trucks. Within those 145, there are two GTA Online exclusive model sets which were added as part of the Smuggler's Run update, spawning the white Speedo and green Mesa outside LSIA hangars and Fort Zancudo hangars respectively.

NPC Modified Vehicles
In the enhanced version of the game, heavily modified vehicles appear both driving around and parked in specific locations around the map. These vehicles can be stolen and stored as normal, and have an array of modifications applied, some with unique pearlescent colors unavailable in Los Santos Customs. Many of these vehicles were added in DLCs after the initial release of the game on the Xbox 360 and PlayStation 3.

With the exception of modified Tornadoes, Peyotes and Buccaneers, all of these are only obtainable in the enhanced version of the game.

Trivia

 * An unknown vehicle model set, internally named "FARM_WORKERS" within  files, is referenced numerous times across the map, but does not occur. "FARM WORKERS" does not exist within   and the game simply resorts to spawning a regular Bison. It is likely this is a beta model set which contained the Bison alongside other farm vehicles, suggested by the name of the model set.
 * An unused vehicle model set, "ROCKFORD_CARS" can be found within the  file. This model set contains various sports cars as well the Cheetah, a car that does not appear in regular gameplay, but as the model set appears to be unused, the Cheetah does not spawn in regular traffic scenarios.

Bugs/Glitches

 * In the enhanced version of the game, Jet planes flying high above Los Santos are prone to spawning in incorrect positions, causing them to crash into buildings. This is very common around Rockford Hills and Richman. It can often occur when starting a mission as Michael at Michael's mansion as this gives the game a chance to spawn the scenario.
 * On rare occasions, planes may also collide with each other and explode in mid air, having spawned too close to each other.
 * Occasionally, Stockade trucks driving out of alleyways can spawn without drivers, but because they are scripted to follow a specific path, still drive normally. This is caused when the game fails to request the driver model in time, often a result of driving too fast while the scenario loads.
 * Helicopter behavior sometimes causes pilots to crash during a scenario. While helicopters taking off, such as the Frogger at LSIA or Vespucci Helipad will usually fly much higher than usual when threatened with gunfire or explosions, helicopter that land will insist on landing their helicopter due to the script, but will fly erratically while doing so, usually causing them to crash into surrounding buildings and vehicles.
 * It can be noted that the Benson within the  model set often becomes stuck in several locations that it spawns, due to its length being impractical in narrow alleyways it can often be seen passing through. This is most notable at the position where it spawns pulling out of the FIB Headquarters underground parking lot onto Power Street, as the Benson becomes stuck on the concrete construction barriers just opposite the exit.