Liberty City (HD Universe)/Geography

. The geography of the Grand Theft Auto IV and Grand Theft Auto: Chinatown Wars renditions of Liberty City can be distinguished by its location on the east-coast of the United States of America, situated in the harbor where the West River and Humboldt River run into the land, dividing Liberty City from Alderney, and separating Liberty City into three distinctive islands; Algonquin, Bohan and "The East" - consisting of Dukes and Queens.

Districts
Each of Liberty City's 56 districts is identified both on the physical copy of the GTA IV map and on the in-game HUD and map.

Grand Theft Auto IV
The majority of traffic lights in GTA IV are based on McCain traffic signals, the iconic yellow-style traffic lights in New York City.

Traffic lights operate as intended and in accordance with the United States signalling and operation standards. When signaled red, traffic will stop, when signaled green, traffic is allowed to move, and when amber, traffic prepares to stop. Traffic lights do not flash amber in any occurrence in-game.

Most traffic signals can be destroyed, in a similar way to street lights. The main light pole itself can often be broken away from its road mounting, disabling the traffic light and producing sparks. The light will then fall and as a result, each section will break apart. AI traffic will behave as if the traffic light is still functioning and operate as normal. Traffic signals hung from a boom are able to swing. They can be seen swinging back and forth in any weather condition, but much faster and aggressively in wind and rainy conditions.

All traffic lights systems operate at the same speed and do not consider traffic flow or congestion. A red light will take 10 seconds to change to green, and 12 seconds (including orange) to change back to red.

Various traffic light poles also have pedestrian signals attached. These iconic devices are built-in yellow boxes attached to the main pole just above human reach. On the box is a black display featuring a hand and a walking human. The hand will light up red when pedestrians are advised not to cross due to crossing traffic, and the walking human will display white when it is safe to cross.

The typical intersection layout varies by location, Algonquin being vastly different from the rest of the city. Small intersections around Broker, Dukes and Bohan usually consist of a single traffic light with the respective number of traffic signals on it, while Algonquin's grid system and repetitive string of one-way streets results in the majority of intersections consisting of three traffic lights; two single poles for two-way flowing traffic on the avenue, and a large dual-lane pole for the one-way flowing street.

As already noted, traffic behaves as expected with traffic lights, however the advanced level of AI pathing can often cause a variety of notable repercussions often caused or dependent on timing between the signal change and flowing traffic. Fast flowing AI traffic approaching a green-turning-red traffic signal will usually halt at the last minute, but depending on the speed the AI vehicle was travelling, a vehicle which stops after the stop-line often proceeds with their journey having stopped, ignoring the red light. The same occurs in the reverse situation, fast flowing AI traffic approaching a red-turning-green traffic signal will halt and continue. Traffic usually does not become inpatient with long-lasting traffic jams caused by traffic lights and vehicles will not normally jump red lights.
 * AI behavior

Taxi drivers who are told to "hurry up" by the player will jump red lights, avoiding traffic by simply driving on the other side of the road through the intersection. Distressed pedestrians will also ignore red lights, for example, if they recover a stolen vehicle from the player, or are disturbed by surrounding explosions or gunfire (unless they leave their vehicle). Responding emergency vehicles will ignore traffic lights, however their responding AI, particularly of Ambulances also often causes collisions with other vehicles, pedestrians and road-side props.

Pedestrians will also behave correctly with pedestrian signals. Approaching the crosswalk, they will only cross when the signal displays the white figure, unless distressed, or physically pushed into the road. The white figure displays when the opposing traffic flow does not intersect with the crosswalk, however, due to a minor oversight with signal behavior and limitations, the lack of a turning filter often causes traffic to almost or completely run down pedestrians when turning; this is most notable at box intersections when crossing pedestrians are safe to cross, but turning traffic makes it unsafe. Pedestrians will react to the situation, both parties often insulting each other, before carrying on with their day. This oversight is present on almost every single intersection in Liberty City.

Pedestrians will also hurry quickly when the light begins to flash (indicating that traffic will begin to start). This light flashes at the last 2 seconds of the 12 second window they have to cross.

There are 11 different traffic light models in-game.

Traffic Lights

Pedestrian Lights