ARTIFICIAL CITY

A TRAFFIC SIMULATION

INSPIRATION

http://www.centgraf.net/metroviz/r_external.html

SimCity 4

CitiesXL

http://forum.citiesxl.com/viewtopic.php?f=58&t=3298

INSPIRATION

http://abdussamad.com/archives/60-Classic-strategy-gaming-with-Transport-Tycoon.html

Transport Tycoon

GTA IV

http://rockstarhq.multiplayernetwork.net/news/2067/

INDUSTRY CONTEXT

http://sumo.sourceforge.net/

SUMO

Transmodeler

http://www.caliper.com/transmodeler/

BRIEF

To build a traffic simulator

BREAKING DOWN

Vehicles travel on roads

More than one vehicle at a time

Vehicles will need to react to each other

Multiple road elements

Need mechanism to guide vehicles between them

You travel to a location

Need mechanism to guide to goal

REQUIREMENTS

A road network to navigate in relation to

Multiple vehicles with separate destinations that can react to each

other

A means for vehicles to move locate and reach their destination

DESIGN DECISIONS

2D vs. 3D

Language?

Complexity

Grid vs. Free-form

Metadata?

Network generation?

DESIGN DECISIONS

2D vs. 3D

Language?

Complexity

Grid vs. Free-form

Metadata?

Network generation?

2D

Free-form

C#

Fixed vehicle attributes

Pre-coded Scenarios

Not beyond performance

FREE-FORM ROADS

Join the Dots

Time expensive to design large networks this waySystem can speed process by calculating roads itself

ROAD “STRIP”

Smallest linear component of a road that may be curvedPlace together to represent curves

Two coordinates held in association

Use offset values to render as a stretch of

tarmac

MULTIPLE DIRECTION ROADS

Issues with interpolating the nodes

Made worse by sharp corners and multiple lanes

Issues with smoothing

SHARP CORNERS

Road width increasing at corners

SMOOTHING CORNERS

Unequal number of lane elementsLoss of relation to node

VEHICLE CONCEPTS

Components govern performance

Occupant governs behaviours

PERFORMANCE

Acceleration/Speed depend on power and

weight

Cornering depends on brakes and chassis

BEHAVIOURS

Stopping Distance

Comfortable top speed

Severity of Acceleration/Deceleration

Depends on Driver Sometimes feelings,

such as stress or impatience

Other times as preference or habit

Lane changing behaviours

BASIC MOVEMENT

Move towards target nodeFor example, one from a road “strip”.

Don’t collide with other vehiclesTry to match pace

MORE COMPLEX INTERACTIONS

Attempt to bypass obstructions

Beware of new vehicles which might present collision risks

FUZZY LOGICMulti-value approach to logic

Decimal based membership of values

Represent Driver as collection of fuzzy sets

Supply situational information and de-fuzzify key values to determine decisions

LANE CHANGE EXAMPLE Driver waits at the back of queue for lights to change

The driver method processes that the adjacent lane has a cars length of space

Potential Space > Car Length

The adjacent lane has no streaming controls, thus the driver can continue on a direct route to their destination from it

Route suitability is true

The driver has a low membership value to the Impatience fuzzy set, but currently possesses a high membership to the Stress set which has been increasing due to not reaching locations as rapidly as the path-finding algorithm expected them to.

The de-fuzzified value combined with the earlier variables passes the threshold value and the car maneuvers into the free space

PREREQUISITES The more freedom of navigation an automated element is given

the greater the scope for error

This can be managed by properly training the automated elements before declaring the simulation finalised

Movement of vehicles with relation to nodes requires a finalised network structure

ROUTE-PLANNING

The means of determining the shortest route from point A to point B