SLGI Taxis

The SLGI taxis are roaming automated vehicles. Technically, they are at the limit between automated and roaming vehicles. They have pre-programmed routes and the ability to chose route at each main junction they encounter. Unlike the SLGI Trains and SLGI Fleet, they do not have a schedule, as it is impossible to predict which way they should go.

## History

The project was suggested to SLGI team by two residents back in 2016 after the collapse of Second Life Transport Authority, at that time, the largest transport company by logistics and second largest by land coverage after the Yava Script Pods. Due to complexity of such a project, it was never done.

The project was again suggested in 2019 and 2020, but again, it never got through because of the immense challenges it would take. It finally got in experimental state in March 2023.

## Principles

It is said that *a drunk man will find his way home but a drunk bird might get lost forever (Shizuo Kakutani)* [1] [2]. This is a classical problem for mathematicians in random walks. The theory says that a drunk man (aka a point) that moves at random through a 2D space will have a 100% chance to arrive back to the point where it started, having infinite attempts to reach it. On the other hand, a drunk bird randomly moving through a 3D space will have a less than 100% chance to arrive (more exactly 34%). Starting from this, one might ask what is the chance of a mouse to make it through a maze? In theory, it is 100% (if it keeps on trying) and within a finite number of attempts. The same can apply for a vehicle that is making random choices at each junction and chose to travel along roads, railways or waterways.

SLGI taxis travel with a chosen speed along their way and give insights about the features they encounter. However, unlike any other vehicle, they are unpredictable and at every junction they might turn one way or another. They are designed not to turn back except for dead-ends.

The main reason while these vehicles are being built is that they can achieve something that most automated vehicles don't: the element of surprise, the fact that you can embark on a trip to the unknown, to discover places that maybe you don't know or have forgotten about.

## Technology

While automated vehicles follow a series of navpoints along a specified route, roaming vehicles try on their own to guess which way to go, scanning the land and calculating which way is the best through.

Roaming automated vehicles do something else: they have all routes pre-programmed. The route map is divided into hundreds of sections, joining each one at junctions. The taxi follows instructions while along a section. Then, at the next junction, it has the option to chose between a number of sections. There might be from 1 up to 10 options at each junction. This is a completely different concept and needed a big change to SLGI Technology.

## Vehicle Frequency

The SLGI Trains and SLGI Fleet are released following a schedule that ensures a vehicle goes along one way each 6 hours. Vehicles can be more frequent when they have to follow a common route (for example on the main line of Second Life Railroad or along the common flying route through East Nautilus). SLGI taxis are intended to be released in such a manner that they would visit the same piece of land every 6 hours. They are released from **SLGI West Base** (*House Of Freedom - Achemon*) every 6 hours and monitored. Their release time is:

* SLGI Taxi Heterocera: 0.02, 6.02, 12.03, 18.92
* SLGI Taxi Sansara: 0.03, 6.03, 12.03, 18.03

Tests have shown that the taxis roam usually for slightly more than 6 hours. Sometimes they can return home in less than an hour, sometimes they can roam for days until a sim restart process destroys them. On average, they might travel on the same route once every 20 hours, but this is not a rule. Sometimes they might return within a few minutes or not pass through the same route for days. They tend to be attracted by certain areas (as some places have a higher road or waterway density).

## Land Coverage

The only continents that are suitable for these vehicles are Heterocera and Sansara. The other continents don't offer such a complex network of roads and waterways.

Taxis are instructed to fly at 4 m above roads to allow drivers go through. They move closer to surface if there are low bridges or a station is needed. Also, on busy waterways, they fly at 10 m or even higher above water to allow boats to pass through. In places where boats are very rare or where a station is needed, taxis might move on water surface or even beneath surface if there is something interesting to see.

## Design

At the moment, the taxis use only one design: that of a green chair. Other, improved designs, might become available in the future.

## SLGI Taxi Heterocera

This vehicle is released in House Of Freedom, Achemon, four times a day, at 0.02, 6.02, 12.02 and 18.02. It visits all roads except route 6 and The Great Wall and it does not go through the railways unless rails are placed on road surface. This is because SLGI Trains cover the railways and route 6. They also move along almost all waterways. A few small and short water channels as well as waterways that don't allow objects to entry are not served.

* Junctions: 82
* Sectors: 291
* Total distance of sectors: 2096 km.

If by random chance the vehicle returns to House Of Freedom, it has the option to continue roaming or self-destruct.

## SLGI Taxi Sansara

This vehicle is also released at House Of Freedom, Achemon - Heterocera four times a day, at 0.03, 6.03, 12.03 and 18.03. It visits all roads and waterways that have object-entry enabled. It does not enter railways (which are sreved by SLGI Trains) and try to avoid waterways and roads where SLGI trains pass at low elevation. Service is limited in Bay City only on a few waterways because Bay City has its own transport service. Once deployed in Achemon, it travels over the ANWR Channel to reach the West Volcano Subcontinent, where it starts roaming from the bridge linking Papa and Aluluei sims. If the taxi returns by chance to the bridge, it has an option to return to base in Achemon or continue roaming.

* Junctions: 135
* Sectors: 518
* Total distance of sectors: 3194 km.

## Other Continents

Taxis are not released on other continents than Heterocera and Sansara for 3 reasons:

1. SLGI Fleet has a good land coverage and the ships visit basically any road or waterway that is opened. There are also the Yava Script Pods which explore the land too.
2. Some places like Premium Continents, Bellisseria or part of Zindra don't allow obects entry and so they cannot be served by automated transportation.
3. These continents have simplistic networks of roads and waterways, which limit the choice factor. The other continents have less than 30 junctions and less than 100 sectors. Without enough choices, vehicles would behave strange, travelling too many times on the same route.

## Challenges

All SLGI vehicles are scripted so that they can be destroyed on demand by releasing trackers. Trackers are the fastest moving objects on the grid and they can be equipped to follow vehicles and report their positions. Trackers can, if needed, be sent with a deleter script, removing all vehicles on a route. However, because taxis are roaming, it is impossible to order their destruction because their position is unpredictable.

Another major challenge is that their route is less tested. When a SLGI train or ship is first released into traffic, it undergoes testing, to check if the route is safe. After these preliminary tests, vehicles are released again to establish the best schedule. After the schedule is and published on SLGI Vehicle Schedule, the vehicles are considered safe for passengers. Taxis, however, are roaming and cannot be checked with the same precision. They are released in traffic and monitored, set at first with scripts that report any anomaly detected. However, they require far more time for monitoring to be considered safe because of their random routes.

## See Also

* Second Life Geography
* Automated Transportation
* SLGI Transportation Systems
* SLGI Trains
* SLGI Fleet
* SLGI Transport Policy