lta_data_mall is an unofficial client for accessing LTA Data Mall APIs.

Currently, only the Bus Arrival API (Version 2) can be accessed via this gem. Other APIs will be progressively added.

• Homepage: https://www.yusry.name/gems/lta_data_mall
• Git Repository: https://www.github.com/yusryh/lta_data_mall

Add this line to your application's Gemfile:

gem 'lta_data_mall' git: 'https://www.github.com/yusryh/lta_data_mall'

This gem does not rely on any additional gems or libraries other than StdLib.

And then execute:

$ bundle

Prior to usage, please ensure that you have obtained a API Account Key. You can obtain one from https://www.mytransport.sg/content/mytransport/home/dataMall.html.

First, create an initialiser. If you are using Rails, you can create /config/initializers/lta_data_mall.rb and add your account key.

LtaDataMall.configuration do |config|
  config.account_key = 'My Account Key'
end

To get bus arrival information, instantiate a copy of the LtaDataMall::BusArrival class and call the .get_bus_arrival method and supply the bus stop code as a String and an optional bus route as a String

bus_arrival = LtaDataMall::BusArrival.new
stop_83139 = bus_arrival.get_bus_arrival('83139')

This will return an instance of the LtaDataMall::BusArrival::Stop class. You have the following instance methods in this class.

• .response_datetime - Returns a DataTime object containinng the API server's response timestamp. You can use this to calculate time offsets.
• .stop_code - The bus stop code of this API call request.
• .services - An array of LtaDataMall::BusArrival::Service objects containing bus services and their arrival information.

LtaDataMall::BusArrival::Service has the following instance methods.

• .no - Route number
• .operator - A symbol designating one of the following bus operators.
  • :sbst - SBS Transit
  • :smrt - SMRT Buses
  • :tts - Tower Transit Singapore
  • :gas - Go-Ahead Singapore
• .arrivals - An array of LtaDataMall::BusArrival::Bus objects containing the specific arrival information.

LtaDataMall::BusArrival::Bus has the following instance methods.

• .origin_code - The bus stop code where this bus started its trip from.
• .destination_code - The bus stop code where this bus will end its trip at.
• .estimated_arrival - A DateTime instance indicating the bus' approximate time of arrival.
• .visit_number - The bus' visit count to this particular bus stop on this particular trip.
• .load - A symbol indicating the bus' load.
  • :seats_available - Seats are available
  • :standing_available - Standing space is available
  • :limited_standing - There is limited standing space
• .is_wab? - Indicates if the bus is a Wheel-Chair Accessible bus.
• .vehicle - A symbol indicating the vehicle type.
  • :single_deck - A single-deck rigid bus. For example, a Scania K230UB or a Mercedes Benz Citaro, MAN A22, Volvo B10BLE (non-WAB), or Volvo B10M (non-WAB)
  • :double_deck - A double-deck rigid bus. For axample, a Volvo B9TL, Dennis Enviro 500, MAN A95, Volvo (Super) Olympian (non-WAB), or Dennis Trident III (non-WAB).
  • :articulated - A articulated (or bendy) single-deck bus. For example, a Mercedes Benz O405 (non-WAB), or MAN A24.

In case LTA's documentation is not clear enough, I am giving a few examples to allow you to understand this matter.

Disclaimer: I am a a bus, train, plane, and mobile crane enthusiast. I am explaining this in my personal capacity as an enthusiast.

Bus operators in Singapore generally use coloured plates to indicate bus routes that visit the same bus stop more than once but heading towards different directions. These coloured plates are sometimes also use to indicate dual-circuit bus routes. For example, clock-wise and anti-clockwise routes. Additionally, there are bus routes that have north-south or east-west loops that visit an interchange between loop, that do not use any sort of coloured plates, but visually using a terminating indicator in its route number.

Green-White plates are generally used to indicate bus routes that operate in a clockwise and anti-clockwise direction. These buses are usually given separate bus route numbers, for example, 225G/225W, 243G/243W, and 410G/410W. So these generally do not need special handling.

Red-White plates are usually used to indicate indicate bus routes that visit the same physically bus stop while operating in different directions. For example, route 155 visits the same multiple bus stops in MacPherson estate while heading towards both Bedok and Toa Payoh interchanges. For route 155, use .origin_code and .destination_code to determine the plate colour. Other known services operating in such a manner are routes:

• 21
• 123
• 124
• 125
• 129
• 131
• 136
• 139
• 186

Generally, 'red' indicates direction 1 and 'white' indicates direction 2. LTA's API would return two LtaDataMall::BusArrival::Service entries; one for each direction.

In other cases, you need to utilise .visit_number to determine its plate colour. These routes are generally loop services that visit the same bus stop before and after its looping point. For example, route 60 visits bus stops 84501 and 84511 both before (.visit_number of 1) and after (.visit_number of 2) its looping point. Other known services operating in this manner are routes:

• 73
• 315
• 317

Generally, 'red' indicates heading towards looping point, and 'white' indicates heading from looping point and back to its origin.

Buses operating in this manner are usually due to route amalgamation of 2 or more formerly-looping bus services that operated from the same origin bus stop. They generally operate in the following manner:

• Origin bus stop
• Operate first loop
• Visit the origin bus stop again.
• Operate second loop (if not terminating/ending)
• Back at origin bus stop and repeat.

These buses usually operate continuously. The rationale is to allow travelers to conveniently travel between both loops.

Buses that will not be proceeding to operate the next loop will indicate an E or T (for Ending or Terminating) in their route numbers prior to beginning their current loop. This is not indicated in the API and thus there is no way to find out whether an arriving bus is terminating at the end of the loop or proceeding to the next loop.

Known bus routes that operate in this manner are the following routes:

• 358
• 359
• 911
• 912
• 913

There is another bus route - 307 - that operates in a similar manner, except that it does not return to the Origin bus stop when traveling from the first loop to the second loop; it does that only when traveling from the second to first loop.

For routes 358, and 359, use .visit_number to determine the loop.

For routes 911, 912, and 913, Woodlands Interchange is indicated with a different bus stop code - 46008 instead of 46009 - when commencing its second loop. Thus, bus stop code 46009 would only indicate buses heading towards the first loop, while 46008 indicates bus heading towards the second loop.

Since the handover of route 36 to Go-Ahead Singapore, route 36 has been operated in a fairly confusing manner.

Officially, route 36 begins and ends its trip at Changi Airport Passenger Terminal Building 2 (bus stop code 95129).

Prior to hand-over, the buses operated in a continuous loop, which meant that boarding the bus prior to bus stop 95129, meant that you could continue the trip beyond that bus stop.

Since the hand-over, buses usually do terminate at bus stop 95129 (Terminal 2). However, the buses will actually begin their trip at Terminal 3, proceed to Terminal 1 and then Terminal 2 before officially commencing the trip. As trip commencement officially starts at Terminal 2, there is no indication via the use of .visit_number at Terminals 3, 1, or 2, that indicates whether the bus is beginning or terminating.

Generally speaking, if a particular bus is crowded at Terminal 3 (the first terminal building it visits), it is likely to be a terminating trip. Likewise, if it's empty at Terminal 3, it is likely to be starting a new trip.

Bug reports and pull requests are welcome on GitHub at https://www.github.com/yusryh/lta_data_mall.