ArriveLah - Singapore Bus Arrivals

Natural language bus lookup for Singapore.

Trigger Format

bus from <source location> to <destination location>

Examples:

• "bus from Silat Road Sikh Temple to Queens condo"
• "bus from Tanjong Pagar MRT to VivoCity"
• "bus from my office to home"

Step-by-Step Workflow

Step 1: Geocode source location

Use web_fetch to resolve the source location to coordinates via OneMap API:

https://www.onemap.gov.sg/api/common/elastic/search?searchVal=<source>&returnGeom=Y&getAddrDetails=Y&pageNum=1

Extract

LATITUDE

and

LONGITUDE

from the first result.

Step 2: Find nearest bus stops to source

Fetch the full Singapore bus stop list and find stops closest to source coordinates:

https://busrouter.sg/data/2/bus-stops.json

This returns a JSON object where each key is a bus stop code, with fields:

description

,

road

,

lat

,

lng

.

Compute distance using:

sqrt((lat2-lat1)^2 + (lng2-lng1)^2)

(approximate is fine for short distances). Pick the 3 nearest stops within ~300m.

Step 3: Geocode destination location

Same as Step 1 for the destination. Extract its coordinates.

Step 4: Find which buses go from source stops toward destination

For each of the 3 nearest source stops, fetch arrivals:

https://arrivelah2.busrouter.sg/?id=<stop_code>

Then for each bus service at those stops, check if it passes near the destination using:

https://busrouter.sg/data/2/routes.json

This maps bus service numbers to arrays of stop codes in order. Cross-reference with bus-stops.json to get coordinates of each stop on the route, and check if any stop is within ~400m of the destination coordinates.

Keep only buses that:

1. Have the source stop before the destination stop in their route (correct direction)
2. Pass within ~400m of the destination

Step 5: Fetch live arrival times

For each matching bus at the source stop, get from the arrivelah2 response:

• next.duration_ms

  → minutes until next bus

• subsequent.duration_ms

  → minutes until bus after that

• next.load

  → seat availability:

  SEA

  = Seats Available,

  SDA

  = Standing Available,

  LSD

  = Limited Standing

• next.feature

  →

  WAB

  = Wheelchair accessible

• next.type

  →

  DD

  = Double decker,

  SD

  = Single deck,

  BD

  = Bendy

Step 6: Format and return

🚌 Buses from [Source Stop Name] → [Destination]

Bus [XX]
  ⏰ Next: X min | Then: Y min
  💺 [Seats Available / Standing / Limited Standing]
  🚌 [Double Decker / Single Deck]

Bus [YY]
  ⏰ Next: X min | Then: Y min
  💺 [Seats Available / Standing / Limited Standing]

📍 Stop: [Stop Description], [Road Name] (Stop code: XXXXX)

If no direct bus found, say so and suggest nearest MRT or alternative.

Load Code Reference

• SEA

  = Seats Available 🟢

• SDA

  = Standing Available 🟡

• LSD

  = Limited Standing 🔴

Bus Type Reference

• DD

  = Double Decker

• SD

  = Single Deck

• BD

  = Bendy Bus

• WAB

  = Wheelchair Accessible Bus

API Endpoints (no auth needed)

• OneMap geocode:

  https://www.onemap.gov.sg/api/common/elastic/search

• Bus stops:

  https://busrouter.sg/data/2/bus-stops.json

• Routes:

  https://busrouter.sg/data/2/routes.json

• Live arrivals:

  https://arrivelah2.busrouter.sg/?id=<stop_code>