BMTC bus route numbers are assigned as follows:
A major route between two important places will be assigned a number (Majestic to BTM is 25, Majestic to Kadugodi is 335). Generally two digit numbers are for city services (old city limits) and three digit numbers till 499 are suburban services. 500+ are ring road services.
Any bus which travels 60% or more on the “parent” route is given an alphabet suffix. This would include buses which start from one of the points (usually the starting point of the spoke, the hub, and not the destination) and shares the route for atleast 60% of its length with the “parent” route or runs between the same end points but takes a different route. Volvo bus services will have another suffix of their own.
So, 25E (Majestic – JP Nagar 3rd Phase) shares the route with 25 from Majestic to Jayadeva circle where it diverts onto Bannerghatta Road. 335E is the Volvo service from Majestic to Kadugodi while 335T from Majestic terminates at ITPL, short of Kadugodi. 314 series all run from Majestic to various places in and around CV Raman Nagar area and so on. 330 is from Shivajinagar to Marathahalli while 333 is from Majestic to Marathahalli.
G series (Big 10) are buses which connect the CBD (Central Business District) MG Road and thereabouts with far flung suburbs of the city like Hoskote, E-City, Kadugodi, BNP etc. They are numbered like a circle or spokes on a wheel.
© Vinod Vadakkadath