The O-Train is a light-rail rapid transit service running from Greenboro Station in the south end of Ottawa, north through Carleton University campus, to Bayview Station on the Transitway, just west of downtown.

High frequency rapid transit service is provided along the Transitway and other major corridors by 8 major routes, numbered between 94 and 106. On central parts of the Transitway, rapid transit buses travel every minute or two during weekday rush hours, and service is available 24 hours a day.

Transitway features include park & ride lots, stations, sales centres, and dedicated bus-only roadways.

Regular routes operate all day long, generally 7 days a week. At bus stops, regular service is indicated by black-coloured numerals on the bus stop sign.

Crosstown and mainline service is provided by black routes numbered between 1 and 118, which travel along major corridors throughout the city, connecting neighbourhoods and major destinations.

Regular local routes provide all-day service within a community, and connect the community to mainline or Rapid Transit service at a Transitway station. Local routes are numbered 120 to 199.

Express:

Express routes run weekday rush hours, and require premium fare. Express routes provide direct, quick trips from suburban communities to downtown and back during rush hours. At bus stops, express service is indicated by green-coloured numerals on the bus stop sign.

Rural Express:

Rural express routes provide a service similar to express routes and require premium fare.

These routes operate to and from communities outside the urban transit area, including: Cumberland Village, Carlsbad Springs, Gloucester South, Kars, Leitrim, Manotick, Munster Hamlet, Navan, North Gower, Notre-Dame-des-Champs, Richmond and Vars.

Peak-only routes run weekday rush hours only, but do not require Express premium fare. Peak routes, which are indicated by red numerals on bus stop signs, operate to major employment areas, including many industrial and suburban employment centres, as well as downtown.

School routes operate to and from primary and secondary schools. These routes are numbered between 600 and 699. Some local and other regular routes also have a few designated school trips operating on a portion of the route.

Routes numbered in 800-899 series, operate in the early-morning only, before 6 a.m.

PLEASE NOTE: Effective September 5, 2010, the 'early morning service' is being revised. The 800 sereis of routes are being cancelled and replaced with early monring trips on other routes. ... more info

Special events service is provided to Scotiabank Place for all major events, including NHL hockey games and concerts. The Scotiabank service — known as the Connexion 400 Service — is provided by routes numbered 400 to 406, and operates from major Transitway stations and park & ride lots.
Connexion 400 Service

Chartered service is also provided to other special events, such as the Winterlude Snobus.
Chartered bus service

Many communities outside the City of Ottawa have bus service that is not provided by OC Transpo, but is organized under a series of routes numbered in the 500's. Many of these services offer transfer agreements with OC Transpo services. Fares and schedules are set by the Rural Partner Company.
more info ...

STO operates buses within Gatineau, Québec and betwen Gatineau and downtown Ottawa. STO and OC Transpo have reciprocal fare and transfer arrangements which permit easy commuting using both systems.
» transferring between OC Transpo and STO
www.sto.ca