Ottawa is notable for its Transitway system, a network of grade separated busways linking outer suburbs to the downtown core which originally opened with five stations in 1983, and continued substantial expansion into the late 2000s.

[10][11] The Transitway fans out from the city centre in four directions: east, southeast, southwest, and west, extending past the greenbelt and entering the outer ring suburbs of Kanata, Barrhaven, and Orléans.

[12] The horsecar would remain a staple means of public transportation until 1891 after Thomas Ahearn founded the Ottawa Electric Railway Company.

[20] However, studies in 2003 and 2004 found there to be lingering elements of a negative work environment,[20] and employee-management communication was reported to be strained following the 1996 strike.

[17] OC Transpo launched the O-Train diesel light rail transit (DLRT) service on 15 October 2001, as a pilot project.

The service consists of one north–south line, with major points of interest including Carleton University and the South Keys Shopping Centre.

OC Transpo drivers, dispatchers, and maintenance workers under Amalgamated Transit Union local 279 went on strike 10 December 2008, at 12:01 am.

Rona Ambrose, the Federal Minister of Labour ordered a union membership vote on 8 January 2009, on the city's contract proposal[22] in response to a request from mayor Larry O'Brien.

[30] On 18 September 2013, a double-decker OC Transpo bus, running on Route 76 from Barrhaven to downtown at 8:48 a.m., collided with a Toronto-bound Via Rail passenger train at a level crossing, equipped with active warning systems, near Fallowfield Station in Ottawa's southwest end.

On 16 March 2020, as a preventative measure during the COVID-19 pandemic, OC Transpo began limiting front door boarding and seating to riders with accessibility needs.

[40] On 19 September 2021, a train with passengers on the Confederation Line derailed before entering Tremblay station after two axles became dislodged from the second car.

This, combined with decades of underinvestment and thinned resources, has led to OC Transpo having a poor ridership recovery rate from before COVID; sitting at only 70% as of 2023.

However, on 14 December 2006, City Council led by Mayor Larry O'Brien cancelled the north-south light rail expansion project.

This new project envisions fully grade separated rapid transit service on the original Transitways from Baseline station or Moodie dr. in the west to Trim Park and Ride in the east.

The gap between the east end west branches of Transitway will be replaced by a new downtown Subway tunnel under Queen and Rideau streets with three underground stations.

The decision to convert the BRT network to rail was chosen due to trains being significantly more cost effective for the capacity needed, and an underground bus tunnel being completely impractical for the scale of service required.

[54][56] In 2022, OC Transpo began a pilot project where it would pre-emptively pull articulated buses out of service, if 30 cm of snow or another severe weather event was predicted.

[57] Line 1's Citadis Spirit trains, custom built by the French rolling stock manufacturer Alstom, have been riddled with issues, and have garnered a bad reputation by both media and the public.

In the first two years of service, they suffered repeated faults, including, among other things, derailments, computer failures, and cracked wheels.

[58] The Ottawa Light Rail Transit Public Inquiry report found that there were several causes for the vehicles' poor reliability.

In addition to this, the OC Transpo workforce was inexperienced operating the vehicles, and the construction and testing of line 1, as well as the trains that run on it, was heavily rushed.

Some of the older New Flyer D60LF sixty-foot articulated buses have caught on fire during the summer of 2006 and the Summer/Fall of 2010, due to overheating engines, effectively putting them out of service.

They were added to the fleet primarily for their higher seated capacity compared to the articulated buses in use (86 versus 55), and are employed mainly on commuter oriented "Connexion" routes.

[70] An expansion fleet of 38 Alstom Citadis Spirit LRVs will also be built for the Stage 2 vehicle additional requirements for use on Line 1.

[71] OC Transpo currently has 5 bus garages and two rail yards that house the fleet, and are also where vehicle maintenance is carried out.

[82] On 18 January 2013, OC Transpo starting the final testing of its Presto Card deployment as part of the NEXT-ON program.

The database was originally refreshed every night with updates of the day's Presto fare purchases when the buses return to the garages; this required users to wait up to 24 hours before cash loaded onto their card accounts is recognized by the readers.

Unlike the TTC and GO Transit facilities, OC Transpo did not launch full Presto ticket machines until November 2017, when all O-Train Line 2 stations except for Bayview featured a new fare gate system.

In January 2021, OC Transpo launched the Bikesecure program which allows secure bike parking spots at a select number of transit stations to be reserved for a monthly fee.

Service is provided directly to the residences of eligible users who book trip appointments with a call centre at least one day in advance.