The 903 Express bus replacing the former Scarborough Rapid Transit Line 3 began operating formally in September 2023 after the SRT shut down in July. Initially the route operated totally in mixed traffic, but red lanes were added to speed operation. Also, the route initially operated via Progress, but shifted to Ellesmere in mid-November after roadway changes to support the route.

Initial service was extremely frequent, but this was cut back in November 2023 when several other routes were extended south from STC to Kennedy Station to provide a one-seat ride to passengers who otherwise would have to transfer at STC station. The 903 Express remains in operation, but less frequently thanks to the presence of other services.

Although many routes now share the corridor south via Midland and north via Kennedy between Ellesmere and Kennedy Station, the 903 Express can stand in for all routes to measure travel times.

A few points revealed here:

• Service on this route is fairly regular with much less of the headway spread into gaps and bunches seen on other route analyses. This is likely due to the demand pattern with few stops, and less cumulative delay from boarding/alighting passengers along the route, combined with reliable departures at the terminals.
• Where buses are crowded, this usually shows up as a series of regularly spaced vehicles with heavy loads, not as single crowded buses after wide gaps.
• The benefit of the red lanes varies by location, direction and time of day. Travel times are included here as a reference point for future comparison when the SRT busway goes into service, as well as to track any spillover effects from Scarborough Subway construction.

Updated November 9, 2024 at 4:40pm: The operating chart including crowding status has been added for October 16 as a counterpart to the bus spacing charts for the same day.