The TTC could be facing a “significant” budget shortfall this year if ridership numbers continue to decline, a new staff report suggests.

So far this year, the TTC has seen about four million fewer rides than what was previously expected, which could spell trouble for the transit agency if the trend continues.

The projected 2016 ridership total identified in this year’s budget was 553 million rides but the staff report says that due to the drop in ridership, it is estimated that the actual year-end number could be in the range of 540 million, 13 million fewer rides than projected.

That difference represents about a $30 million revenue shortfall.

Contributing factors to the disappointing ridership numbers include slowing employment growth, declining adult Metropass sales due to price hikes in 2014 and 2015 and a failure to attract more riders despite service enhancements, the report says.

What impact low gas prices and the increasing popularity of ride-sharing services have on the TTC is “difficult to quantify,” according to the report.

“The consensus opinion from GTA transit agencies is that the main driver of ridership is economic growth, in particular, employment growth, which is beyond the control of transit agencies and could potentially have a long-lasting impact on ridership growth,” the report read.

Among the possible actions under consideration by TTC management is a freeze on some previously announced service improvements until officials get a clearer picture of the ridership trend.

The specific service improvements that would be impacted by this is not clear.

The drop in ridership is not isolated to Toronto, the report says.

Transit services in Calgary, Edmonton, Ottawa, Montreal and Vancouver have also experienced a dip in ridership.

The staff report will be presented at the next TTC board meeting on March 23.