GO Transit is reminding passengers that, starting today, Monday, June 18, they’ll be “adjusting” parking at Clarkson GO Station, as contractors start building a new 1,200-space multi-level parking structure on the northwest corner of the giant south lot at the station.

GO is relocating the former reserved parking area in the south lot to the northern and southeastern sections of the south-side lot. It’s also refunding $70 for June to passengers who usually use those spaces.

It will also make about 40 temporary parking spaces available at 2120 Bromsgrove Road — on the north side of the station off Southdown Road.

The Toronto Star’s Tess Kalinowsky reports that, in fact, GO is eliminating about 300 parking spots for the next 18 months. However, when the contractors have completed the new lot, the total number of spaces at Clarkson will increase to 4,008, up from 2,878.

According to the Star, “GO admits it will make capacity issues at the station worse. Commuters who arrive past 8 a.m. frequently struggle to find a parking space in the vast lots.”

GO is encouraging commuters to consider walking, cycling, carpooling or riding MiWay or Oakville Transit buses to the station, instead of driving.

The Star explains that about 4,000 commuters use Clarkson during the morning rush hours, making it the third-busiest station in the GO system, after Oakville and Whitby. GO expects that number to grow by about 700 within a decade.

GO recently opened more carpooling spaces at Clarkson. Forty-six of 112 registered GO carpooling participants are at Clarkson.

It hopes to open the new garage late next year or in early 2014. It will be the second-largest in the GO system — only Pickering’s 1,700-space facility, also under construction, will be larger.

Since GO is providing less parking at Clarkson, it’s set up an information booth inside the station building where staff can answer any specific questions you may have about parking at the station.