Motorists will be left with few options after TransLink announced Thursday it will be restricting traffic on the Pattullo Bridge for 18 months to undertake $100 million in major repairs next summer.

Starting mid-year in 2016:

One lane will be open in each direction during weekdays.

The bridge be closed at night and on weekends.

Heavy trucks with more than three axles will be prohibited.

The sidewalk will be closed to pedestrians and cyclists for the duration of the work.

TransLink acknowledges many drivers will be forced to take the tolled Port Mann Bridge, the Alex Fraser Bridge or find alternate routes.

"Pattullo Bridge users should start planning ahead and thinking of alternatives, such as using other crossings, transit, carpooling, or traveling outside of peak periods," the authority said in a statement.

TransLink says the bridge averages between 60,000 and 80,000 trips a day or about 28 million trips a year.

In January 2009, a two-week closure of the bridge due to a fire caused traffic backups on the Port Mann Bridge, the Alex Fraser Bridge and at the Massey Tunnel.

TransLink says the 78-year-old bridge, one of the oldest in the region, needs comprehensive deck rehabilitation and seismic upgrades to maintain its safety.

Up until now the bridge has been maintained with patch jobs through a series of summer closures, but TransLink says major repairs are now needed to keep the bridge safe.

TransLink's transportation plan, which could be funded if the transit referendum passes, calls for a new four-lane crossing that could be expanded to six lanes.

TransLink says the lane closures were developed following months of analysis and consultation with the cities of Surrey and New Westminster, the B.C. Trucking Association, the New Westminster Chamber of Commerce, first responders and Port Metro Vancouver.