'Biggest event in years' is coming to downtown Detroit. Here’s what you need to know:

The NFL Draft in Detroit is two weeks away and city officials want to be loud and clear about one point: This event will be massive and like no other the city has hosted in recent memory.

With that will come traffic and parking headaches if you don’t plan accordingly, officials warn.

Over a three-day stretch from April 25 to 27, the city will be jammed.

“We're going to see 300,000 people down here on Thursday night. We don't have a sense of the magnitude,” said Mike Duggan, the mayor of Detroit.

People from across the United States and Canada will be coming for the NFL Draft, a spectacle Detroit’s mayor warns is nothing like a Taylor Swift concert or Lions game.

“You're going to need to think about an experience that's different than you're used to going to a football game,” Duggan told reporters at a media conference Thursday afternoon in Detroit. “And unless you're going to be here at nine or 10 in the morning, the idea of driving into downtown and parking is probably not realistic.”

Detroit officials are encouraging people to plan ahead, book parking spaces beforehand and arrive early.

If you plan to arrive after 10 a.m., they don’t think parking will be available, an people should instead use public transit like the Q-line, people-mover, the city bus or fan shuttles.

“This is going to be the biggest event we've seen in many, many years. The only thing I'm nervous about is the weather and we can't control it,” said Duggan.

The Ambassador Bridge and Windsor-Detroit Tunnel will be open throughout the event, but the John C. Lodge in Detroit as well as Jefferson Avenue will be closed and event planners expect traffic will be congested.

“We've been working with the tunnel, working with Customs Border Patrol so that on both sides of the border we know what to expect for all the great fans over in Windsor that we know are equally supportive of the Lions as the Detroiters here,” said Sam Krassenstein, the City of Detroit’s chief of infrastructure.

Windsor tourism officials are ready to capitalize off the event, which will surely have a spillover effect on this side of the border.

“We're very, very fortunate to have this two-nation destination concept working with our friends, Visit Detroit, because we recognize the fact that their geographic advantage and our geographical advantage is a benefit to all of us,” said Tourism Windsor Essex Pelee Island CEO Gordon Orr.

Detroit hotels are booked solid, but Orr said Windsor still has limited occupancy remaining for Friday and Saturday nights.

His best advice for people crossing from Canada for the festivities is take the tunnel bus.

“We're enhancing the hours of operation and the frequency and it's going to be a sight to behold and it's going to be the best way to go. If you're on the Canadian side of the border,” said Orr.

If you do drive across, officials suggest you pack your patience.

“There's a whole lot of people and the focus is really making it a great fan experience,” said Tal Czudner, the CEO of Windsor-Detroit Borderlink. “And when you're coming back, you might want to just go to the bathroom before you jump in your car and come back.”

WHAT ROADS WILL BE CLOSED?

The next phase of road closures in advance of the NFL Draft will begin Monday, April 15.

It includes the closure of eastbound and westbound Jefferson Avenue in front of Hart Plaza for the build out of the NFL Draft Experience, which is a free fan festival taking place during the entire event.

Phase three closures will begin Monday, April 15 at 12am and last until Monday, May 6 at 5am:

* SB M-10 exit to Jefferson Avenue downtown will be closed - Exits 1A (W. Jefferson) & 1B (Larned) will remain open at this time

* Westbound Jefferson Avenue from Beaubien Street to Washington Blvd.

* Eastbound Jefferson Avenue from Washington Blvd to Randolph

* Bates Street from Jefferson Avenue to Atwater Street

* Atwater Street from Civic Center Drive to Bates Street

* Southbound Brush Street between Larned Street and Jefferson Avenue

* All Tunnel traffic must use I-375 during the M-10/Jefferson Avenue closures

* Windsor-bound traffic should use Jefferson to Randolph to access the Tunnel

Public Street Closures for NFL Draft

Phase two closures began Monday, April 8th and will last until May 5:

* Northbound Woodward Avenue from East Congress Street to State Street

* One lane of Southbound Woodward Avenue on the West side of Campus Martius

* Eastbound Cadillac Square from Woodward Avenue to Randolph Street

* Westbound Cadillac Square from Randolph Street to Bates Street

* Bates Street from Cadillac Square to East Congress Street

Phase one closures began Friday, March 29th and will last until May 7th:

* Randolph Street between Gratiot Avenue and Fort Street

* Monroe Street between North Woodward Avenue and Randolph Street

* Farmer Street between Randolph and Bates (Garage access only)

* Bates Street (no through traffic)

Important parking information

Access to the Ford Underground Garage will remain open through Tuesday, April 23.