The Maryland Transportation Authority is warning of "significant delays" at the Bay Bridge this Labor Day weekend as travelers grasp for a last few precious hours of summer beach time.
The authority is predicting that 366,000 vehicles will traverse the bridge between today and Monday.
By a simple count, that would make the bridge the third-busiest of Maryland's toll facilities this weekend. The authority is projecting that the Fort McHenry Tunnel will carry 473,000 vehicles this weekend - edging out the 467,000 on the toll road stretch of Interstate 95 northeast of Baltimore.
But raw numbers can be deceptive. The Fort McHenry Tunnel, for instance, has a total of eight lanes, while the Bay Bridge has five.
So each lane of the Bay Bridge will be carrying an estimated 73,200 vehicles this weekend, compared with 59,125 at the tunnel.
And while tunnel traffic flows relatively evenly in both directions, the bridge experiences an eastbound surge on Friday evening and early Saturday, followed by a westbound exodus on Monday - typically with three lanes to handle the prevailing traffic.
Those facts of life on the Bay Bridge help explain why the authority issued advice Thursday on when to travel to avoid the resulting backups. According to the agency, the times to travel are:
* Today, before noon and after 10 p.m.
* Saturday, before 7 a.m. and between 5 p.m. and 10 p.m.
* Sunday, between 7 a.m. and 11 a.m. and after 10 p.m.
* Monday, before 11 a.m. and after 10 p.m.
Overall, the authority expects traffic counts at state toll facilities this weekend to increase 3 percent over previous years' totals. The agency is expecting 533,000 vehicles to use its other facilities, including the Harbor Tunnel, the Key Bridge, the U.S. 301 bridge over the Potomac River and the U.S. 40 bridge over the Susquehanna.
The authority is calculating the percentage increase based on 2008 figures for most toll facilities but 2007 totals for the Bay Bridge, where repair work in the wake of a high-profile fatal crash skewed last year's totals.
After the weekend, Bay Bridge travelers will face a new set of challenges. The authority plans to close the westbound span of the Bay Bridge for deck replacement work four nights next week, requiring two-way operations on the two-lane eastbound span.
The agency said it will close the newer, three-lane westbound bridge Tuesday, Wednesday and Thursday nights at 9 and reopen at 5 a.m. the next day. On Sept. 12, the span will be closed at 10 p.m. and will reopen at 7 a.m.
The westbound span will be the site of daytime work Wednesday, when one lane will be closed between 9 a.m. and 2:30 p.m. for maintenance.
The authority urges motorists to slow down where steel plates are being used as part of the bridge surface. There may be periodic lane closings of up to 30 minutes during off-peak hours as workers inspect those plates.