on demand at other times. The bridge openings last for an average of four minutes from when traffic stops to when it resumes again. Most of the openings are for sailboats, as most of the tugs that operate this far east are able to pass under the bridge in its closed position. The bridge creates a bottleneck for traffic heading to and from State Route 520 (SR-520), and the creation of alternate routes has been proposed multiple times over the years. Traffic can become backed up for more than a mile when the bridge is open, as can be seen in aerial photographs. Plans to replace SR-520 include adding a second bascule bridge across the Montlake Cut next to the current Montlake Bridge. Historical significance The Montlake Bridge is celebrated as the site of boating season's "opening day" festivities the first Saturday in May. The bridge was constructed by the city of Seattle at a cost of $670,000. The steel was fabricated and erected by the Wallace Equipment Company. A. Munster, acting bridge engineer of the City of Seattle supervised the construction, J. D. Blackwell was city engineer and D. W. McMorris was assistant engineer. The bridge and the Montlake Cut together are a City of Seattle Designated Landmark (ID 107995), and the bridge was added to the National Register of Historic Places in 1982, as well as the Washington Heritage Register. It is owned and operated by the Washington State Department of Transportation. Navigation Montlake Bridge has two traffic lights one on either side of the Montlake Cut. These traffic lights are lit for large commercial traffic and if seen red small vessels need to proceed with caution of oncoming large commercial vessel. Height restriction are listed at at center and all together, with a clearance width of and in the open position. This bridge can be hailed on channel 13 or using appropriate horn request, of one long and one short, for an opening. Normal bridge opening restrictions Monday through Friday except federal holidays differs here than all the rest of the drawbridges on the Lake Washington Ship Canal. Restrictions are from 7 a.m. to 9 a.m. and from 3:30 p.m. to 6:30 p.m. from April 30 to September 1 and from 7 a.m. to 10 a.m. and from 3:30 p.m. to 7:00 p.m. from September 1 to April 30. Additionally, the draw may only open on the