Reversible express lanes in Seattle, Washington

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Interstate 5 Express Lanes Auxiliary route of I-5
Defined by RCW 47.17.595, maintained by WSDOT
Length:	8.00 mi (13 km)
South end:	I-5 in Downtown Seattle
Major junctions:	Stewart Street/Howell Avenue Mercer Street NE 42nd Street (UW) SR 522
North end:	I-5 in Northgate
State highways in Washington < SR 4 SR 6 > Lists: current - 1937-70 - 1964 renumbering

Interstate 90 Express Lanes Auxiliary route of I-90
Defined by RCW 47.17.595, maintained by WSDOT
Length:	10.00 mi (16 km)
West end:	Airport Way S. in Downtown Seattle
Major junctions:	Island Crest Way
East end:	Bellevue Way in Bellevue
State highways in Washington < I-82 SR 92 > Lists: current - 1937-70 - 1964 renumbering

The Seattle Reversible Express Lanes are two sets of reversible express lanes serving traffic going in and out of Downtown Seattle. The express lanes serve Interstate 5 between Downtown Seattle and the Northgate neighborhood, and Interstate 90 between Downtown Seattle and Bellevue ^[1].

Contents 1 History 2 Route Description 2.1 Interstate 5 2.2 Interstate 90 3 Exit list 3.1 Interstate 5 3.2 Interstate 90 4 Operating hours 4.1 Interstate 5 4.2 Interstate 90 5 Future Plans 6 References

[edit] History

The first express lanes were created in the 1960s with the construction of Interstate 5 through Seattle. New ramps were eventually added and/or rebuilt with the increasing redevelopment of Downtown, including the Cherry Street/Columbia Street ramps and the ramps to the Downtown Seattle Transit Tunnel. The next set of express lanes were constructed on Interstate 90 in 1989. There were some controversy during the planning and construction of the express lanes, including concerns from the cities of Seattle and Mercer Island.

[edit] Route Description

[edit] Interstate 5

The Interstate 5 express lanes begin north of Yesler Way, with a one-lane ramp traveling towards under the northbound I-5 lanes to meet with the Cherry Street/Columbia Street ramp. The lanes continues to travel under northbound I-5 until the lanes emerge onto an elevated bridge at Mercer Street in the middle of I-5. At the Ship Canal Bridge, the lanes are depressed and travel below the mainline lanes until the lanes emerge from the bridge's first level. From there, the express lanes continues to travel in the middle of I-5 until its terminus at Northgate.

All vehicles are allowed to travel on the express lanes. However, some ramps are designated for HOV only because of several reasons. For example, the Cherry Street/Columbia Street/5th Avenue ramp is designated HOV only because the ramp is very narrow with no shoulders and has limited sight distance. Improvements cannot be made to this ramp because of the Key Tower above the ramp terminus and the massive reconstruction of I-5 required to expand and realign the ramp. The Ravenna Blvd. on-ramp is also designated HOV only because the merging lane from the on-ramp to the express lanes is not long enough to support more traffic from the on-ramp, and many other factors involving traffic flow around the area. Another ramp designated HOV only is the Pike Street/Downtown Seattle Transit Tunnel ramp because of fears that too much traffic coming on/off the express lanes will interfere with buses traveling in and out of the bus tunnel.

[edit] Interstate 90

The Interstate 90 express lanes begin in two locations, at the southern end of the Downtown Seattle Transit Tunnel and the signalled intersection at 5th Avenue S., S. Dearborn Street, and Airport Way S. The lanes turn east and travel in a separated right-of-way before traveling towards the middle of I-90 east of the interchange with I-5. This section is bi-directional, containing two lanes separated by a barrier, and allows buses to use the lanes in both directions at all times. From there, the lanes travel through the Mount Baker Tunnel and onto the Homer M. Hadley Memorial Bridge, sharing the bridge with the westbound lanes. From there, the lanes travel through Mercer Island and ends at its terminus with the I-90 interchange with Bellevue Way, with ramps connections to mainline I-90 and I-405.

When the I-90 express lanes were planned (along with I-90 itself), it was assumed that the express lanes would function as reversible HOV lanes. However, during the planning, the cities of Bellevue, Mercer Island, and Seattle were arguing over the proposed configuration of I-90, including number of lanes and function of the express lanes. This argument was one of the reasons why the western segment of I-90 wasn't completed until the late 1980s/early 1990s. Per an agreement with Mercer Island, WSDOT, and the Federal Department of Transportation in 1976, residents of Mercer Island were allowed to use the express lanes between Island Crest Way and east of Rainier Avenue (ramps to mainline I-90) without having to abide by HOV requirements. So, the segments of the express lanes between the western terminus to I-90 ramps and Island Crest Way and the eastern terminus are reserved for HOV only.

[edit] Exit list

[edit] Interstate 5

The entire route is in Seattle, King County.

Mile[2]	Destinations	Notes
165.29	I-5 south	South end of express lanes
165.62	5th Avenue, Columbia Street	Southbound exit and northbound entrance (HOV only)
166.49	Pike Street (Metro Transit Tunnel)	Southbound exit and northbound entrance (HOV only)
166.63	Stewart Street - Seattle City Center	Southbound exit and northbound entrance
167.20-167.26	Mercer Street	Southbound exit and northbound entrance
168.96	NE 42nd Street - University of Washington	Northbound exit and southbound entrance
196.66	Ravenna Boulevard	Southbound entrance only (HOV only)
170.54	SR 522 (Lake City Way) – Bothell	Northbound exit and southbound entrance
172.07	Northeast 103rd Street, 1st Avenue Northeast	Northbound exit and southbound entrance
172.43	I-5 north – Everett, Vancouver, BC	North end of express lanes

[edit] Interstate 90

County	Location	Mile	#	Destinations	Notes
King	Seattle	1.99	HOV entrance/exit only	Airport Way S., S. Dearborn Street
		2.21	Bus only	Downtown Seattle Transit Tunnel
		3.21	Bus only	Rainier Freeway Station
		3.66	N/A	Westbound I-90 to I-5	Westbound off-ramp only (All Mercer Island SOVs exit here)
		3.87	N/A	Eastbound I-90	Eastbound on-ramp only (All Mercer Island SOVs enter here)
	Mercer Island	6.58	7A	77th Avenue SE
		6.80	7B	Island Crest Way	All Mercer Island SOVs enter/exit here
		7.45	7C (HOV entrance/exit only)	80th Avenue SE
		8.01	HOV entrance only	Westbound I-90	Westbound on-ramp only
		8.39	HOV exit only	Eastbound I-90	Eastbound off-ramp only
	Bellevue	8.90	HOV exit only	I-405	Eastbound on-ramp only
		9.44	9 (HOV entrance/exit only)	Bellevue Way
Express lanes END

[edit] Operating hours

Because the express lanes' main purpose is to funnel traffic in and out of Downtown Seattle, operating hours have been set up for both sets of express lanes. The operating hours for the I-5 express lanes are more restrictive due to noise concerns from adjacent residential communities. The I-90 express lanes are closed once in a while for maintenance of tunnels. Operating hours for both express lanes may vary due to construction conflicts and/or events in Seattle.

[edit] Interstate 5

Monday - Friday

• Southbound : 5am - 11am
• Northbound : 12pm - 11pm
• Closed : 11pm - 5am

Saturday - Sunday

• Southbound : 7am - 12pm
• Northbound : 1pm - 11pm
• Closed : 11pm - 7am

[edit] Interstate 90

Monday - Thursday

• Westbound : 1am - 12:30pm
• Eastbound : 2pm - 12:00am
• Closed : Every other Tuesday from 10am - 1:30pm

Friday

• Westbound : 1am - 12:30pm
• Eastbound : 2pm - 12am (Saturday)

Saturday-Sunday No westbound during Saturday-Sunday; only eastbound.

[edit] Future Plans

With the growing traffic on I-5 and I-90, there have been many plans suggested for improvements for the express lanes corridors. One improvement project involves the I-90 express lanes. As part of Sound Transit's Phase 2 expansion project, the I-90 express lanes will be replaced with light rail tracks for the Link Light Rail East Link. Many have been concerned with this project because they fear that the loss of the express lanes will add more congestion onto the mainline. Despite that, the project continues to move forward, with the construction of the replacement HOV lanes and direct-access ramps on the mainline. On Interstate 5, the only planned improvement on the express lanes is a direct connection to the future SR 520 HOV lanes, to be constructed as part of the Evergreen Point Floating Bridge replacement project.

[edit] References