I-5 Express Lanes Built To Prevent Bottlenecks

This is the third of a series of articles dealing with questions you've commonly asked about I-5. The answers are from Leslie Salisbury of the state Department of Transportation. Earlier questions appeared Wednesday and Sunday.

6. How do the Express Lanes operate?

Answer: ``Any veteran motorist can tell you that on-ramps and exits are points of congestion. The Express Lanes were constructed to provide through traffic a minimum of bottlenecks, thus, there are a minimum number of ramps to and from them.''

``The current operation schedule is: Monday through Friday - southbound 5:30 a.m. to 9:30 a.m. Monday through Thursday - northbound 2 p.m. to 5 a.m.

``Friday through Sunday - southbound 5:30 a.m. to 9:30 p.m.

``Northbound 10:30 a.m. Friday to 5 a.m. Monday.

``The weekday window between 9:30 a.m. and 2 p.m. allows contractors access to their construction projects on the mainline and in the Express Lanes. Without this access, contractors would need to use mainline lanes, thus significantly disrupting traffic.

``The Department of Transportation controls the Express Lanes. Real people really do sweep through the lanes . . . for each transition.

``This takes about 30 to 45 minutes to complete. The sweep is done partly because the closed-circuit television cameras can't show us everything, including all of the gates, to be sure they are in the proper position. The gates are operated manually instead.

``The sweep is also important to find any disabled vehicles that may have been abandoned. The State Patrol is called to arrange for these vehicles to be towed immediately because traffic will soon be moving in the opposite direction. At best, abandoned vehicles pointed the `wrong' way would be a dangerous distraction for traffic, and at worst, the motorist might attempt to make a U-turn on the freeway.''

7. Why is there just the one-lane exit from southbound I-5 to I-90? Why is it from the left lane rather than the right? Why is the ramp banked the way it is?

Answer: ``It is a two-lane ramp from southbound I-5; these lanes . . . merge into the ultimate three-lane configuration on I-90. If the ramps from both northbound and southbound I-5 were each two lanes wide, there would be a conflict at the merge point.

``The ramps themselves are banked properly according to curve and assigned speed. If they were banked any steeper, they could become quite slippery, particularly if icy. Motorists who have troubles negotiating the curves need to observe the posted speed limit.

``Regarding the left-side ramp, the ramps in the I-90/I-5 interchange were built in the 1960s and designed in the 1950s. When the department finally was given the go-ahead to complete I-90, it chose to incorporate these `ramps to nowhere' rather than tearing them out and asking taxpayers to pay for new ones. And, according to the standards of 1950s highway design, left-side ramps were acceptable.''

(Keep reading. We have more questions, and more answers - in the Wednesday paper.)

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``Getting There'' appears Sundays and Wednesdays in the Northwest section of The Times.