OK, I am out getting some practice on my new TBA. I have a great time out around Mt. Rainier and heading towards Yakima, WA. On the way back, I decided I needed some practice on highways and took I-90 (westbound) back across the mountains and into the Seattle area. I am zipping along 60-70 mph (depending upon my comfort level). Then, I get the warning signs about grooved pavement ahead and Motorcyclists take extreme caution, etc... Then I hit the grooved pavement. That was the most terrifying moment I've had on the bike

. The grooves just grabbed the front wheel and I dropped down to 40 mph, wishing I had blinkers to warn people behind me. This went on for about 2 miles (??). Cars were flying up behind me and there I am doing 40 and trying to not feel like I am going down.
How do you more experienced bikers deal with it? Should I have just kept my speed up and assume I would not be wrenched over? Fortunately, it's a repaving job so the state might have it resurfaced in a year or three. Until then I'm going to just avoid I-90 westbound.
I'm assuming that metal grate bridges are the same? I think we have a few around here that I need to identify before trying to go over them.
Advice anyone? Thanks very much.
Steve