I live in Rapid City and commute to Spearfish. I leave RapidCity by 6 minutes after 8 and get onto I-90 at Exit 52. I must exitI-90 at Exit 12 by no later than 8:50 so that I am not late forclass. Normally, I can drive the speed limit and make it ontime.
Over the past few years there has been a lot of construction onInterstate 90. For example, last year 4 miles of road was underconstruction between Mile Marker 26 and 30 (Sturgis). The postedspeed limit in the construction zone (single lane -- do not pass)is 55 mph, but I always end up behind someone that is going only49mph. When I am not in the Construction Zone, what is the minimumspeed that I have to drive, so that I can be at Exit 12 by8:50?
