Of the all possible High Capacity Transit corridor projects in Seattle’s Transit Master Plan, nothing carries more riders than a fast streetcar from downtown to Loyal Heights via Ballard and Fremont. Up to 26,000 riders per day could use this line in 2030, which would run a train train every 8 minutes at the peak, 15 minutes evenings and weekends, and 10 minutes the rest of the time and save the average traveler about 8 minutes over the current situation.
On the other hand, the 7-mile rail corridor would cost $327m in capital, well out of range for Seattle without outside assistance. It also would run less frequently than the BRT option, which costs $111m, draws 21,000 riders and is cheaper overall per new rider ($3.11 vs. $4.53). Enhanced bus takes up the rear at $4.74.
Nelson/Nygaard looked at constructing a ship canal crossing. They estimated the cost at $50-70m, but judged it to not meet cost/benefit considerations.