I'm sort of disappointed no one found the fatal flaw in the 'Route D1" option I like so much. So I'll tell you: That option proposed sending the cars counter-clockwise around the loop, which would have required the cars to go through the center of what is now the monument plaza (there used to be a right-turn lane the streetcars would have commandeered). Seriously, check out the colored-pencil pictures - the car is going
through the plaza. Obviously this can't be done now that the plaza has been expanded. And so, I propose to you route
D2!
Let me show you its features!
First, instead of going counter-clockwise around the block, the tracks cross over each other so that the cars go clockwise around the blocks, making only right-hand turns. That adds efficiency, but it also will be helpful near the plaza, which I'll get to in a minute. First, since the cars require a turning radius of about 80 feet, the curve north will place the northbound track right up against of the east side of McClelland Street, taking what used to be parallel street parking. This should be in an exclusive lane, with a concrete curb to keep cars out.
Then, when the line gets to Elm avenue, it will need to switch from the east edge of the road to the west edge, in preparation for making the turn onto 21st south. This will require a new traffic signal at the intersection of Elm Avenue and McClelland street:
At this point the cars will be running against traffic on McClelland street - so an exclusive lane is absolutely required. Other streetcar systems operate like this already, notably the Tampa Florida line:
Now comes the plaza! The 80-foot radius curve just barely fits; a new traffic signal will probably be needed here too. On 21st south, the streetcar operates in a shared lane, in mixed traffic. This is the other important reason the cars need to go around the loop clockwise - so that they will be going in the same direction as traffic on 21st South. The stop at the plaza will be just like the buses already on 21st south- the streetcar will stop in the middle of the travel lane to let passengers board/disembark. In fact, it could share the bus stop/shelter that was recently installed there. Then, after stopping at the plaza, it will turn right onto Highland Drive.
At this point, the cars will be going southbound on Highland Drive down a new center median. Highland Drive will need a road diet - down from the 2 car lanes in each direction to a car land and a bike lane in each direction, plus a center median:
Then, all that is left is for the cars to turn right onto the S-Line corridor again. A new signal will be required to get the streetcars out of the center median; this new signal can also be used as a crosswalk for Parley's Trail headed towards Sugarhouse Park:
All in all, this route does not need to take any private property or demolish any buildings, like route D1 required. It fits entirely within the existing roads. It takes half the parallel parking spots off of McClelland Street, it requires a road diet for Highland Drive, and it may add a little more congestion to the bus stop at Monument Plaza, but these are all little things.
The total length for this line is just over 3,200 feet long. In comparison the new double-track between 300 and 500 East is 1,500 feet long. So we're probably looking at something about $12 million. Perhaps a little more, since there will be a few more traffic signals added in (McClelland and Sugarmont, McClelland and Elm, McClelland and 21st South, and Highland and Sugarmont - 4 total) and some will need to be reconfigured (21st South and Highland, Highland and Wilmington - 2 total).
The point is that this could be done very easily, without any new major innovations - and for about 5x less than what the crazy elevated airport extension will cost.