"Underutilized" is a pretty iffy measure when comparing parking to bike lanes. Let's say 10 drivers can park on one side of a city block. Their cars will be parked for an average of 2 hours, and will carry 1.5 passengers. The parking is heavily contended for 14 hours. Given these rough estimates, 105 people will benefit from the parking each day. How many cyclists need to use that same land per day to be considered properly utilized? 200? 500? The fact that a bike lane isn't congested doesn't mean it's underutilized relative to parking.

And let's not forget that bike lanes are a public good, while parking spaces can be (and are) provided by private businesses. For that matter, the city could provide public lots or garages that are off the road. Parking does not need to be curbside.

The point is that parking is something which can be provided privately, and which should, in theory (I know that, especially in economics, this doesn't necessarily mean in practice), cost approximately the same. Bike lanes, on the other hand, cannot be provided privately.

...which means it should go to referendum, rather than be subjected to executive decree.

Isn't there some sort of city council that decides this sort of thing, rather than a sole executive? Most public works projects don't go through a referendum from what I've seen, which would be impractically unwieldy.

Imagine if they tried to hold a referendum every time they wanted to put in some street parking...