Does monorail still make sense for Seattle?

I think so.

Instead of arguing about the appropriate length of the financing plan and the future value of money, I will focus on the fundamental transit arguments. Do we want rapid transit in Seattle at all? Yes. Rapid transit systems always pay off in the long run with increased economic activity, property values, and quality of life. So what kind of rapid transit should we build? Let's compare.

Speed. A rapid transit system must be faster than cars or most people won't use it. It should cruise at 40 or 50 mph (or more) through town. It should not impede cross traffic. Surface light rail or bus rapid transit requires overpasses and underpasses for all cross streets if it is to be fast and safe. Even with synchronized lights, trains and buses cannot safely speed through intersections. Sound Transit's light rail will be fast where elevated or underground, but it will have to slow down where it intersects with surface streets. Everyone, riders and cross traffic, moves fastest if the system is mostly elevated or underground.

Frequency. Vehicles should arrive no more than 10 minutes apart (an average wait of five minutes), so that people do not need schedules and can make quick connections at the stations. Most people will shun any system with long waits. Monorail and light rail have short waits. Bus rapid transit may have long or short waits, depending on implementation. Existing buses have long waits.

Construction Cost. Tunnels cost so much we can only realistically expect to build a few miles. Elevated transit is much cheaper but just as fast. Elevated light rail and elevated busways cost more than monorail. Monorail can piggyback on the existing West Seattle Bridge, but light rail will need a costly new high-level bridge. Surface buses and trolleys are cheapest but slowest.

Operating cost. Monorails cost least because they need no drivers. Buses cost most because they have the most drivers. Remember, in the long run, the indirect economic benefits of any rapid transit system always outweigh the construction and operating costs.

Capacity. A transit network should have high-capacity trunks, medium-capacity branches, and lower-capacity feeder lines. High-capacity light rail is good for the trunk line from SeaTac to downtown to Northgate, eventually extending to Tacoma and Everett. Medium-capacity monorail is good for branch lines from West Seattle to downtown, Ballard to downtown, and Ballard to Northgate. Low-capacity buses and trolleys are good for shuttling people to and from stations.

Aesthetics. All fast transit has aesthetic problems. Elevated light rail, elevated busways, and monorail all have columns and guideways, but monorail's are least massive. Fast surface transit needs massive dedicated lanes, overpasses, and underpasses. Subway riders have no views. At least riders of elevated systems have good views.

The fundamental arguments haven't changed. Monorail does well in most categories, and still has its place in the mix. Is the truncated line still long enough to be worth it? Yes. Every rapid transit system grows over time with extensions and new lines.

The monorail now before Seattle's voters is still a good branch to add to Seattle's transit network.

Keith Enevoldsen is a resident of the Arbor Heights neighborhood.