Los Angeles is about to unveil one of the most consequential transportation projects in recent history.  I don’t want to get too hyperbolic, but the coming of the Expo Line light rail transit tomorrow to Santa Monica is, as our current vice president might say, a big f***** deal.

The reason for the import is twofold: first, the location.  The westside of Los Angeles County is the most densely populated in the region and the most traffic-choked.  Expo, running from downtown Los Angeles all the way to the beach, will finally open that area up to the rest of the train network that’s been growing in fits and starts since 1990.  That means a good ridership boost for the whole system and a major alternative to driving for many westside residents and workers.

Second, and more intangibly, the train will now serve an influential part of the population, who will finally be seeing a train in their backyard, and a highly visible location for tourists and Angelenos alike.

Some of the most wealthy and powerful people in Los Angeles, from business to media to opinion leaders, reside in the westside.  They are the ones who set much of the tone for the region in its popular discourse and are key to much of its politics and private investment, particularly during a time of tremendous income inequality.  As opinion shapers, it matters if they complain about LA “not having any transit” (leaving aside the comprehensive bus network), so a train in their backyard undermines that claim.

In addition, with trains running through the streets of Santa Monica and along Interstate 10, this line will be a visible symbol of the ongoing transformation in Los Angeles’s housing patterns, transportation options, and self-image.  Some of the most powerful people in the region will be seeing it firsthand, as well as the legions of tourists from around the world (and the region) who visit downtown Santa Monica and nearby areas.

Ultimately, actions and investment matter more than symbols, and the everyday county voter has certainly been the key to funding these investments.  But images and impacts are mutually reinforcing, and the symbolism of Expo — as much as the ridership boost and potential for neighborhood development along the corridor — may matter just as much in the long run.

All in all, it makes tomorrow a momentous day in the history, and future, of transportation and development in Los Angeles.