LOS ANGELES (CBSLA.com) — Parking problems are looming over what could be a great day for Los Angeles commuters.

On Friday, Metro will open the final stretch of the Expo Line. It will carry passengers from downtown LA to Santa Monica and back, potentially relieving the gridlocked Santa Monica Freeway.

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Metro is hoping drivers will get on board, but that could be tough for anyone who doesn’t live within walking distance of a station. Only three of the new stations opening Friday provide parking, and the number of available spaces is fewer than 600. During the morning rush, those spaces will go fast.

Parking is in short supply all over Metro’s expanding rail network. The San Gabriel Valley Gold Line extension opened in March, reaching Azusa. The line is a welcome alternative to the clogged 210 freeway. There are parking garages at both Azusa Gold Line stations, but on weekdays, they fill up by around 7 a.m.

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Desperate drivers ditch their cars in store parking lots or on residential streets, creating a parking hassle for neighbors and businesses.  Azusa has issued plenty of tickets, and new parking signs are on the way.

Metro is asking riders to walk, bike, take a bus or use Uber to get to stations where parking is at a premium.

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Planners also hope people will live and work closer to rail lines in the years ahead.