The go-to gripe for car owners used to be gas prices, but if you’re in King, Pierce or Snohomish counties, car tabs just became more of an expense.

Starting Wednesday, any vehicle registration in the Sound Transit taxing district will have to operate under a new motor vehicle excise tax (MVET), which will fund Sound Transit 3 (ST3).

The November 2016 vote to pass ST3 increased the MVET rate by 0.8 percent, bringing the total to 1.1 percent annually. That means a tax of $110 for each $10,000 of vehicle value, new or used.

These taxes are, of course, being put towards expanding the light rail system in order to make it more of a region-wide convenience. ST3 will extend the north-south tracks to Tacoma and Everett, and the east-west tracks from Redmond and Issaquah to Ballard and West Seattle.

ST3 also expands routes for rapid bus transit in key corridors, which will now run on Interstate 405, state Routes 518 and 522, and on Northeast 145th Street every 10 minutes during peak hours. Seattle RapidRide routes C and D will also see improvements while light rail construction is underway.

This tax increase came as a bit of a shock to some, after the “typical annual cost” calculated for these taxes ($43 extra per year, based on $5,333, the median value of vehicles in the taxing district) turned out to be lower than some actually owe.

"When I opened the bill and saw that it was about $1,000 more ... Of course my wife was in the car with me. Her first reaction was ‘We’re selling the car,’” Robert Klem, a Tesla driver whose tabs rose to $1,500 under the new tax, told KOMO News.

“I don’t think there’s anything wrong on this, it just may have been something that I wasn’t as informed as I should have been about.”

This tax actually occupies a uniquely weird history: Sound Transit's formula inflates the value of a car more than, say, Kelley Blue Book. The Blue Book says a 1-year-old car is worth 70 percent of its list price, whereas Sound Transit values it at 95 percent. 

The state Department of Transportation has said it's from a standardized valuation chart that Sound Transit adopted from the state after the passage of 1996's Sound Move (the light rail's first package). The state Legislature has already repealed the inflated valuation chart in favor of a more modest one, but thanks to a ruling from the state Supreme Court, the current inflated numbers will stay in use until Sound Moves' bonds are paid off in 2028. 

At that time, the remaining ST3 car tab taxes will be measured by the newer, more-modest valuation. 

These tax revenues make up just over half of Sound Transit’s total funding for this project, which totals $53.8 billion. Other funding comes from federal grants ($4.7 billion), existing Sound Transit taxes ($8.6 billion), fares and other revenues ($1.5 billion) and more.

This is the second wave of tax increases that came out of the 2016 ST3 vote, after property taxes were raised on Jan. 1. The final piece of the tax triumvirate – a one-half percent increase in sales tax – will come on April 1 (no joke).

According to Sound Transit’s calculator, the typical adult will see only a $169 increase via the new taxes, based on median values. But its website does have a special calculator that folks can use to check their actual cost.

These taxes – though higher than some were expecting – were designed by the Sound Transit board as a response to “strong public support” for broader mass transit investments. But ST3 obligates the board to roll all of these taxes back within seven years of ST3 completion (unless a future ballot measure directs otherwise).

The light, for now, at the end of the light rail tunnel will be ST3 completion in 2041. But drivers can at least look forward to less-inflated car valuations in 2028.