$15 tolls start March 1 on I-405 and SR-167

Using the tolled carpool lanes on Interstate 405 and State Route 167 near Seattle is about to get more expensive.

Why it matters: For solo drivers, the maximum toll rate to enter the carpool lanes on each highway will rise to $15 starting March 1. That's an increase of $5 to $6 from current rates.

Plus: Minimum tolls are going up to $1, and tolling hours will last an hour later on weekdays, through 8pm.

The big picture: Highway construction projects on SR-167 and I-405 face major funding shortfalls , which the increased toll rates will help address, the Washington State Department of Transportation wrote in an email to toll pass holders this week.

State of play: Right now, drivers pay a maximum toll of $9 on SR 167 and $10 on I-405 to enter the HOV lane if they don't meet carpool lane requirements.

• I-405 requires at least three people in a vehicle during peak hours to avoid a toll in the HOV lane, while SR-167's HOV toll lanes require at least two people.

What they're saying: Raising the maximum tolling rates to $15 is also designed to "discourage too many cars from entering the lanes," the transportation department wrote.

• That in turn will "improve travel time reliability," the agency said.
• Toll rates in the HOV lanes are based on the speed of traffic, with tolls lowest when traffic flows smoothly.

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