The Issaquah City Council unanimously passed a simplified transportation concurrency plan at its regular meeting Tuesday night.

Transportation concurrency, as dictated by the state Growth Management Act, requires cities to manufacture a procedure for how they mitigate traffic impacts from new development and update said procedure periodically.

The new plan, written by Issaquah’s development services department over more than a year, moves the city away from a system with which it examined intersections and projects individually toward a “system-wide” predictive model.

“It’s much simpler for us, much simpler for staff and moves us to a more holistic approach,” Development Services Director Charlie Bush said.

Additionally, the updated plan raises the traffic impact fees levied on developers. Kristi Triple spoke on behalf of Rowley Properties to express the Issaquah developer’s support for the plan and what it could do to address crowded roads in the city.

“It’s not a secret that traffic congestion is the biggest problem facing citizens and business alike,” she said.

Kathy Orni of Kirkland’s YarrowBay Group wanted to ensure the new plan would not change the terms of development projects in-progress.

As reported last week, the existence of the Central Issaquah Plan complicated transportation concurrency due to the anticipated growth and associated costs in the middle of the city.

Though he said he would vote for the plan update, Councilmember Joshua Shaer warned that the city should avoid hastening into “a valley of walls and towers” without a plan to pay for future road projects.

Meanwhile, Councilmember Nina Mulligan recalled discussing transportation concurrency with development services from the moment she was appointed to the position in February.

“This is a satisfying moment and I’m so glad to be voting in favor of this,” she said.

She added that she hoped by factoring in the anticipated future road costs of the city — which the city did, though it wasn’t a requirement of the Growth Management Act — the voters would develop an “appetite” for future transportation funding measures.