Round two of Seaside School District’s presentation to the city’s Planning Commission saw construction traffic and site access as key discussion items. Heavy truck traffic could rupture or damage city roads with thousands of trucks carrying rock and concrete expected during the construction process, commissioners said at Tuesday’s meeting. The city could see “alligator” effects to the asphalt from the many trips during the construction process.

The district’s conditional use permit request includes plans for expansion of Seaside Heights Elementary School and construction of middle- and high-school facilities on 89 acres to the east of the elementary school, approved by voters in November 2016.

Based on the projected trip generation of the campus after relocation of Gearhart Elementary School, Broadway Middle School, and Seaside High School, district traffic consultants estimated that Spruce Drive will carry a total of almost 4,000 daily trips. “This amount of traffic is not considered unreasonable, for roadways classified as major collectors in urban areas, which can carry upwards of 7,000 average daily,” according to the Lancaster Engineering Traffic Impact Study submitted by the school district.

But along with traffic to and from school, construction traffic concerned Seaside planning commissioners, especially the 25,000 truck trips expected up and down local streets.

The more trips, the more damage, and the heavier vehicles, the more the damage, Commissioner Bill Carpenter said. “A tractor-trailer weighing 80,000 pounds is expected to do 7,800 more times damage to a road than a passenger car.”

The district expects 18,000 concrete trucks and 10,000 loads of imported gravel, he said. With added loads of asphalt, rebar and structural steel, construction traffic could exceed 25,000 truck trips, the equivalent of 1.5 million automotive trips over an 18-month period, which could significantly reduce the life of roadways.

Carpenter suggested traffic be diverted to logging roads to mitigate some of these impacts, which would be greatest on Spruce Drive leading to the campus.

Traffic is dependent on the weather and the sequencing of the work, school district architect Dan Hess responded. “The contractor would rather not use Spruce if they could avoid it.” But in bad weather, logging roads may not be an option. “Contractors want to stay off Spruce, but they have to be practical about how they do their work as well,” Hess said.

Commissioners addressed concerns of backups along Avenue S near Highway 101, especially delays that could be caused by buildup of construction traffic.

“The number of cars that line up along Avenue S and 101 is incredible,” Commissioner David Posalski said. “Getting around that corner could be extremely problematic.”

At the commission’s March 6 session, traffic impacts and safety were elements of discussion. District consultants said they hope approval of their conditional use permit will be delivered at a third commission meeting on April 3, which would keep construction on track for a June 1 groundbreaking. The district hopes to open for students in September 2020.

Commissioners unanimously voted to keep the record open for the April 3 meeting, which would include written testimony and responses from the district.