Thanks again to all signers for supporting a more rational approach to constructing the SR 520 viaduct replacement over Portage Bay.

Members of the SR 520 working met with representatives of the Puget Sound Clean Air Agency (PSCAA) in late December of 2022 to discuss the impact of work bridge traffic on neighborhood air quality. Pollution from construction vehicles is of concern because the work bridge approach forces the vast majority of material transport to utilize a large number construction trucks carrying relatively small loads through neighborhood streets.

Vehicles manufactured after 2008 meeting the Environmental Protection Agency “Tier 4” air quality requirements produce dramatically lower pollutants than vehicles manufactured before 2008. In terms of dollar value of health impacts PSCAA agency staff calculate that use of vehicles meeting Tier 4 standards would reduce air quality related health impacts to one third the level produced by use of older vehicles.

The SR 520 Working group is asking the legislature and WSDOT to require that contractors use vehicles meeting Tier 4 requirements.

An even better solution for air quality is a barge approach which can utilize relatively few, much heavier and larger loads. Barges can also promote dramatic cost savings by allowing the use of long span precast girders which are difficult or impossible to transport by trucks.

The SR 520 working group is in the process of preparing a response to the WSDOT authored clarification many of you received from WSDOT staff. We hope to post this next week. We feel confident our response will strengthen arguments that building from barges is a faster, cheaper and lower impact approach.

Please keep on sharing, we have surpassed 650 signatures and are on our way to the lofty goal of 1,000 signatures. Elected officials are listening and the pressure is building on WSDOT to take a more rational approach to construction of the SR 520 viaduct replacement.