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RCW 46.37.420 Tire Restrictions: What Washington Drivers Need to Know

RCW 46.37.420 establishes tire regulations for vehicles operating on Washington State highways. These laws are designed to ensure road safety, protect infrastructure, and promote the responsible use of traction devices during winter weather.

Requirements for Tire Types on Public Roads

Under RCW 46.37.420, all vehicles must be equipped with pneumatic rubber tires. These are the standard air-filled tires used on passenger vehicles, commercial trucks, and motorcycles. The only exception is temporary-use spare tires that comply with federal standards and are installed per manufacturer instructions.

Prohibited Tire Features

To prevent damage to roadways and ensure public safety, Washington law prohibits the use of tires with:

  • Blocks
  • Flanges
  • Cleats
  • Spikes
  • Any other protrusions made of materials other than rubber that extend beyond the tire’s tread surface

However, exceptions exist. Farm machinery with pneumatic tires or solid rubber tracks can use these features if they won’t damage the highway.

During winter months, certain traction aids are permitted:

  • Tire chains and alternative traction devices are allowed when snow, ice, or skid conditions exist.
  • Studded tires are allowed only between November 1 and April 1.

A key update in the law allows retractable studded tires to be used year-round, provided:

  • The studs retract below the tire’s wear bar when not in use.
  • The studs are only engaged during the legal studded tire season.

Retractable studs can be made of metal or other materials and are exempt from the lightweight stud weight requirements.

The Washington State Department of Transportation (WSDOT) can modify the legal period for studded tire use based on weather or safety conditions.

Special Permits and Exceptions

The law permits WSDOT and local jurisdictions to issue special permits for certain vehicles such as:

  • Tractors with movable tracks
  • Farm machinery with specialized traction features

Additionally, school buses and fire department vehicles may use studded tires during the winter period without penalty.

Why RCW 46.37.420 Tire Restrictions Matter

These tire regulations are vital for:

  • Road safety: Reducing the risk of accidents during winter or in poor road conditions
  • Infrastructure preservation: Preventing damage caused by unauthorized tire equipment
  • Legal compliance: Avoiding citations and fines from improper tire use

For Washington drivers, understanding these laws is essential for safe and lawful travel.

Call to Action

Contact Blanford Law today at ken@blanfordlaw.com or 253-720-9304 for guidance on your legal matter.

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