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Load Rating for FAST Act Emergency Vehicles

Older bridges were not designed to carry the number and weight of today's vehicles. Today's bigger and heavier vehicles distribute weight differently, concentrating their weight on bridges in ways the structures were not designed to handle.

The 2015 federal FAST Act legalized select oversized emergency vehicles for use on the interstate highway system. As a result, ODOT must analyze bridges located within one mile of the interstate system and determine whether those structures can safely carry these specific vehicles.

How do we address this mandate?

By evaluating a bridge's safe carrying capacity with engineering analysis, or load rating. A load rating reflects the current condition of a bridge and serves as the foundation for posting load restrictions for overweight vehicles.

What did we do about it?

  1. We identified every structure within one mile of an interstate highway. (Approximately 1,175 bridges.)
  2. We conducted a load rating analysis on those structures.
  3. We determined which structures required a new or revised load rating. (Approximately 84.)
  4. We shared information about these federal mandates and of the work ahead with local road authorities and fire districts.
  5. We notified bridge owners (local road authorities) of new or revised load restrictions. Bridge owners are responsible for posting new signs, in compliance with standard federal regulations.

Are these bridges safe?

Yes, they are! A restriction does not mean a bridge is unsafe. It simply means the loads are limited.

Did we comply with this mandate?

Yes, we did! ODOT completed the work required by the Federal Highway Administration in response to the FAST Act.

EV2 and EV3 Emergency Vehicles Carry Weight Differently

Dipiction of vehicle configurations and their impact on a bridge 

While the EV2 and EV3 vehicles are similar weight to other standard trucks, they carry the weight differently.

Learn More About This Effort

ODOT is responsible for evaluating all public structures in the state to ensure they are able to carry standard, legal vehicles. 

If a bridge cannot safely carry legal vehicles, we limit the weight load to an amount the structure​ can carry safely - a weight restriction.

We work with local agency bridge owners to determine if there are ways to minimize impacts before the bridge is load rated and posted.​​​

Vehicle owners must comply with posted limits. Crossing a restricted bridge with an overweight vehicle is illegal.

The long-term integrity of the structure and safety of all travelers depends on compliance with these postings.​​

Currently, the legal maximum gross vehicle weight in Oregon is 80,000 lbs.​, with restrictions of no more than 20,000 lbs. on any single axle and 34,000 lbs. on any tandem axle.

Most emergency vehicles are well within these legal limits.

The FAST Act legalized two specific emergency vehicle configurations for the interstate system that go beyond these limits.​

The FAST Act legalized these vehicles to operate at a gross vehicle weight limit of 86,000 pounds, with the following additional limits, depending upon vehicle configuration:

  • 24,000 pounds on a single steering axle.
  • 33,500 pounds on a single drive axle.
  • 62,000 pounds on a tandem axle.
  • 52,000 pounds on a tandem rear drive steer axle.

Specifically, the act refers to two particular vehicle configurations known as EV2 and EV3 vehicles. These vehicles create higher load effects compared to the AASHTO legal loads that represent most emergency vehicles. The act nearly doubles the concentrated load on the tandem axle.

Specifics for the EV2 configuration include:

  • Front Single Axle: 24,000 pounds.
  • Rear Single Axle: 33,500 pounds.
  • Wheelbase: 15 ft.

For the EV3 configuration:

  • Front Single Axle: 24,000 pounds.
  • Rear Tandem Axle: 62,000 pounds (two 31,000 pound axles spaced at 4 ft.).
  • Wheelbase: 17 ft. (distance from front axle to the centerline of rear tandem axle).

No, bridge owners only need to post the bridges, as necessary.

Decisions on bridge upgrades are up to bridge owners to decide, based on their jurisdiction's needs.​

​There may be local funding options available to bridge owners. That will be a case-by-case basis.

As for state funds, city and county representatives voted unanimously at the May 2021 Local Agency Bridge Selection Committee meeting to follow established bridge funding cycles. 

Bridge condition and load rating factor into the sufficiency rating and project selection process.​

The 2015 FAST Act included new standards for emergency vehicles weight limits, legalizing two configurations to travel on the interstate system.

​The following year, the Federal Highway Administration directed states to load rate all bridges within one mile of the interstate system to ensure safe system access for these vehicles.

As a result, ODOT analyzed​ bridges statewide for the two emergency vehicles identified in the FAST Act. These are commonly referred to as EV2 and EV3.

Contact our Team

Joel Boothe, PE - ODOT Bridge Operations Manager

Jason Lawrence - Commerce and Compliance Policy Analyst