Why have permits?

When a bridge is constructed, the components are designed to carry the traffic that is supported by the road system leading to the bridge. With few exceptions, items such as the number and width of lanes, overhead clearances and load capacity must be able to support the types of vehicles that transit the street system routinely. These vehicles come in a wide variety of shapes and sizes and include all modes of transit from pedestrians, bicycles and horses to multi truck-trailer combinations and streetcar/light rail vehicles. Many of the major bridges in Portland were constructed at the beginning of the 20th Century, when cars and trucks were few and light in weight. A large percentage of traffic was horse-drawn. Street cars were the heaviest vehicles of their day and the early bridges (Hawthorne, Burnside and Broadway) all had rails to carry them across the Willamette River. These bridges were designed to carry vehicles that have a total gross weight (vehicle weight plus cargo weight) of 80,000 lbs.

Today's trucks are larger and may often exceed 100,000 lbs in total weight. They are taller, wider and more numerous than before. Cars are larger as well, necessitating the need to widen lanes. While many streets have been enlarged to handle these changes, bridges are more difficult to modify. Age and deterioration also contribute to lessening a bridge's ability to carry the loads it was designed for. For these reasons many bridges have restrictions on the size of vehicles that can safely cross them without causing damage to the bridge structure. Engineers inspect the bridges regularly and determine the load capacity of each structure. Recommendations are made and signs posted as needed to inform the public when a structure does not conform. In some cases, permits are granted to allow unusual loads to cross, but only after careful examination of the vehicle and cargo to be transported.

When is a permit required?

The table below contains many of the normal parameters for the bridges under Multnomah County's jurisdiction. Permits are required if the height, weight or width of a vehicle or cargo exceeds the dimensions shown.

Bridge Type 3 Vehicle

Type 3S2 Vehicle

Type 3-3 Vehicle
Sellwood River Spans 13 tons 13 tons 13 tons
Hawthorne River Spans 25 tons 40 tons 40 tons
Morrison River Spans 25 tons 40 tons 40 tons
Burnside River Spans 16 tons* 25 tons* 34 tons*
Broadway River Spans 25 tons 40 tons 40 tons

How do I know what is normal?

The table below shows some of the normal truck configurations and weights allowed to cross County bridges without permits. Additional information on truck configurations and weights may be found on the Oregon Department of Transportation's website.


Maximum weight without permit

H 20 Truck

H 20   

20 tons

Type 3 Truck

Type 3  

25 tons


Type 3S2   

40 tons

Truck Type 3-3;

Type 3-3   

40 tons

Other situations requiring permits

Special events that will impact normal traffic flow on the bridges also require permits. These events may include marches, parades, marathons, bicycle events, firework displays, movie and commercial filming and other events requiring the closure of one or more lanes to traffic.

How do I get a permit?

Permits for use of Multnomah County roads and bridges are administered by the Right-of-Way Section of the Transportation Division.