Truck lane designations & restrictions

Truck lane designations and restrictions help to reduce collisions or congestion by separating or restricting trucks into designated lanes.

Key characteristics





WSDOT regions

Strategy description

Truck lane designations and restrictions require trucks to stay within specified lanes. The purpose of truck lane designations to reduce congestion by separating trucks from regular traffic and to improve safety by separating slower moving trucks while climbing steep hills.

Although trucks are required to only use the truck-specific lanes, regular traffic is typically free to use those lanes as well. Signs may be used to discourage general traffic from using the designated lanes, but it is generally not enforceable.

Currently, there are only a few truck-only lanes in the United States. For example, California has implemented truck-only lanes on I-5 (1), and Georgia is considering adding truck-only lanes on I-75. Despite the potential benefits, a major disadvantage of designated truck-only lanes is the high cost of adding a new lane.

In addition to the potential to reduce collisions and congestion, other benefits of truck-only lanes include:

  • Improving capacity to keep trucks and their goods moving
  • Preserving the condition of general traffic lanes by reducing the damage that heavy trucks do to the roadway infrastructure

When to use this strategy

Truck lane designations and restrictions work best in areas where collisions or congestion are caused by high truck volumes.

For truck-only lanes, these make sense for congested highways that have:

  • Truck volumes that exceed 30 percent of the vehicles on the highway
  • Peak hour volumes that exceed 1,800 vehicles in each lane for an hour
  • Off-peak volumes that exceed 1,200 vehicles in each lane for an hour

Adapted from Caltrans Truck Only Lanes (1). 

Strategy benefits:

  • Reduce collisions by separating trucks from the general traffic
  • Reduce traffic congestion on general traffic lanes
  • Lower maintenance cost for other lanes since trucks do more damage to the roadway over time than general traffic
  • Truck-only lanes may enable trucks to follow closer using platooning technology, which could reduce drag and lead to a fuel savings

What you need in order to implement

Planning needs:

  • Analyze crash history and congestion and evaluate if designated truck lanes could reduce collisions or congestion
  • If considering truck-only lanes, conduct a feasibility study to identify locations where truck-only lanes may be suitable and achieve the desired benefits. Truck-only lanes are not common, so consider other TSMO strategies such as restricted lanes, climbing lanes, signage first.

Equipment needs:

  • Signs that identify the designated truck-only lane
  • Signs that identify whether general traffic can use the truck-only lane
  • May require adding a truck only lane

Learn more about this strategy

Works cited:

(1) Caltrans Truck Only Lanes

About key characteristics

Location notes:

Truck lane designations and restrictions can be useful on roadways in locations where collisions or congestion can be reduced by separating trucks into designated lanes. Specifically, locations with steep hills where slower truck traffic would benefit from having their own lane.

Cost notes:

Cost is low to implement truck restrictions. The cost becomes high if the agency needs to build an additional lane designated for trucks.

Technology notes:

Technology requirements are low because the restrictions and designated lanes are typically identified with signs and markings.

Collaboration notes:

Little collaboration is needed because truck lane designations and restrictions are typically implemented within one agency’s jurisdiction. Collaboration is often needed between the truck industry and transportation department, but is often limited to sharing information and receiving feedback.

Need or issue this strategy addresses