The Arizona Department of Transportation (ADOT) has announced that heavy trucks will be restricted to the right lane only on a 20 mile stretch of I-10 in hopes of improving safety.

In a June 7 announcement, ADOT said that the agency has installed signage along a stretch of I-10 between Phoenix and Casa Grande restricting truck traffic to the right lane only.

ADOT called the lane restriction an “interim safety measure” that will remain in place “until an improvement project kicks off to widen this segment of I-10.” The first stage of the construction project is expected to begin in 2023. ADOT says that the project could be completed “as early as 2026.”

The 20 mile lane restriction takes place on the final two-lane stretch of I-10 between Phoenix and Tucson that has yet to be widened to three lanes in each direction.

“This segment has safety concerns due to heavy traffic flow and truck traffic. The right-lane restriction for heavy vehicle truck traffic is intended to help reduce crashes, along with the resulting delays and closures due to these incidents. Based on data for the area where the signs are being posted, heavy vehicles were involved in about 20 percent of crashes and 15 percent of rear-end and sideswipe crashes,” ADOT said in a news release.

“The signs restricting heavy vehicle truck traffic to the right lane only are similar to those that ADOT has employed elsewhere, including I-17 north of Black Canyon City. Sign installation began Monday and is expected to continue through this week,” ADOT noted.

ADOT says that they will “closely monitor” traffic now that the signage is in place and the lane restrictions are in effect.