The Arizona Department of Transportation is building a pedestrian underpass next to the Mariposa Port of Entry in Nogales with the expected cost of the project at more than $3 million.
ADOT officials say the 10-foot-by-10-foot concrete box culvert will extend 356 feet and include a ventilation system and lighting.
The agency also plans to build new sidewalks, add traffic signals and make storm drain improvements.
ADOT expects to finish the project in December.
Officials say the underpass will allow pedestrians to safely walk to and from the port of entry along Arizona 189.
As it stands, pedestrians and tractor-trailer traffic are not separated in the state's right-of-way.
Copyright 2015 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.