An investigative arm of Congress says in a report examining Detroit's entry port that traffic bottlenecks, a shortage of lanes and inspection points are long-term problems needing to be addressed.

The General Accounting Office outlined potential solutions for easing commercial and passenger traffic at the Ambassador Bridge and Detroit-Windsor Tunnel, even as security remains heightened due to the terrorism threat.

The main choke point in traffic flow was identified as the bridge cargo inspection plaza on the U.S. side. Bridge officials say they are waiting for the General Services Administration to sign off on the project.

Other proposals include providing Detroit with a permanent X-ray machine to scan trucks, supplementing a mobile X-ray machine. The GAO also recommended installing automated license plate reading devices, currently available at the U.S.-Mexico border.